diff --git a/Cargo.lock b/Cargo.lock
index 176f9b441..a11eced7e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -4136,6 +4136,8 @@ checksum = "e421abadd41a4225275504ea4d6566923418b7f05506fbc9c0fe86ba7396114b"
 name = "turso"
 version = "0.1.3"
 dependencies = [
+ "rand 0.8.5",
+ "rand_chacha 0.3.1",
  "tempfile",
  "thiserror 2.0.12",
  "tokio",
diff --git a/bindings/javascript/src/lib.rs b/bindings/javascript/src/lib.rs
index 45ce3b958..e15cdaf7f 100644
--- a/bindings/javascript/src/lib.rs
+++ b/bindings/javascript/src/lib.rs
@@ -726,6 +726,14 @@ impl turso_core::DatabaseStorage for DatabaseFile {
     fn size(&self) -> turso_core::Result<u64> {
         self.file.size()
     }
+    fn truncate(
+        &self,
+        len: usize,
+        c: turso_core::Completion,
+    ) -> turso_core::Result<turso_core::Completion> {
+        let c = self.file.truncate(len, c)?;
+        Ok(c)
+    }
 }
 
 #[inline]
diff --git a/bindings/rust/Cargo.toml b/bindings/rust/Cargo.toml
index 557ad6e20..a1cdf873b 100644
--- a/bindings/rust/Cargo.toml
+++ b/bindings/rust/Cargo.toml
@@ -21,3 +21,5 @@ thiserror = "2.0.9"
 [dev-dependencies]
 tempfile = "3.20.0"
 tokio = { version = "1.29.1", features = ["full"] }
+rand = "0.8.5"
+rand_chacha = "0.3.1"
diff --git a/bindings/rust/tests/transaction_isolation_fuzz.rs b/bindings/rust/tests/transaction_isolation_fuzz.rs
new file mode 100644
index 000000000..84190d7d4
--- /dev/null
+++ b/bindings/rust/tests/transaction_isolation_fuzz.rs
@@ -0,0 +1,569 @@
+use rand::seq::SliceRandom;
+use rand::Rng;
+use rand_chacha::{rand_core::SeedableRng, ChaCha8Rng};
+use std::collections::HashMap;
+use turso::{Builder, Value};
+
+// In-memory representation of the database state
+#[derive(Debug, Clone, PartialEq, Eq)]
+struct DbRow {
+    id: i64,
+    text: String,
+}
+
+impl std::fmt::Display for DbRow {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "(id={}, text={})", self.id, self.text)
+    }
+}
+
+#[derive(Debug, Clone)]
+struct TransactionState {
+    // What this transaction can see (snapshot)
+    visible_rows: HashMap<i64, DbRow>,
+    // Pending changes in this transaction
+    pending_changes: Vec<Operation>,
+}
+
+#[derive(Debug)]
+struct ShadowDb {
+    // Committed state (what's actually in the database)
+    committed_rows: HashMap<i64, DbRow>,
+    // Transaction states
+    transactions: HashMap<usize, Option<TransactionState>>,
+}
+
+impl ShadowDb {
+    fn new() -> Self {
+        Self {
+            committed_rows: HashMap::new(),
+            transactions: HashMap::new(),
+        }
+    }
+
+    fn begin_transaction(&mut self, tx_id: usize, immediate: bool) {
+        self.transactions.insert(
+            tx_id,
+            if immediate {
+                Some(TransactionState {
+                    visible_rows: self.committed_rows.clone(),
+                    pending_changes: Vec::new(),
+                })
+            } else {
+                None
+            },
+        );
+    }
+
+    fn take_snapshot(&mut self, tx_id: usize) {
+        if let Some(tx_state) = self.transactions.get_mut(&tx_id) {
+            assert!(tx_state.is_none());
+            tx_state.replace(TransactionState {
+                visible_rows: self.committed_rows.clone(),
+                pending_changes: Vec::new(),
+            });
+        }
+    }
+
+    fn commit_transaction(&mut self, tx_id: usize) {
+        if let Some(tx_state) = self.transactions.remove(&tx_id) {
+            let tx_state = tx_state.unwrap();
+            // Apply pending changes to committed state
+            for op in tx_state.pending_changes {
+                match op {
+                    Operation::Insert { id, text } => {
+                        self.committed_rows.insert(id, DbRow { id, text });
+                    }
+                    Operation::Update { id, text } => {
+                        self.committed_rows.insert(id, DbRow { id, text });
+                    }
+                    Operation::Delete { id } => {
+                        self.committed_rows.remove(&id);
+                    }
+                    other => unreachable!("Unexpected operation: {other}"),
+                }
+            }
+        }
+    }
+
+    fn rollback_transaction(&mut self, tx_id: usize) {
+        self.transactions.remove(&tx_id);
+    }
+
+    fn insert(&mut self, tx_id: usize, id: i64, text: String) -> Result<(), String> {
+        if let Some(tx_state) = self.transactions.get_mut(&tx_id) {
+            // Check if row exists in visible state
+            if tx_state.as_ref().unwrap().visible_rows.contains_key(&id) {
+                return Err("UNIQUE constraint failed".to_string());
+            }
+            let row = DbRow {
+                id,
+                text: text.clone(),
+            };
+            tx_state
+                .as_mut()
+                .unwrap()
+                .pending_changes
+                .push(Operation::Insert { id, text });
+            tx_state.as_mut().unwrap().visible_rows.insert(id, row);
+            Ok(())
+        } else {
+            Err("No active transaction".to_string())
+        }
+    }
+
+    fn update(&mut self, tx_id: usize, id: i64, text: String) -> Result<(), String> {
+        if let Some(tx_state) = self.transactions.get_mut(&tx_id) {
+            // Check if row exists in visible state
+            if !tx_state.as_ref().unwrap().visible_rows.contains_key(&id) {
+                return Err("Row not found".to_string());
+            }
+            let row = DbRow {
+                id,
+                text: text.clone(),
+            };
+            tx_state
+                .as_mut()
+                .unwrap()
+                .pending_changes
+                .push(Operation::Update { id, text });
+            tx_state.as_mut().unwrap().visible_rows.insert(id, row);
+            Ok(())
+        } else {
+            Err("No active transaction".to_string())
+        }
+    }
+
+    fn delete(&mut self, tx_id: usize, id: i64) -> Result<(), String> {
+        if let Some(tx_state) = self.transactions.get_mut(&tx_id) {
+            // Check if row exists in visible state
+            if !tx_state.as_ref().unwrap().visible_rows.contains_key(&id) {
+                return Err("Row not found".to_string());
+            }
+            tx_state
+                .as_mut()
+                .unwrap()
+                .pending_changes
+                .push(Operation::Delete { id });
+            tx_state.as_mut().unwrap().visible_rows.remove(&id);
+            Ok(())
+        } else {
+            Err("No active transaction".to_string())
+        }
+    }
+
+    fn get_visible_rows(&self, tx_id: Option<usize>) -> Vec<DbRow> {
+        let Some(tx_id) = tx_id else {
+            // No transaction - see committed state
+            return self.committed_rows.values().cloned().collect();
+        };
+        if let Some(tx_state) = self.transactions.get(&tx_id) {
+            let tx_state = tx_state.as_ref().unwrap();
+            tx_state.visible_rows.values().cloned().collect()
+        } else {
+            // No transaction - see committed state
+            self.committed_rows.values().cloned().collect()
+        }
+    }
+}
+
+#[derive(Debug, Clone)]
+enum Operation {
+    Begin,
+    Commit,
+    Rollback,
+    Insert { id: i64, text: String },
+    Update { id: i64, text: String },
+    Delete { id: i64 },
+    Select,
+}
+
+impl std::fmt::Display for Operation {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            Operation::Begin => write!(f, "BEGIN"),
+            Operation::Commit => write!(f, "COMMIT"),
+            Operation::Rollback => write!(f, "ROLLBACK"),
+            Operation::Insert { id, text } => {
+                write!(f, "INSERT INTO test_table (id, text) VALUES ({id}, {text})")
+            }
+            Operation::Update { id, text } => {
+                write!(f, "UPDATE test_table SET text = {text} WHERE id = {id}")
+            }
+            Operation::Delete { id } => write!(f, "DELETE FROM test_table WHERE id = {id}"),
+            Operation::Select => write!(f, "SELECT * FROM test_table"),
+        }
+    }
+}
+
+fn rng_from_time_or_env() -> (ChaCha8Rng, u64) {
+    let seed = std::env::var("SEED").map_or(
+        std::time::SystemTime::now()
+            .duration_since(std::time::UNIX_EPOCH)
+            .unwrap()
+            .as_millis(),
+        |v| {
+            v.parse()
+                .expect("Failed to parse SEED environment variable as u64")
+        },
+    );
+    let rng = ChaCha8Rng::seed_from_u64(seed as u64);
+    (rng, seed as u64)
+}
+
+#[tokio::test]
+/// Verify translation isolation semantics with multiple concurrent connections.
+/// This test is ignored because it still fails sometimes; unsure if it fails due to a bug in the test or a bug in the implementation.
+async fn test_multiple_connections_fuzz() {
+    let (mut rng, seed) = rng_from_time_or_env();
+    println!("Multiple connections fuzz test seed: {seed}");
+
+    const NUM_ITERATIONS: usize = 50;
+    const OPERATIONS_PER_CONNECTION: usize = 30;
+    const NUM_CONNECTIONS: usize = 2;
+
+    for iteration in 0..NUM_ITERATIONS {
+        // Create a fresh database for each iteration
+        let tempfile = tempfile::NamedTempFile::new().unwrap();
+        let db = Builder::new_local(tempfile.path().to_str().unwrap())
+            .build()
+            .await
+            .unwrap();
+
+        // SHARED shadow database for all connections
+        let mut shared_shadow_db = ShadowDb::new();
+        let mut next_tx_id = 0;
+
+        // Create connections
+        let mut connections = Vec::new();
+        for conn_id in 0..NUM_CONNECTIONS {
+            let conn = db.connect().unwrap();
+
+            // Create table if it doesn't exist
+            conn.execute(
+                "CREATE TABLE IF NOT EXISTS test_table (id INTEGER PRIMARY KEY, text TEXT)",
+                (),
+            )
+            .await
+            .unwrap();
+
+            connections.push((conn, conn_id, None::<usize>)); // (connection, conn_id, current_tx_id)
+        }
+
+        // Interleave operations between all connections
+        for op_num in 0..OPERATIONS_PER_CONNECTION {
+            for (conn, conn_id, current_tx_id) in &mut connections {
+                // Generate operation based on current transaction state
+                let visible_rows = if let Some(tx_id) = *current_tx_id {
+                    // Take snapshot during first operation after a BEGIN, not immediately at BEGIN (the semantics is BEGIN DEFERRED)
+                    let tx_state = shared_shadow_db.transactions.get(&tx_id).unwrap();
+                    if tx_state.is_none() {
+                        shared_shadow_db.take_snapshot(tx_id);
+                    }
+                    shared_shadow_db.get_visible_rows(Some(tx_id))
+                } else {
+                    shared_shadow_db.get_visible_rows(None) // No transaction
+                };
+
+                let operation =
+                    generate_operation(&mut rng, current_tx_id.is_some(), &visible_rows);
+
+                println!("Connection {conn_id}(op={op_num}): {operation}");
+
+                match operation {
+                    Operation::Begin => {
+                        shared_shadow_db.begin_transaction(next_tx_id, false);
+                        *current_tx_id = Some(next_tx_id);
+                        next_tx_id += 1;
+
+                        conn.execute("BEGIN", ()).await.unwrap();
+                    }
+                    Operation::Commit => {
+                        let Some(tx_id) = *current_tx_id else {
+                            panic!("Connection {conn_id}(op={op_num}) FAILED: No transaction");
+                        };
+                        // Try real DB commit first
+                        let result = conn.execute("COMMIT", ()).await;
+
+                        match result {
+                            Ok(_) => {
+                                // Success - update shadow DB
+                                shared_shadow_db.commit_transaction(tx_id);
+                                *current_tx_id = None;
+                            }
+                            Err(e) => {
+                                println!("Connection {conn_id}(op={op_num}) FAILED: {e}");
+                                if let Some(tx_id) = *current_tx_id {
+                                    shared_shadow_db.rollback_transaction(tx_id);
+                                    *current_tx_id = None;
+                                }
+
+                                // Check if it's an acceptable error
+                                if !e.to_string().contains("database is locked") {
+                                    panic!("Unexpected error during commit: {e}");
+                                }
+                            }
+                        }
+                    }
+                    Operation::Rollback => {
+                        if let Some(tx_id) = *current_tx_id {
+                            // Try real DB rollback first
+                            let result = conn.execute("ROLLBACK", ()).await;
+
+                            match result {
+                                Ok(_) => {
+                                    // Success - update shadow DB
+                                    shared_shadow_db.rollback_transaction(tx_id);
+                                    *current_tx_id = None;
+                                }
+                                Err(e) => {
+                                    println!("Connection {conn_id}(op={op_num}) FAILED: {e}");
+                                    shared_shadow_db.rollback_transaction(tx_id);
+                                    *current_tx_id = None;
+
+                                    // Check if it's an acceptable error
+                                    if !e.to_string().contains("Busy")
+                                        && !e.to_string().contains("database is locked")
+                                    {
+                                        panic!("Unexpected error during rollback: {e}");
+                                    }
+                                }
+                            }
+                        }
+                    }
+                    Operation::Insert { id, text } => {
+                        let result = conn
+                            .execute(
+                                "INSERT INTO test_table (id, text) VALUES (?, ?)",
+                                vec![Value::Integer(id), Value::Text(text.clone())],
+                            )
+                            .await;
+
+                        // Check if real DB operation succeeded
+                        match result {
+                            Ok(_) => {
+                                // Success - update shadow DB
+                                if let Some(tx_id) = *current_tx_id {
+                                    // In transaction - update transaction's view
+                                    shared_shadow_db.insert(tx_id, id, text.clone()).unwrap();
+                                } else {
+                                    // Auto-commit - update shadow DB committed state
+                                    shared_shadow_db.begin_transaction(next_tx_id, true);
+                                    shared_shadow_db
+                                        .insert(next_tx_id, id, text.clone())
+                                        .unwrap();
+                                    shared_shadow_db.commit_transaction(next_tx_id);
+                                    next_tx_id += 1;
+                                }
+                            }
+                            Err(e) => {
+                                println!("Connection {conn_id}(op={op_num}) FAILED: {e}");
+                                if let Some(tx_id) = *current_tx_id {
+                                    shared_shadow_db.rollback_transaction(tx_id);
+                                    *current_tx_id = None;
+                                }
+                                // Check if it's an acceptable error
+                                if !e.to_string().contains("database is locked") {
+                                    panic!("Unexpected error during insert: {e}");
+                                }
+                            }
+                        }
+                    }
+                    Operation::Update { id, text } => {
+                        let result = conn
+                            .execute(
+                                "UPDATE test_table SET text = ? WHERE id = ?",
+                                vec![Value::Text(text.clone()), Value::Integer(id)],
+                            )
+                            .await;
+
+                        // Check if real DB operation succeeded
+                        match result {
+                            Ok(_) => {
+                                // Success - update shadow DB
+                                if let Some(tx_id) = *current_tx_id {
+                                    // In transaction - update transaction's view
+                                    shared_shadow_db.update(tx_id, id, text.clone()).unwrap();
+                                } else {
+                                    // Auto-commit - update shadow DB committed state
+                                    shared_shadow_db.begin_transaction(next_tx_id, true);
+                                    shared_shadow_db
+                                        .update(next_tx_id, id, text.clone())
+                                        .unwrap();
+                                    shared_shadow_db.commit_transaction(next_tx_id);
+                                    next_tx_id += 1;
+                                }
+                            }
+                            Err(e) => {
+                                println!("Connection {conn_id}(op={op_num}) FAILED: {e}");
+                                if let Some(tx_id) = *current_tx_id {
+                                    shared_shadow_db.rollback_transaction(tx_id);
+                                    *current_tx_id = None;
+                                }
+                                // Check if it's an acceptable error
+                                if !e.to_string().contains("database is locked") {
+                                    panic!("Unexpected error during update: {e}");
+                                }
+                            }
+                        }
+                    }
+                    Operation::Delete { id } => {
+                        let result = conn
+                            .execute(
+                                "DELETE FROM test_table WHERE id = ?",
+                                vec![Value::Integer(id)],
+                            )
+                            .await;
+
+                        // Check if real DB operation succeeded
+                        match result {
+                            Ok(_) => {
+                                // Success - update shadow DB
+                                if let Some(tx_id) = *current_tx_id {
+                                    // In transaction - update transaction's view
+                                    shared_shadow_db.delete(tx_id, id).unwrap();
+                                } else {
+                                    // Auto-commit - update shadow DB committed state
+                                    shared_shadow_db.begin_transaction(next_tx_id, true);
+                                    shared_shadow_db.delete(next_tx_id, id).unwrap();
+                                    shared_shadow_db.commit_transaction(next_tx_id);
+                                    next_tx_id += 1;
+                                }
+                            }
+                            Err(e) => {
+                                println!("Connection {conn_id}(op={op_num}) FAILED: {e}");
+                                if let Some(tx_id) = *current_tx_id {
+                                    shared_shadow_db.rollback_transaction(tx_id);
+                                    *current_tx_id = None;
+                                }
+                                // Check if it's an acceptable error
+                                if !e.to_string().contains("database is locked") {
+                                    panic!("Unexpected error during delete: {e}");
+                                }
+                            }
+                        }
+                    }
+                    Operation::Select => {
+                        let query_str = "SELECT id, text FROM test_table ORDER BY id";
+                        let mut rows = conn.query(query_str, ()).await.unwrap();
+
+                        let mut real_rows = Vec::new();
+                        while let Some(row) = rows.next().await.unwrap() {
+                            let id = row.get_value(0).unwrap();
+                            let text = row.get_value(1).unwrap();
+
+                            if let (Value::Integer(id), Value::Text(text)) = (id, text) {
+                                real_rows.push(DbRow { id, text });
+                            }
+                        }
+                        real_rows.sort_by_key(|r| r.id);
+
+                        let mut expected_rows = visible_rows.clone();
+                        expected_rows.sort_by_key(|r| r.id);
+
+                        if real_rows != expected_rows {
+                            let diff = {
+                                let mut diff = Vec::new();
+                                for row in expected_rows.iter() {
+                                    if !real_rows.contains(row) {
+                                        diff.push(row);
+                                    }
+                                }
+                                for row in real_rows.iter() {
+                                    if !expected_rows.contains(row) {
+                                        diff.push(row);
+                                    }
+                                }
+                                diff
+                            };
+                            panic!(
+                                "Row mismatch in iteration {iteration} Connection {conn_id}(op={op_num}). Query: {query_str}.\n\nExpected: {}\n\nGot: {}\n\nDiff: {}\n\nSeed: {seed}",
+                                expected_rows.iter().map(|r| r.to_string()).collect::<Vec<_>>().join(", "),
+                                real_rows.iter().map(|r| r.to_string()).collect::<Vec<_>>().join(", "),
+                                diff.iter().map(|r| r.to_string()).collect::<Vec<_>>().join(", "),
+                            );
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+
+fn generate_operation(
+    rng: &mut ChaCha8Rng,
+    in_transaction: bool,
+    visible_rows: &[DbRow],
+) -> Operation {
+    match rng.gen_range(0..100) {
+        // 10% chance to begin transaction
+        0..=9 => {
+            if !in_transaction {
+                Operation::Begin
+            } else {
+                generate_data_operation(rng, visible_rows)
+            }
+        }
+        // 5% chance to commit
+        10..=14 => {
+            if in_transaction {
+                Operation::Commit
+            } else {
+                generate_data_operation(rng, visible_rows)
+            }
+        }
+        // 5% chance to rollback
+        15..=19 => {
+            if in_transaction {
+                Operation::Rollback
+            } else {
+                generate_data_operation(rng, visible_rows)
+            }
+        }
+        // 80% chance for data operations
+        _ => generate_data_operation(rng, visible_rows),
+    }
+}
+
+fn generate_data_operation(rng: &mut ChaCha8Rng, visible_rows: &[DbRow]) -> Operation {
+    match rng.gen_range(0..4) {
+        0 => {
+            // Insert - generate a new ID that doesn't exist
+            let id = if visible_rows.is_empty() {
+                rng.gen_range(1..1000)
+            } else {
+                let max_id = visible_rows.iter().map(|r| r.id).max().unwrap();
+                rng.gen_range(max_id + 1..max_id + 100)
+            };
+            let text = format!("text_{}", rng.gen_range(1..1000));
+            Operation::Insert { id, text }
+        }
+        1 => {
+            // Update - only if there are visible rows
+            if visible_rows.is_empty() {
+                // No rows to update, try insert instead
+                let id = rng.gen_range(1..1000);
+                let text = format!("text_{}", rng.gen_range(1..1000));
+                Operation::Insert { id, text }
+            } else {
+                let id = visible_rows.choose(rng).unwrap().id;
+                let text = format!("updated_{}", rng.gen_range(1..1000));
+                Operation::Update { id, text }
+            }
+        }
+        2 => {
+            // Delete - only if there are visible rows
+            if visible_rows.is_empty() {
+                // No rows to delete, try insert instead
+                let id = rng.gen_range(1..1000);
+                let text = format!("text_{}", rng.gen_range(1..1000));
+                Operation::Insert { id, text }
+            } else {
+                let id = visible_rows.choose(rng).unwrap().id;
+                Operation::Delete { id }
+            }
+        }
+        3 => Operation::Select,
+        _ => unreachable!(),
+    }
+}
diff --git a/bindings/wasm/lib.rs b/bindings/wasm/lib.rs
new file mode 100644
index 000000000..1996d073f
--- /dev/null
+++ b/bindings/wasm/lib.rs
@@ -0,0 +1,461 @@
+#[cfg(all(feature = "web", feature = "nodejs"))]
+compile_error!("Features 'web' and 'nodejs' cannot be enabled at the same time");
+
+use js_sys::{Array, Object};
+use std::cell::RefCell;
+use std::sync::Arc;
+use turso_core::{Clock, Instant, OpenFlags, Result};
+use wasm_bindgen::prelude::*;
+
+#[allow(dead_code)]
+#[wasm_bindgen]
+pub struct Database {
+    db: Arc<turso_core::Database>,
+    conn: Arc<turso_core::Connection>,
+}
+
+#[allow(clippy::arc_with_non_send_sync)]
+#[wasm_bindgen]
+impl Database {
+    #[wasm_bindgen(constructor)]
+    pub fn new(path: &str) -> Database {
+        let io: Arc<dyn turso_core::IO> = Arc::new(PlatformIO { vfs: VFS::new() });
+        let file = io.open_file(path, OpenFlags::Create, false).unwrap();
+        let db_file = Arc::new(DatabaseFile::new(file));
+        let db = turso_core::Database::open(io, path, db_file, false, false).unwrap();
+        let conn = db.connect().unwrap();
+        Database { db, conn }
+    }
+
+    #[wasm_bindgen]
+    pub fn exec(&self, _sql: &str) {
+        self.conn.execute(_sql).unwrap();
+    }
+
+    #[wasm_bindgen]
+    pub fn prepare(&self, _sql: &str) -> Statement {
+        let stmt = self.conn.prepare(_sql).unwrap();
+        Statement::new(RefCell::new(stmt), false)
+    }
+}
+
+#[wasm_bindgen]
+pub struct RowIterator {
+    inner: RefCell<turso_core::Statement>,
+}
+
+#[wasm_bindgen]
+impl RowIterator {
+    fn new(inner: RefCell<turso_core::Statement>) -> Self {
+        Self { inner }
+    }
+
+    #[wasm_bindgen]
+    #[allow(clippy::should_implement_trait)]
+    pub fn next(&mut self) -> JsValue {
+        let mut stmt = self.inner.borrow_mut();
+        match stmt.step() {
+            Ok(turso_core::StepResult::Row) => {
+                let row = stmt.row().unwrap();
+                let row_array = Array::new();
+                for value in row.get_values() {
+                    let value = to_js_value(value);
+                    row_array.push(&value);
+                }
+                JsValue::from(row_array)
+            }
+            Ok(turso_core::StepResult::IO) => JsValue::UNDEFINED,
+            Ok(turso_core::StepResult::Done) | Ok(turso_core::StepResult::Interrupt) => {
+                JsValue::UNDEFINED
+            }
+
+            Ok(turso_core::StepResult::Busy) => JsValue::UNDEFINED,
+            Err(e) => panic!("Error: {e:?}"),
+        }
+    }
+}
+
+#[wasm_bindgen]
+pub struct Statement {
+    inner: RefCell<turso_core::Statement>,
+    raw: bool,
+}
+
+#[wasm_bindgen]
+impl Statement {
+    fn new(inner: RefCell<turso_core::Statement>, raw: bool) -> Self {
+        Self { inner, raw }
+    }
+
+    #[wasm_bindgen]
+    pub fn raw(mut self, toggle: Option<bool>) -> Self {
+        self.raw = toggle.unwrap_or(true);
+        self
+    }
+
+    pub fn get(&self) -> JsValue {
+        let mut stmt = self.inner.borrow_mut();
+        match stmt.step() {
+            Ok(turso_core::StepResult::Row) => {
+                let row = stmt.row().unwrap();
+                let row_array = js_sys::Array::new();
+                for value in row.get_values() {
+                    let value = to_js_value(value);
+                    row_array.push(&value);
+                }
+                JsValue::from(row_array)
+            }
+
+            Ok(turso_core::StepResult::IO)
+            | Ok(turso_core::StepResult::Done)
+            | Ok(turso_core::StepResult::Interrupt)
+            | Ok(turso_core::StepResult::Busy) => JsValue::UNDEFINED,
+            Err(e) => panic!("Error: {e:?}"),
+        }
+    }
+
+    pub fn all(&self) -> js_sys::Array {
+        let array = js_sys::Array::new();
+        loop {
+            let mut stmt = self.inner.borrow_mut();
+            match stmt.step() {
+                Ok(turso_core::StepResult::Row) => {
+                    let row = stmt.row().unwrap();
+                    let row_array = js_sys::Array::new();
+                    for value in row.get_values() {
+                        let value = to_js_value(value);
+                        row_array.push(&value);
+                    }
+                    array.push(&row_array);
+                }
+                Ok(turso_core::StepResult::IO) => {}
+                Ok(turso_core::StepResult::Interrupt) => break,
+                Ok(turso_core::StepResult::Done) => break,
+                Ok(turso_core::StepResult::Busy) => break,
+                Err(e) => panic!("Error: {e:?}"),
+            }
+        }
+        array
+    }
+
+    #[wasm_bindgen]
+    pub fn iterate(self) -> JsValue {
+        let iterator = RowIterator::new(self.inner);
+        let iterator_obj = Object::new();
+
+        // Define the next method that will be called by JavaScript
+        let next_fn = js_sys::Function::new_with_args(
+            "",
+            "const value = this.iterator.next();
+             const done = value === undefined;
+             return {
+                value,
+                done
+             };",
+        );
+
+        js_sys::Reflect::set(&iterator_obj, &JsValue::from_str("next"), &next_fn).unwrap();
+
+        js_sys::Reflect::set(
+            &iterator_obj,
+            &JsValue::from_str("iterator"),
+            &JsValue::from(iterator),
+        )
+        .unwrap();
+
+        let symbol_iterator = js_sys::Function::new_no_args("return this;");
+        js_sys::Reflect::set(&iterator_obj, &js_sys::Symbol::iterator(), &symbol_iterator).unwrap();
+
+        JsValue::from(iterator_obj)
+    }
+}
+
+fn to_js_value(value: &turso_core::Value) -> JsValue {
+    match value {
+        turso_core::Value::Null => JsValue::null(),
+        turso_core::Value::Integer(i) => {
+            let i = *i;
+            if i >= i32::MIN as i64 && i <= i32::MAX as i64 {
+                JsValue::from(i as i32)
+            } else {
+                JsValue::from(i)
+            }
+        }
+        turso_core::Value::Float(f) => JsValue::from(*f),
+        turso_core::Value::Text(t) => JsValue::from_str(t.as_str()),
+        turso_core::Value::Blob(b) => js_sys::Uint8Array::from(b.as_slice()).into(),
+    }
+}
+
+pub struct File {
+    vfs: VFS,
+    fd: i32,
+}
+
+unsafe impl Send for File {}
+unsafe impl Sync for File {}
+
+#[allow(dead_code)]
+impl File {
+    fn new(vfs: VFS, fd: i32) -> Self {
+        Self { vfs, fd }
+    }
+}
+
+impl turso_core::File for File {
+    fn lock_file(&self, _exclusive: bool) -> Result<()> {
+        // TODO
+        Ok(())
+    }
+
+    fn unlock_file(&self) -> Result<()> {
+        // TODO
+        Ok(())
+    }
+
+    fn pread(
+        &self,
+        pos: usize,
+        c: turso_core::Completion,
+    ) -> Result<turso_core::Completion> {
+        let r = match c.completion_type {
+            turso_core::CompletionType::Read(ref r) => r,
+            _ => unreachable!(),
+        };
+        let nr = {
+            let mut buf = r.buf_mut();
+            let buf: &mut [u8] = buf.as_mut_slice();
+            self.vfs.pread(self.fd, buf, pos)
+        };
+        r.complete(nr);
+        #[allow(clippy::arc_with_non_send_sync)]
+        Ok(c)
+    }
+
+    fn pwrite(
+        &self,
+        pos: usize,
+        buffer: Arc<std::cell::RefCell<turso_core::Buffer>>,
+        c: turso_core::Completion,
+    ) -> Result<turso_core::Completion> {
+        let w = match c.completion_type {
+            turso_core::CompletionType::Write(ref w) => w,
+            _ => unreachable!(),
+        };
+        let buf = buffer.borrow();
+        let buf: &[u8] = buf.as_slice();
+        self.vfs.pwrite(self.fd, buf, pos);
+        w.complete(buf.len() as i32);
+        #[allow(clippy::arc_with_non_send_sync)]
+        Ok(c)
+    }
+
+    fn sync(&self, c: turso_core::Completion) -> Result<turso_core::Completion> {
+        self.vfs.sync(self.fd);
+        c.complete(0);
+        #[allow(clippy::arc_with_non_send_sync)]
+        Ok(c)
+    }
+
+    fn size(&self) -> Result<u64> {
+        Ok(self.vfs.size(self.fd))
+    }
+
+    fn truncate(
+        &self,
+        len: usize,
+        c: turso_core::Completion,
+    ) -> Result<turso_core::Completion> {
+        self.vfs.truncate(self.fd, len);
+        c.complete(0);
+        #[allow(clippy::arc_with_non_send_sync)]
+        Ok(c)
+    }
+}
+
+pub struct PlatformIO {
+    vfs: VFS,
+}
+unsafe impl Send for PlatformIO {}
+unsafe impl Sync for PlatformIO {}
+
+impl Clock for PlatformIO {
+    fn now(&self) -> Instant {
+        let date = Date::new();
+        let ms_since_epoch = date.getTime();
+
+        Instant {
+            secs: (ms_since_epoch / 1000.0) as i64,
+            micros: ((ms_since_epoch % 1000.0) * 1000.0) as u32,
+        }
+    }
+}
+
+impl turso_core::IO for PlatformIO {
+    fn open_file(
+        &self,
+        path: &str,
+        _flags: OpenFlags,
+        _direct: bool,
+    ) -> Result<Arc<dyn turso_core::File>> {
+        let fd = self.vfs.open(path, "a+");
+        Ok(Arc::new(File {
+            vfs: VFS::new(),
+            fd,
+        }))
+    }
+
+    fn wait_for_completion(&self, c: turso_core::Completion) -> Result<()> {
+        while !c.is_completed() {
+            self.run_once()?;
+        }
+        Ok(())
+    }
+
+    fn run_once(&self) -> Result<()> {
+        Ok(())
+    }
+
+    fn generate_random_number(&self) -> i64 {
+        let mut buf = [0u8; 8];
+        getrandom::getrandom(&mut buf).unwrap();
+        i64::from_ne_bytes(buf)
+    }
+
+    fn get_memory_io(&self) -> Arc<turso_core::MemoryIO> {
+        Arc::new(turso_core::MemoryIO::new())
+    }
+}
+
+#[wasm_bindgen]
+extern "C" {
+    type Date;
+
+    #[wasm_bindgen(constructor)]
+    fn new() -> Date;
+
+    #[wasm_bindgen(method, getter)]
+    fn toISOString(this: &Date) -> String;
+
+    #[wasm_bindgen(method)]
+    fn getTime(this: &Date) -> f64;
+}
+
+pub struct DatabaseFile {
+    file: Arc<dyn turso_core::File>,
+}
+
+unsafe impl Send for DatabaseFile {}
+unsafe impl Sync for DatabaseFile {}
+
+impl DatabaseFile {
+    pub fn new(file: Arc<dyn turso_core::File>) -> Self {
+        Self { file }
+    }
+}
+
+impl turso_core::DatabaseStorage for DatabaseFile {
+    fn read_page(&self, page_idx: usize, c: turso_core::Completion) -> Result<()> {
+        let r = match c.completion_type {
+            turso_core::CompletionType::Read(ref r) => r,
+            _ => unreachable!(),
+        };
+        let size = r.buf().len();
+        assert!(page_idx > 0);
+        if !(512..=65536).contains(&size) || size & (size - 1) != 0 {
+            return Err(turso_core::LimboError::NotADB);
+        }
+        let pos = (page_idx - 1) * size;
+        self.file.pread(pos, c.into())?;
+        Ok(())
+    }
+
+    fn write_page(
+        &self,
+        page_idx: usize,
+        buffer: Arc<std::cell::RefCell<turso_core::Buffer>>,
+        c: turso_core::Completion,
+    ) -> Result<()> {
+        let size = buffer.borrow().len();
+        let pos = (page_idx - 1) * size;
+        self.file.pwrite(pos, buffer, c.into())?;
+        Ok(())
+    }
+
+    fn sync(&self, c: turso_core::Completion) -> Result<()> {
+        let _ = self.file.sync(c.into())?;
+        Ok(())
+    }
+
+    fn size(&self) -> Result<u64> {
+        self.file.size()
+    }
+
+    fn truncate(&self, len: usize, c: turso_core::Completion) -> Result<()> {
+        self.file.truncate(len, c)?;
+        Ok(())
+    }
+}
+
+#[cfg(all(feature = "web", not(feature = "nodejs")))]
+#[wasm_bindgen(module = "/web/src/web-vfs.js")]
+extern "C" {
+    type VFS;
+    #[wasm_bindgen(constructor)]
+    fn new() -> VFS;
+
+    #[wasm_bindgen(method)]
+    fn open(this: &VFS, path: &str, flags: &str) -> i32;
+
+    #[wasm_bindgen(method)]
+    fn close(this: &VFS, fd: i32) -> bool;
+
+    #[wasm_bindgen(method)]
+    fn pwrite(this: &VFS, fd: i32, buffer: &[u8], offset: usize) -> i32;
+
+    #[wasm_bindgen(method)]
+    fn pread(this: &VFS, fd: i32, buffer: &mut [u8], offset: usize) -> i32;
+
+    #[wasm_bindgen(method)]
+    fn size(this: &VFS, fd: i32) -> u64;
+
+    #[wasm_bindgen(method)]
+    fn truncate(this: &VFS, fd: i32, len: usize);
+
+    #[wasm_bindgen(method)]
+    fn sync(this: &VFS, fd: i32);
+}
+
+#[cfg(all(feature = "nodejs", not(feature = "web")))]
+#[wasm_bindgen(module = "/node/src/vfs.cjs")]
+extern "C" {
+    type VFS;
+    #[wasm_bindgen(constructor)]
+    fn new() -> VFS;
+
+    #[wasm_bindgen(method)]
+    fn open(this: &VFS, path: &str, flags: &str) -> i32;
+
+    #[wasm_bindgen(method)]
+    fn close(this: &VFS, fd: i32) -> bool;
+
+    #[wasm_bindgen(method)]
+    fn pwrite(this: &VFS, fd: i32, buffer: &[u8], offset: usize) -> i32;
+
+    #[wasm_bindgen(method)]
+    fn pread(this: &VFS, fd: i32, buffer: &mut [u8], offset: usize) -> i32;
+
+    #[wasm_bindgen(method)]
+    fn size(this: &VFS, fd: i32) -> u64;
+
+    #[wasm_bindgen(method)]
+    fn truncate(this: &VFS, fd: i32, len: usize);
+
+    #[wasm_bindgen(method)]
+    fn sync(this: &VFS, fd: i32);
+}
+
+#[wasm_bindgen(start)]
+pub fn init() {
+    console_error_panic_hook::set_once();
+}
diff --git a/cli/app.rs b/cli/app.rs
index fa98d04a8..2b422af86 100644
--- a/cli/app.rs
+++ b/cli/app.rs
@@ -613,8 +613,8 @@ impl Limbo {
                     std::process::exit(0)
                 }
                 Command::Open(args) => {
-                    if self.open_db(&args.path, args.vfs_name.as_deref()).is_err() {
-                        let _ = self.writeln("Error: Unable to open database file.");
+                    if let Err(e) = self.open_db(&args.path, args.vfs_name.as_deref()) {
+                        let _ = self.writeln(e.to_string());
                     }
                 }
                 Command::Schema(args) => {
diff --git a/core/io/generic.rs b/core/io/generic.rs
index 15ce52564..5bfda1db0 100644
--- a/core/io/generic.rs
+++ b/core/io/generic.rs
@@ -121,6 +121,14 @@ impl File for GenericFile {
         Ok(c)
     }
 
+    fn truncate(&self, len: usize, c: Completion) -> Result<Completion> {
+        let mut file = self.file.borrow_mut();
+        file.set_len(len as u64)
+            .map_err(|err| LimboError::IOError(err))?;
+        c.complete(0);
+        Ok(c)
+    }
+
     fn size(&self) -> Result<u64> {
         let file = self.file.borrow();
         Ok(file.metadata().unwrap().len())
diff --git a/core/io/io_uring.rs b/core/io/io_uring.rs
index 2ccb3e30a..f33c04db3 100644
--- a/core/io/io_uring.rs
+++ b/core/io/io_uring.rs
@@ -226,7 +226,7 @@ impl Clock for UringIO {
 /// use the callback pointer as the user_data for the operation as is
 /// common practice for io_uring to prevent more indirection
 fn get_key(c: Completion) -> u64 {
-    Arc::into_raw(c.inner) as u64
+    Arc::into_raw(c.inner.clone()) as u64
 }
 
 #[inline(always)]
@@ -353,6 +353,17 @@ impl File for UringFile {
     fn size(&self) -> Result<u64> {
         Ok(self.file.metadata()?.len())
     }
+
+    fn truncate(&self, len: usize, c: Completion) -> Result<Completion> {
+        let mut io = self.io.borrow_mut();
+        let truncate = with_fd!(self, |fd| {
+            io_uring::opcode::Ftruncate::new(fd, len as u64)
+                .build()
+                .user_data(get_key(c.clone()))
+        });
+        io.ring.submit_entry(&truncate);
+        Ok(c)
+    }
 }
 
 impl Drop for UringFile {
diff --git a/core/io/memory.rs b/core/io/memory.rs
index aed9531c1..7dbf05d50 100644
--- a/core/io/memory.rs
+++ b/core/io/memory.rs
@@ -174,6 +174,19 @@ impl File for MemoryFile {
         Ok(c)
     }
 
+    fn truncate(&self, len: usize, c: Completion) -> Result<Completion> {
+        if len < self.size.get() {
+            // Truncate pages
+            unsafe {
+                let pages = &mut *self.pages.get();
+                pages.retain(|&k, _| k * PAGE_SIZE < len);
+            }
+        }
+        self.size.set(len);
+        c.complete(0);
+        Ok(c)
+    }
+
     fn size(&self) -> Result<u64> {
         Ok(self.size.get() as u64)
     }
diff --git a/core/io/mod.rs b/core/io/mod.rs
index b58c17ab6..82ef51313 100644
--- a/core/io/mod.rs
+++ b/core/io/mod.rs
@@ -19,6 +19,7 @@ pub trait File: Send + Sync {
         -> Result<Completion>;
     fn sync(&self, c: Completion) -> Result<Completion>;
     fn size(&self) -> Result<u64>;
+    fn truncate(&self, len: usize, c: Completion) -> Result<Completion>;
 }
 
 #[derive(Debug, Copy, Clone, PartialEq)]
@@ -53,6 +54,7 @@ pub trait IO: Clock + Send + Sync {
 pub type Complete = dyn Fn(Arc<RefCell<Buffer>>, i32);
 pub type WriteComplete = dyn Fn(i32);
 pub type SyncComplete = dyn Fn(i32);
+pub type TruncateComplete = dyn Fn(i32);
 
 #[must_use]
 #[derive(Clone)]
@@ -69,6 +71,7 @@ pub enum CompletionType {
     Read(ReadCompletion),
     Write(WriteCompletion),
     Sync(SyncCompletion),
+    Truncate(TruncateCompletion),
 }
 
 pub struct ReadCompletion {
@@ -113,6 +116,14 @@ impl Completion {
         ))))
     }
 
+    pub fn new_trunc<F>(complete: F) -> Self
+    where
+        F: Fn(i32) + 'static,
+    {
+        Self::new(CompletionType::Truncate(TruncateCompletion::new(Box::new(
+            complete,
+        ))))
+    }
     pub fn is_completed(&self) -> bool {
         self.inner.is_completed.get()
     }
@@ -122,6 +133,7 @@ impl Completion {
             CompletionType::Read(r) => r.complete(result),
             CompletionType::Write(w) => w.complete(result),
             CompletionType::Sync(s) => s.complete(result), // fix
+            CompletionType::Truncate(t) => t.complete(result),
         };
         self.inner.is_completed.set(true);
     }
@@ -191,6 +203,20 @@ impl SyncCompletion {
     }
 }
 
+pub struct TruncateCompletion {
+    pub complete: Box<TruncateComplete>,
+}
+
+impl TruncateCompletion {
+    pub fn new(complete: Box<TruncateComplete>) -> Self {
+        Self { complete }
+    }
+
+    pub fn complete(&self, res: i32) {
+        (self.complete)(res);
+    }
+}
+
 pub type BufferData = Pin<Vec<u8>>;
 
 pub type BufferDropFn = Rc<dyn Fn(BufferData)>;
diff --git a/core/io/unix.rs b/core/io/unix.rs
index cfe6d37fe..9cb50a3f8 100644
--- a/core/io/unix.rs
+++ b/core/io/unix.rs
@@ -450,6 +450,22 @@ impl File for UnixFile<'_> {
         let file = self.file.lock().unwrap();
         Ok(file.metadata()?.len())
     }
+
+    #[instrument(err, skip_all, level = Level::INFO)]
+    fn truncate(&self, len: usize, c: Completion) -> Result<Completion> {
+        let file = self.file.lock().map_err(|e| {
+            LimboError::LockingError(format!("Failed to lock file for truncation: {e}"))
+        })?;
+        let result = file.set_len(len as u64);
+        match result {
+            Ok(()) => {
+                trace!("file truncated to len=({})", len);
+                c.complete(0);
+                Ok(c)
+            }
+            Err(e) => Err(e.into()),
+        }
+    }
 }
 
 impl Drop for UnixFile<'_> {
diff --git a/core/io/vfs.rs b/core/io/vfs.rs
index 1f941e2c2..256ba4494 100644
--- a/core/io/vfs.rs
+++ b/core/io/vfs.rs
@@ -43,10 +43,8 @@ impl IO for VfsMod {
         Ok(())
     }
 
-    fn wait_for_completion(&self, c: Completion) -> Result<()> {
-        while !c.is_completed() {
-            self.run_once()?;
-        }
+    fn wait_for_completion(&self, _c: Completion) -> Result<()> {
+        // for the moment anyway, this is currently a sync api
         Ok(())
     }
 
@@ -165,6 +163,20 @@ impl File for VfsFileImpl {
             Ok(result as u64)
         }
     }
+
+    fn truncate(&self, len: usize, c: Completion) -> Result<Completion> {
+        if self.vfs.is_null() {
+            return Err(LimboError::ExtensionError("VFS is null".to_string()));
+        }
+        let vfs = unsafe { &*self.vfs };
+        let result = unsafe { (vfs.truncate)(self.file, len as i64) };
+        if result.is_error() {
+            Err(LimboError::ExtensionError("truncate failed".to_string()))
+        } else {
+            c.complete(0);
+            Ok(c)
+        }
+    }
 }
 
 impl Drop for VfsMod {
diff --git a/core/io/windows.rs b/core/io/windows.rs
index 701e61269..26d80cfc7 100644
--- a/core/io/windows.rs
+++ b/core/io/windows.rs
@@ -123,6 +123,13 @@ impl File for WindowsFile {
     }
 
     #[instrument(err, skip_all, level = Level::TRACE)]
+    fn truncate(&self, len: usize, c: Completion) -> Result<Completion> {
+        let file = self.file.write();
+        file.set_len(len as u64).map_err(LimboError::IOError)?;
+        c.complete(0);
+        Ok(c)
+    }
+
     fn size(&self) -> Result<u64> {
         let file = self.file.read();
         Ok(file.metadata().unwrap().len())
diff --git a/core/lib.rs b/core/lib.rs
index 2c1e73beb..6176e9811 100644
--- a/core/lib.rs
+++ b/core/lib.rs
@@ -103,6 +103,7 @@ pub type Result<T, E = LimboError> = std::result::Result<T, E>;
 enum TransactionState {
     Write { schema_did_change: bool },
     Read,
+    PendingUpgrade,
     None,
 }
 
@@ -311,9 +312,13 @@ impl Database {
 
             db.with_schema_mut(|schema| {
                 schema.schema_version = get_schema_version(&conn)?;
-                if let Err(LimboError::ExtensionError(e)) =
-                    schema.make_from_btree(None, pager, &syms)
-                {
+                let result = schema
+                    .make_from_btree(None, pager.clone(), &syms)
+                    .or_else(|e| {
+                        pager.end_read_tx()?;
+                        Err(e)
+                    });
+                if let Err(LimboError::ExtensionError(e)) = result {
                     // this means that a vtab exists and we no longer have the module loaded. we print
                     // a warning to the user to load the module
                     eprintln!("Warning: {e}");
@@ -1146,7 +1151,9 @@ impl Connection {
             result::LimboResult::Busy => return Err(LimboError::Busy),
             result::LimboResult::Ok => {}
         }
-        match pager.io.block(|| pager.begin_write_tx())? {
+        match pager.io.block(|| pager.begin_write_tx()).inspect_err(|_| {
+            pager.end_read_tx().expect("read txn must be closed");
+        })? {
             result::LimboResult::Busy => {
                 pager.end_read_tx().expect("read txn must be closed");
                 return Err(LimboError::Busy);
@@ -1163,12 +1170,13 @@ impl Connection {
         {
             let pager = self.pager.borrow();
 
+            {
+                let wal = pager.wal.borrow_mut();
+                wal.end_write_tx();
+                wal.end_read_tx();
+            }
             // remove all non-commited changes in case if WAL session left some suffix without commit frame
-            pager.rollback(false, self).expect("rollback must succeed");
-
-            let wal = pager.wal.borrow_mut();
-            wal.end_write_tx();
-            wal.end_read_tx();
+            pager.rollback(false, self)?;
         }
 
         // let's re-parse schema from scratch if schema cookie changed compared to the our in-memory view of schema
@@ -1188,13 +1196,13 @@ impl Connection {
         Ok(())
     }
 
-    pub fn checkpoint(&self) -> Result<CheckpointResult> {
+    pub fn checkpoint(&self, mode: CheckpointMode) -> Result<CheckpointResult> {
         if self.closed.get() {
             return Err(LimboError::InternalError("Connection closed".to_string()));
         }
         self.pager
             .borrow()
-            .wal_checkpoint(self.wal_checkpoint_disabled.get())
+            .wal_checkpoint(self.wal_checkpoint_disabled.get(), mode)
     }
 
     /// Close a connection and checkpoint.
@@ -1206,16 +1214,18 @@ impl Connection {
 
         match self.transaction_state.get() {
             TransactionState::Write { schema_did_change } => {
-                let _result = self.pager.borrow().end_tx(
+                while let IOResult::IO = self.pager.borrow().end_tx(
                     true, // rollback = true for close
                     schema_did_change,
                     self,
                     self.wal_checkpoint_disabled.get(),
-                );
+                )? {
+                    self.run_once()?;
+                }
                 self.transaction_state.set(TransactionState::None);
             }
-            TransactionState::Read => {
-                let _result = self.pager.borrow().end_read_tx();
+            TransactionState::PendingUpgrade | TransactionState::Read => {
+                self.pager.borrow().end_read_tx()?;
                 self.transaction_state.set(TransactionState::None);
             }
             TransactionState::None => {
@@ -1719,13 +1729,6 @@ impl Statement {
         if res.is_err() {
             let state = self.program.connection.transaction_state.get();
             if let TransactionState::Write { schema_did_change } = state {
-                if let Err(e) = self
-                    .pager
-                    .rollback(schema_did_change, &self.program.connection)
-                {
-                    // Let's panic for now as we don't want to leave state in a bad state.
-                    panic!("rollback failed: {e:?}");
-                }
                 let end_tx_res =
                     self.pager
                         .end_tx(true, schema_did_change, &self.program.connection, true)?;
diff --git a/core/result.rs b/core/result.rs
index 3056528ce..a13754b32 100644
--- a/core/result.rs
+++ b/core/result.rs
@@ -1,4 +1,5 @@
 /// Common results that different functions can return in limbo.
+#[derive(Debug)]
 pub enum LimboResult {
     /// Couldn't acquire a lock
     Busy,
diff --git a/core/storage/database.rs b/core/storage/database.rs
index 8e539a5f3..fd2555b59 100644
--- a/core/storage/database.rs
+++ b/core/storage/database.rs
@@ -18,6 +18,7 @@ pub trait DatabaseStorage: Send + Sync {
     ) -> Result<Completion>;
     fn sync(&self, c: Completion) -> Result<Completion>;
     fn size(&self) -> Result<u64>;
+    fn truncate(&self, len: usize, c: Completion) -> Result<Completion>;
 }
 
 #[cfg(feature = "fs")]
@@ -69,6 +70,12 @@ impl DatabaseStorage for DatabaseFile {
     fn size(&self) -> Result<u64> {
         self.file.size()
     }
+
+    #[instrument(skip_all, level = Level::INFO)]
+    fn truncate(&self, len: usize, c: Completion) -> Result<Completion> {
+        let c = self.file.truncate(len, c)?;
+        Ok(c)
+    }
 }
 
 #[cfg(feature = "fs")]
@@ -122,6 +129,12 @@ impl DatabaseStorage for FileMemoryStorage {
     fn size(&self) -> Result<u64> {
         self.file.size()
     }
+
+    #[instrument(skip_all, level = Level::INFO)]
+    fn truncate(&self, len: usize, c: Completion) -> Result<Completion> {
+        let c = self.file.truncate(len, c)?;
+        Ok(c)
+    }
 }
 
 impl FileMemoryStorage {
diff --git a/core/storage/pager.rs b/core/storage/pager.rs
index 3a73a96a1..a31094f19 100644
--- a/core/storage/pager.rs
+++ b/core/storage/pager.rs
@@ -4,12 +4,12 @@ use crate::storage::buffer_pool::BufferPool;
 use crate::storage::database::DatabaseStorage;
 use crate::storage::header_accessor;
 use crate::storage::sqlite3_ondisk::{
-    self, parse_wal_frame_header, DatabaseHeader, PageContent, PageType,
+    self, parse_wal_frame_header, DatabaseHeader, PageContent, PageType, DEFAULT_PAGE_SIZE,
 };
 use crate::storage::wal::{CheckpointResult, Wal};
 use crate::types::{IOResult, WalInsertInfo};
 use crate::util::IOExt as _;
-use crate::{return_if_io, Completion};
+use crate::{return_if_io, Completion, TransactionState};
 use crate::{turso_assert, Buffer, Connection, LimboError, Result};
 use parking_lot::RwLock;
 use std::cell::{Cell, OnceCell, RefCell, UnsafeCell};
@@ -351,7 +351,7 @@ pub struct Pager {
     free_page_state: RefCell<FreePageState>,
 }
 
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Clone)]
 /// The status of the current cache flush.
 pub enum PagerCommitResult {
     /// The WAL was written to disk and fsynced.
@@ -818,8 +818,14 @@ impl Pager {
     ) -> Result<IOResult<PagerCommitResult>> {
         tracing::trace!("end_tx(rollback={})", rollback);
         if rollback {
-            self.wal.borrow().end_write_tx();
+            if matches!(
+                connection.transaction_state.get(),
+                TransactionState::Write { .. }
+            ) {
+                self.wal.borrow().end_write_tx();
+            }
             self.wal.borrow().end_read_tx();
+            self.rollback(schema_did_change, connection)?;
             return Ok(IOResult::Done(PagerCommitResult::Rollback));
         }
         let commit_status = self.commit_dirty_pages(wal_checkpoint_disabled)?;
@@ -1283,26 +1289,51 @@ impl Pager {
                 _attempts += 1;
             }
         }
-        self.wal_checkpoint(wal_checkpoint_disabled)?;
+        self.wal_checkpoint(wal_checkpoint_disabled, CheckpointMode::Passive)?;
         Ok(())
     }
 
     #[instrument(skip_all, level = Level::DEBUG)]
-    pub fn wal_checkpoint(&self, wal_checkpoint_disabled: bool) -> Result<CheckpointResult> {
+    pub fn wal_checkpoint(
+        &self,
+        wal_checkpoint_disabled: bool,
+        mode: CheckpointMode,
+    ) -> Result<CheckpointResult> {
         if wal_checkpoint_disabled {
-            return Ok(CheckpointResult {
-                num_wal_frames: 0,
-                num_checkpointed_frames: 0,
-            });
+            return Ok(CheckpointResult::default());
         }
 
-        let checkpoint_result = self.io.block(|| {
+        let counter = Rc::new(RefCell::new(0));
+        let mut checkpoint_result = self.io.block(|| {
             self.wal
                 .borrow_mut()
-                .checkpoint(self, Rc::new(RefCell::new(0)), CheckpointMode::Passive)
-                .map_err(|err| panic!("error while clearing cache {err}"))
+                .checkpoint(self, counter.clone(), mode)
         })?;
 
+        if checkpoint_result.everything_backfilled()
+            && checkpoint_result.num_checkpointed_frames != 0
+        {
+            let db_size = header_accessor::get_database_size(self)?;
+            let page_size = self.page_size.get().unwrap_or(DEFAULT_PAGE_SIZE);
+            let expected = (db_size * page_size) as u64;
+            if expected < self.db_file.size()? {
+                self.io.wait_for_completion(self.db_file.truncate(
+                    expected as usize,
+                    Completion::new_trunc(move |_| {
+                        tracing::trace!(
+                            "Database file truncated to expected size: {} bytes",
+                            expected
+                        );
+                    }),
+                )?)?;
+                self.io
+                    .wait_for_completion(self.db_file.sync(Completion::new_sync(move |_| {
+                        tracing::trace!("Database file syncd after truncation");
+                    }))?)?;
+            }
+            checkpoint_result.release_guard();
+        }
+
         // TODO: only clear cache of things that are really invalidated
         self.page_cache
             .write()
diff --git a/core/storage/sqlite3_ondisk.rs b/core/storage/sqlite3_ondisk.rs
index 46cb738b4..829f049b6 100644
--- a/core/storage/sqlite3_ondisk.rs
+++ b/core/storage/sqlite3_ondisk.rs
@@ -1695,7 +1695,8 @@ pub fn begin_write_wal_header(io: &Arc<dyn File>, header: &WalHeader) -> Result<
     };
     #[allow(clippy::arc_with_non_send_sync)]
     let c = Completion::new_write(write_complete);
-    io.pwrite(0, buffer.clone(), c)
+    let c = io.pwrite(0, buffer.clone(), c.clone())?;
+    Ok(c)
 }
 
 /// Checks if payload will overflow a cell based on the maximum allowed size.
diff --git a/core/storage/wal.rs b/core/storage/wal.rs
index c166d8017..eb55e9dc2 100644
--- a/core/storage/wal.rs
+++ b/core/storage/wal.rs
@@ -39,12 +39,23 @@ pub const NO_LOCK: u32 = 0;
 pub const SHARED_LOCK: u32 = 1;
 pub const WRITE_LOCK: u32 = 2;
 
-#[derive(Debug, Copy, Clone, Default)]
+const NO_LOCK_HELD: usize = usize::MAX;
+
+#[derive(Debug, Clone, Default)]
 pub struct CheckpointResult {
     /// number of frames in WAL
     pub num_wal_frames: u64,
     /// number of frames moved successfully from WAL to db file after checkpoint
     pub num_checkpointed_frames: u64,
+    /// In the case of everything backfilled, we need to hold the locks until the db
+    /// file is truncated.
+    maybe_guard: Option<CheckpointLocks>,
+}
+
+impl Drop for CheckpointResult {
+    fn drop(&mut self) {
+        let _ = self.maybe_guard.take();
+    }
 }
 
 impl CheckpointResult {
@@ -52,14 +63,23 @@ impl CheckpointResult {
         Self {
             num_wal_frames: n_frames,
             num_checkpointed_frames: n_ckpt,
+            maybe_guard: None,
         }
     }
+
+    pub const fn everything_backfilled(&self) -> bool {
+        self.num_wal_frames == self.num_checkpointed_frames
+    }
+    pub fn release_guard(&mut self) {
+        let _ = self.maybe_guard.take();
+    }
 }
 
 #[derive(Debug, Copy, Clone, EnumString)]
 #[strum(ascii_case_insensitive)]
 pub enum CheckpointMode {
     /// Checkpoint as many frames as possible without waiting for any database readers or writers to finish, then sync the database file if all frames in the log were checkpointed.
+    /// Passive never blocks readers or writers, only ensures (like all modes do) that there are no other checkpointers.
     Passive,
     /// This mode blocks until there is no database writer and all readers are reading from the most recent database snapshot. It then checkpoints all frames in the log file and syncs the database file. This mode blocks new database writers while it is pending, but new database readers are allowed to continue unimpeded.
     Full,
@@ -255,6 +275,9 @@ pub trait Wal {
     fn get_max_frame(&self) -> u64;
     fn get_min_frame(&self) -> u64;
     fn rollback(&mut self) -> Result<()>;
+
+    #[cfg(debug_assertions)]
+    fn as_any(&self) -> &dyn std::any::Any;
 }
 
 /// A dummy WAL implementation that does nothing.
@@ -351,6 +374,10 @@ impl Wal for DummyWAL {
     fn rollback(&mut self) -> Result<()> {
         Ok(())
     }
+    #[cfg(debug_assertions)]
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
 }
 
 // Syncing requires a state machine because we need to schedule a sync and then wait until it is
@@ -412,7 +439,7 @@ pub struct WalFile {
     // min and max frames for this connection
     /// This is the index to the read_lock in WalFileShared that we are holding. This lock contains
     /// the max frame for this connection.
-    max_frame_read_lock_index: usize,
+    max_frame_read_lock_index: Cell<usize>,
     /// Max frame allowed to lookup range=(minframe..max_frame)
     max_frame: u64,
     /// Start of range to look for frames range=(minframe..max_frame)
@@ -428,6 +455,9 @@ pub struct WalFile {
 
     /// Private copy of WalHeader
     pub header: WalHeader,
+
+    /// Manages locks needed for checkpointing
+    checkpoint_guard: Option<CheckpointLocks>,
 }
 
 impl fmt::Debug for WalFile {
@@ -447,6 +477,61 @@ impl fmt::Debug for WalFile {
     }
 }
 
+/*
+* sqlite3/src/wal.c
+*
+** nBackfill is the number of frames in the WAL that have been written
+** back into the database. (We call the act of moving content from WAL to
+** database "backfilling".)  The nBackfill number is never greater than
+** WalIndexHdr.mxFrame.  nBackfill can only be increased by threads
+** holding the WAL_CKPT_LOCK lock (which includes a recovery thread).
+** However, a WAL_WRITE_LOCK thread can move the value of nBackfill from
+** mxFrame back to zero when the WAL is reset.
+**
+** nBackfillAttempted is the largest value of nBackfill that a checkpoint
+** has attempted to achieve.  Normally nBackfill==nBackfillAtempted, however
+** the nBackfillAttempted is set before any backfilling is done and the
+** nBackfill is only set after all backfilling completes.  So if a checkpoint
+** crashes, nBackfillAttempted might be larger than nBackfill.  The
+** WalIndexHdr.mxFrame must never be less than nBackfillAttempted.
+**
+** The aLock[] field is a set of bytes used for locking.  These bytes should
+** never be read or written.
+**
+** There is one entry in aReadMark[] for each reader lock.  If a reader
+** holds read-lock K, then the value in aReadMark[K] is no greater than
+** the mxFrame for that reader.  The value READMARK_NOT_USED (0xffffffff)
+** for any aReadMark[] means that entry is unused.  aReadMark[0] is
+** a special case; its value is never used and it exists as a place-holder
+** to avoid having to offset aReadMark[] indexes by one.  Readers holding
+** WAL_READ_LOCK(0) always ignore the entire WAL and read all content
+** directly from the database.
+**
+** The value of aReadMark[K] may only be changed by a thread that
+** is holding an exclusive lock on WAL_READ_LOCK(K).  Thus, the value of
+** aReadMark[K] cannot changed while there is a reader is using that mark
+** since the reader will be holding a shared lock on WAL_READ_LOCK(K).
+**
+** The checkpointer may only transfer frames from WAL to database where
+** the frame numbers are less than or equal to every aReadMark[] that is
+** in use (that is, every aReadMark[j] for which there is a corresponding
+** WAL_READ_LOCK(j)).  New readers (usually) pick the aReadMark[] with the
+** largest value and will increase an unused aReadMark[] to mxFrame if there
+** is not already an aReadMark[] equal to mxFrame.  The exception to the
+** previous sentence is when nBackfill equals mxFrame (meaning that everything
+** in the WAL has been backfilled into the database) then new readers
+** will choose aReadMark[0] which has value 0 and hence such reader will
+** get all their all content directly from the database file and ignore
+** the WAL.
+**
+** Writers normally append new frames to the end of the WAL.  However,
+** if nBackfill equals mxFrame (meaning that all WAL content has been
+** written back into the database) and if no readers are using the WAL
+** (in other words, if there are no WAL_READ_LOCK(i) where i>0) then
+** the writer will first "reset" the WAL back to the beginning and start
+** writing new content beginning at frame 1.
+*/
+
 // TODO(pere): lock only important parts + pin WalFileShared
 /// WalFileShared is the part of a WAL that will be shared between threads. A wal has information
 /// that needs to be communicated between threads so this struct does the job.
@@ -467,14 +552,19 @@ pub struct WalFileShared {
     pub pages_in_frames: Arc<SpinLock<Vec<u64>>>,
     pub last_checksum: (u32, u32), // Check of last frame in WAL, this is a cumulative checksum over all frames in the WAL
     pub file: Arc<dyn File>,
-    /// read_locks is a list of read locks that can coexist with the max_frame number stored in
-    /// value. There is a limited amount because and unbounded amount of connections could be
-    /// fatal. Therefore, for now we copy how SQLite behaves with limited amounts of read max
-    /// frames that is equal to 5
+
+    /// Read locks advertise the maximum WAL frame a reader may access.
+    /// Slot 0 is special, when it is held (shared) the reader bypasses the WAL and uses the main DB file.
+    /// When checkpointing, we must acquire the exclusive read lock 0 to ensure that no readers read
+    /// from a partially checkpointed db file.
+    /// Slots 1‑4 carry a frame‑number in value and may be shared by many readers. Slot 1 is the
+    /// default read lock and is to contain the max_frame in WAL.
     pub read_locks: [LimboRwLock; 5],
     /// There is only one write allowed in WAL mode. This lock takes care of ensuring there is only
     /// one used.
     pub write_lock: LimboRwLock,
+
+    /// Serialises checkpointer threads, only one checkpoint can be in flight at any time. Blocking and exclusive only
     pub checkpoint_lock: LimboRwLock,
     pub loaded: AtomicBool,
 }
@@ -494,101 +584,269 @@ impl fmt::Debug for WalFileShared {
     }
 }
 
+#[derive(Clone, Debug)]
+/// To manage and ensure that no locks are leaked during checkpointing in
+/// the case of errors. It is held by the WalFile while checkpoint is ongoing
+/// then transferred to the CheckpointResult if necessary.
+enum CheckpointLocks {
+    Writer { ptr: Arc<UnsafeCell<WalFileShared>> },
+    Read0 { ptr: Arc<UnsafeCell<WalFileShared>> },
+}
+
+/// Database checkpointers takes the following locks, in order:
+/// The exclusive CHECKPOINTER lock.
+/// The exclusive WRITER lock (FULL, RESTART and TRUNCATE only).
+/// Exclusive lock on read-mark slots 1-N. These are immediately released after being taken.
+/// Exclusive lock on read-mark 0.
+/// Exclusive lock on read-mark slots 1-N again. These are immediately released after being taken (RESTART and TRUNCATE only).
+/// All of the above use blocking locks.
+impl CheckpointLocks {
+    fn new(ptr: Arc<UnsafeCell<WalFileShared>>, mode: CheckpointMode) -> Result<Self> {
+        let shared = &mut unsafe { &mut *ptr.get() };
+        if !shared.checkpoint_lock.write() {
+            tracing::trace!("CheckpointGuard::new: checkpoint lock failed, returning Busy");
+            // we hold the exclusive checkpoint lock no matter which mode for the duration
+            return Err(LimboError::Busy);
+        }
+        match mode {
+            CheckpointMode::Full => Err(LimboError::InternalError(
+                "Full checkpoint mode is not yet supported".into(),
+            )),
+            // Passive mode is the only mode not requiring a write lock, as it doesn't block
+            // readers or writers. It acquires the checkpoint lock to ensure that no other
+            // concurrent checkpoint happens, and acquires the exclusive read lock 0
+            // to ensure that no readers read from a partially checkpointed db file.
+            CheckpointMode::Passive => {
+                let read0 = &mut shared.read_locks[0];
+                if !read0.write() {
+                    shared.checkpoint_lock.unlock();
+                    tracing::trace!("CheckpointGuard: read0 lock failed, returning Busy");
+                    // for passive and full we need to hold the read0 lock
+                    return Err(LimboError::Busy);
+                }
+                Ok(Self::Read0 { ptr })
+            }
+            CheckpointMode::Restart | CheckpointMode::Truncate => {
+                // like all modes, we must acquire an exclusive checkpoint lock and lock on read 0
+                // to prevent a reader from reading a partially checkpointed db file.
+                let read0 = &mut shared.read_locks[0];
+                if !read0.write() {
+                    shared.checkpoint_lock.unlock();
+                    tracing::trace!("CheckpointGuard: read0 lock failed, returning Busy");
+                    return Err(LimboError::Busy);
+                }
+                // if we are resetting the log we must hold the write lock for the duration.
+                // ensures no writer can append frames while we reset the log.
+                if !shared.write_lock.write() {
+                    shared.checkpoint_lock.unlock();
+                    read0.unlock();
+                    tracing::trace!("CheckpointGuard: write lock failed, returning Busy");
+                    return Err(LimboError::Busy);
+                }
+                Ok(Self::Writer { ptr })
+            }
+        }
+    }
+}
+
+impl Drop for CheckpointLocks {
+    fn drop(&mut self) {
+        match self {
+            CheckpointLocks::Writer { ptr: shared } => unsafe {
+                (*shared.get()).write_lock.unlock();
+                (*shared.get()).read_locks[0].unlock();
+                (*shared.get()).checkpoint_lock.unlock();
+            },
+            CheckpointLocks::Read0 { ptr: shared } => unsafe {
+                (*shared.get()).read_locks[0].unlock();
+                (*shared.get()).checkpoint_lock.unlock();
+            },
+        }
+    }
+}
+
 impl Wal for WalFile {
-    /// Begin a read transaction.
+    /// Begin a read transaction. The caller must ensure that there is not already
+    /// an ongoing read transaction.
+    /// sqlite/src/wal.c 3023
+    /// assert(pWal->readLock < 0); /* Not currently locked */
     #[instrument(skip_all, level = Level::DEBUG)]
     fn begin_read_tx(&mut self) -> Result<(LimboResult, bool)> {
-        let max_frame_in_wal = self.get_shared().max_frame.load(Ordering::SeqCst);
-
-        let db_has_changed = max_frame_in_wal > self.max_frame;
-
-        let mut max_read_mark = 0;
-        let mut max_read_mark_index = -1;
-        // Find the largest mark we can find, ignore frames that are impossible to be in range and
-        // that are not set
-        for (index, lock) in self.get_shared().read_locks.iter().enumerate() {
-            let this_mark = lock.value.load(Ordering::SeqCst);
-            if this_mark > max_read_mark && this_mark <= max_frame_in_wal as u32 {
-                max_read_mark = this_mark;
-                max_read_mark_index = index as i64;
-            }
-        }
-
-        // If we didn't find any mark or we can update, let's update them
-        if (max_read_mark as u64) < max_frame_in_wal || max_read_mark_index == -1 {
-            for (index, lock) in self.get_shared().read_locks.iter_mut().enumerate() {
-                let busy = !lock.write();
-                if !busy {
-                    // If this was busy then it must mean >1 threads tried to set this read lock
-                    lock.value.store(max_frame_in_wal as u32, Ordering::SeqCst);
-                    max_read_mark = max_frame_in_wal as u32;
-                    max_read_mark_index = index as i64;
-                    lock.unlock();
-                    break;
-                }
-            }
-        }
-
-        if max_read_mark_index == -1 {
-            return Ok((LimboResult::Busy, db_has_changed));
-        }
-
-        let (min_frame, last_checksum, start_pages_in_frames) = {
+        turso_assert!(
+            self.max_frame_read_lock_index.get().eq(&NO_LOCK_HELD),
+            "cannot start a new read tx without ending an existing one, lock_value={}, expected={}",
+            self.max_frame_read_lock_index.get(),
+            NO_LOCK_HELD
+        );
+        let (shared_max, nbackfills, last_checksum, checkpoint_seq) = {
             let shared = self.get_shared();
-            let lock = &mut shared.read_locks[max_read_mark_index as usize];
-            tracing::trace!("begin_read_tx_read_lock(lock={})", max_read_mark_index);
-            let busy = !lock.read();
-            if busy {
-                return Ok((LimboResult::Busy, db_has_changed));
+            let mx = shared.max_frame.load(Ordering::SeqCst);
+            let nb = shared.nbackfills.load(Ordering::SeqCst);
+            let ck = shared.last_checksum;
+            let checkpoint_seq = shared.wal_header.lock().checkpoint_seq;
+            (mx, nb, ck, checkpoint_seq)
+        };
+        let db_changed = shared_max > self.max_frame;
+
+        // WAL is already fully back‑filled into the main DB image
+        // (mxFrame == nBackfill). Readers can therefore ignore the
+        // WAL and fetch pages directly from the DB file.  We do this
+        // by taking read‑lock 0, and capturing the latest state.
+        if shared_max == nbackfills {
+            let lock_idx = 0;
+            if !self.get_shared().read_locks[lock_idx].read() {
+                return Ok((LimboResult::Busy, db_changed));
+            }
+            // we need to keep self.max_frame set to the appropriate
+            // max frame in the wal at the time this transaction starts.
+            self.max_frame = shared_max;
+            self.max_frame_read_lock_index.set(lock_idx);
+            self.min_frame = nbackfills + 1;
+            self.last_checksum = last_checksum;
+            return Ok((LimboResult::Ok, db_changed));
+        }
+
+        // If we get this far, it means that the reader will want to use
+        // the WAL to get at content from recent commits.  The job now is
+        // to select one of the aReadMark[] entries that is closest to
+        // but not exceeding pWal->hdr.mxFrame and lock that entry.
+        // Find largest mark <= mx among slots 1..N
+        let mut best_idx: i64 = -1;
+        let mut best_mark: u32 = 0;
+        for (idx, lock) in self.get_shared().read_locks.iter().enumerate().skip(1) {
+            let m = lock.value.load(Ordering::SeqCst);
+            if m != READMARK_NOT_USED && m <= shared_max as u32 && m > best_mark {
+                best_mark = m;
+                best_idx = idx as i64;
+            }
+        }
+
+        // If none found or lagging, try to claim/update a slot
+        if best_idx == -1 || (best_mark as u64) < shared_max {
+            for (idx, lock) in self.get_shared().read_locks.iter_mut().enumerate().skip(1) {
+                if !lock.write() {
+                    continue; // busy slot
+                }
+                // claim or bump this slot
+                lock.value.store(shared_max as u32, Ordering::SeqCst);
+                best_idx = idx as i64;
+                best_mark = shared_max as u32;
+                lock.unlock();
+                break;
+            }
+        }
+
+        if best_idx == -1 {
+            return Ok((LimboResult::Busy, db_changed));
+        }
+
+        // Now take a shared read on that slot, and if we are successful,
+        // grab another snapshot of the shared state.
+        let (mx2, nb2, cksm2, start_pages, ckpt_seq2) = {
+            let shared = self.get_shared();
+            if !shared.read_locks[best_idx as usize].read() {
+                // TODO: we should retry here instead of always returning Busy
+                return Ok((LimboResult::Busy, db_changed));
             }
             (
-                shared.nbackfills.load(Ordering::SeqCst) + 1,
+                shared.max_frame.load(Ordering::SeqCst),
+                shared.nbackfills.load(Ordering::SeqCst),
                 shared.last_checksum,
                 shared.pages_in_frames.lock().len(),
+                shared.wal_header.lock().checkpoint_seq,
             )
         };
-        self.min_frame = min_frame;
-        self.max_frame_read_lock_index = max_read_mark_index as usize;
-        self.max_frame = max_read_mark as u64;
-        self.last_checksum = last_checksum;
-        self.start_pages_in_frames = start_pages_in_frames;
+
+        // sqlite/src/wal.c 3225
+        // Now that the read-lock has been obtained, check that neither the
+        // value in the aReadMark[] array or the contents of the wal-index
+        // header have changed.
+        //
+        // It is necessary to check that the wal-index header did not change
+        // between the time it was read and when the shared-lock was obtained
+        // on WAL_READ_LOCK(mxI) was obtained to account for the possibility
+        // that the log file may have been wrapped by a writer, or that frames
+        // that occur later in the log than pWal->hdr.mxFrame may have been
+        // copied into the database by a checkpointer. If either of these things
+        // happened, then reading the database with the current value of
+        // pWal->hdr.mxFrame risks reading a corrupted snapshot. So, retry
+        // instead.
+        //
+        // Before checking that the live wal-index header has not changed
+        // since it was read, set Wal.minFrame to the first frame in the wal
+        // file that has not yet been checkpointed. This client will not need
+        // to read any frames earlier than minFrame from the wal file - they
+        // can be safely read directly from the database file.
+        self.min_frame = nb2 + 1;
+        if mx2 != shared_max
+            || nb2 != nbackfills
+            || cksm2 != last_checksum
+            || ckpt_seq2 != checkpoint_seq
+        {
+            return Err(LimboError::Busy);
+        }
+        self.max_frame = best_mark as u64;
+        self.start_pages_in_frames = start_pages;
+        self.max_frame_read_lock_index.set(best_idx as usize);
         tracing::debug!(
-            "begin_read_tx(min_frame={}, max_frame={}, lock={}, max_frame_in_wal={})",
+            "begin_read_tx(min={}, max={}, slot={}, max_frame_in_wal={})",
             self.min_frame,
             self.max_frame,
-            self.max_frame_read_lock_index,
-            max_frame_in_wal
+            best_idx,
+            shared_max
         );
-        Ok((LimboResult::Ok, db_has_changed))
+        Ok((LimboResult::Ok, db_changed))
     }
 
     /// End a read transaction.
     #[inline(always)]
     #[instrument(skip_all, level = Level::DEBUG)]
     fn end_read_tx(&self) {
-        tracing::debug!("end_read_tx(lock={})", self.max_frame_read_lock_index);
-        let read_lock = &mut self.get_shared().read_locks[self.max_frame_read_lock_index];
-        read_lock.unlock();
+        let slot = self.max_frame_read_lock_index.get();
+        if slot != NO_LOCK_HELD {
+            let rl = &mut self.get_shared().read_locks[slot];
+            rl.unlock();
+            self.max_frame_read_lock_index.set(NO_LOCK_HELD);
+            tracing::debug!("end_read_tx(slot={slot})");
+        } else {
+            tracing::debug!("end_read_tx(slot=no_lock)");
+        }
     }
 
     /// Begin a write transaction
     #[instrument(skip_all, level = Level::DEBUG)]
     fn begin_write_tx(&mut self) -> Result<LimboResult> {
-        let busy = !self.get_shared().write_lock.write();
-        tracing::debug!("begin_write_transaction(busy={})", busy);
-        if busy {
-            return Ok(LimboResult::Busy);
-        }
-        // If the max frame is not the same as the one in the shared state, it means another
-        // transaction wrote to the WAL after we started our read transaction. This means our
-        // snapshot is not consistent with the one in the shared state and we need to start another
-        // one.
         let shared = self.get_shared();
-        if self.max_frame != shared.max_frame.load(Ordering::SeqCst) {
-            shared.write_lock.unlock();
+        // sqlite/src/wal.c 3702
+        // Cannot start a write transaction without first holding a read
+        // transaction.
+        // assert(pWal->readLock >= 0);
+        // assert(pWal->writeLock == 0 && pWal->iReCksum == 0);
+        turso_assert!(
+            self.max_frame_read_lock_index.get() != NO_LOCK_HELD,
+            "must have a read transaction to begin a write transaction"
+        );
+        if !shared.write_lock.write() {
             return Ok(LimboResult::Busy);
         }
-        Ok(LimboResult::Ok)
+        let (shared_max, nbackfills, last_checksum) = {
+            let shared = self.get_shared();
+            (
+                shared.max_frame.load(Ordering::SeqCst),
+                shared.nbackfills.load(Ordering::SeqCst),
+                shared.last_checksum,
+            )
+        };
+        if self.max_frame == shared_max {
+            // Snapshot still valid; adopt counters
+            self.last_checksum = last_checksum;
+            self.min_frame = nbackfills + 1;
+            return Ok(LimboResult::Ok);
+        }
+
+        // Snapshot is stale, give up and let caller retry from scratch
+        shared.write_lock.unlock();
+        Ok(LimboResult::Busy)
     }
 
     /// End a write transaction
@@ -601,16 +859,16 @@ impl Wal for WalFile {
     /// Find the latest frame containing a page.
     #[instrument(skip_all, level = Level::DEBUG)]
     fn find_frame(&self, page_id: u64) -> Result<Option<u64>> {
-        let shared = self.get_shared();
-        let frames = shared.frame_cache.lock();
-        let frames = frames.get(&page_id);
-        if frames.is_none() {
+        // if we are holding read_lock 0, skip and read right from db file.
+        if self.max_frame_read_lock_index.get() == 0 {
             return Ok(None);
         }
-        let frames = frames.unwrap();
-        for frame in frames.iter().rev() {
-            if *frame <= self.max_frame {
-                return Ok(Some(*frame));
+        let shared = self.get_shared();
+        let frames = shared.frame_cache.lock();
+        let range = self.min_frame..=self.max_frame;
+        if let Some(list) = frames.get(&page_id) {
+            if let Some(f) = list.iter().rfind(|&&f| range.contains(&f)) {
+                return Ok(Some(*f));
             }
         }
         Ok(None)
@@ -759,6 +1017,10 @@ impl Wal for WalFile {
         db_size: u32,
         write_counter: Rc<RefCell<usize>>,
     ) -> Result<Completion> {
+        let shared = self.get_shared();
+        if shared.max_frame.load(Ordering::SeqCst).eq(&0) {
+            self.ensure_header_if_needed()?;
+        }
         let page_id = page.get().id;
         let frame_id = self.max_frame + 1;
         let offset = self.frame_offset(frame_id);
@@ -820,183 +1082,15 @@ impl Wal for WalFile {
         write_counter: Rc<RefCell<usize>>,
         mode: CheckpointMode,
     ) -> Result<IOResult<CheckpointResult>> {
-        assert!(
-            matches!(mode, CheckpointMode::Passive),
-            "only passive mode supported for now"
-        );
-        'checkpoint_loop: loop {
-            let state = self.ongoing_checkpoint.state;
-            tracing::debug!(?state);
-            match state {
-                CheckpointState::Start => {
-                    // TODO(pere): check what frames are safe to checkpoint between many readers!
-                    let (shared_max, nbackfills) = {
-                        let shared = self.get_shared();
-                        (
-                            shared.max_frame.load(Ordering::SeqCst),
-                            shared.nbackfills.load(Ordering::SeqCst),
-                        )
-                    };
-                    if shared_max <= nbackfills {
-                        // if there's nothing to do and we are fully back-filled, to match sqlite
-                        // we return the previous number of backfilled pages from last checkpoint.
-                        return Ok(IOResult::Done(self.prev_checkpoint));
-                    }
-                    self.ongoing_checkpoint.min_frame = nbackfills + 1;
-                    let shared = self.get_shared();
-                    let busy = !shared.checkpoint_lock.write();
-                    if busy {
-                        return Err(LimboError::Busy);
-                    }
-                    let mut max_safe_frame = shared.max_frame.load(Ordering::SeqCst);
-                    for (read_lock_idx, read_lock) in shared.read_locks.iter_mut().enumerate() {
-                        let this_mark = read_lock.value.load(Ordering::SeqCst);
-                        if this_mark < max_safe_frame as u32 {
-                            let busy = !read_lock.write();
-                            if !busy {
-                                let new_mark = if read_lock_idx == 0 {
-                                    max_safe_frame as u32
-                                } else {
-                                    READMARK_NOT_USED
-                                };
-                                read_lock.value.store(new_mark, Ordering::SeqCst);
-                                read_lock.unlock();
-                            } else {
-                                max_safe_frame = this_mark as u64;
-                            }
-                        }
-                    }
-                    self.ongoing_checkpoint.max_frame = max_safe_frame;
-                    self.ongoing_checkpoint.current_page = 0;
-                    self.ongoing_checkpoint.state = CheckpointState::ReadFrame;
-                    tracing::trace!(
-                        "checkpoint_start(min_frame={}, max_frame={})",
-                        self.ongoing_checkpoint.min_frame,
-                        self.ongoing_checkpoint.max_frame,
-                    );
-                }
-                CheckpointState::ReadFrame => {
-                    let shared = self.get_shared();
-                    let min_frame = self.ongoing_checkpoint.min_frame;
-                    let max_frame = self.ongoing_checkpoint.max_frame;
-                    let pages_in_frames = shared.pages_in_frames.clone();
-                    let pages_in_frames = pages_in_frames.lock();
-
-                    let frame_cache = shared.frame_cache.clone();
-                    let frame_cache = frame_cache.lock();
-                    assert!(self.ongoing_checkpoint.current_page as usize <= pages_in_frames.len());
-                    if self.ongoing_checkpoint.current_page as usize == pages_in_frames.len() {
-                        self.ongoing_checkpoint.state = CheckpointState::Done;
-                        continue 'checkpoint_loop;
-                    }
-                    let page = pages_in_frames[self.ongoing_checkpoint.current_page as usize];
-                    let frames = frame_cache
-                        .get(&page)
-                        .expect("page must be in frame cache if it's in list");
-
-                    for frame in frames.iter().rev() {
-                        if *frame >= min_frame && *frame <= max_frame {
-                            tracing::debug!(
-                                "checkpoint page(state={:?}, page={}, frame={})",
-                                state,
-                                page,
-                                *frame
-                            );
-                            self.ongoing_checkpoint.page.get().id = page as usize;
-
-                            let c = self.read_frame(
-                                *frame,
-                                self.ongoing_checkpoint.page.clone(),
-                                self.buffer_pool.clone(),
-                            )?;
-                            self.ongoing_checkpoint.state = CheckpointState::WaitReadFrame;
-                            continue 'checkpoint_loop;
-                        }
-                    }
-                    self.ongoing_checkpoint.current_page += 1;
-                }
-                CheckpointState::WaitReadFrame => {
-                    if self.ongoing_checkpoint.page.is_locked() {
-                        return Ok(IOResult::IO);
-                    } else {
-                        self.ongoing_checkpoint.state = CheckpointState::WritePage;
-                    }
-                }
-                CheckpointState::WritePage => {
-                    self.ongoing_checkpoint.page.set_dirty();
-                    let c = begin_write_btree_page(
-                        pager,
-                        &self.ongoing_checkpoint.page,
-                        write_counter.clone(),
-                    )?;
-                    self.ongoing_checkpoint.state = CheckpointState::WaitWritePage;
-                }
-                CheckpointState::WaitWritePage => {
-                    if *write_counter.borrow() > 0 {
-                        return Ok(IOResult::IO);
-                    }
-                    // If page was in cache clear it.
-                    if let Some(page) = pager.cache_get(self.ongoing_checkpoint.page.get().id) {
-                        page.clear_dirty();
-                    }
-                    self.ongoing_checkpoint.page.clear_dirty();
-                    let shared = self.get_shared();
-                    if (self.ongoing_checkpoint.current_page as usize)
-                        < shared.pages_in_frames.lock().len()
-                    {
-                        self.ongoing_checkpoint.current_page += 1;
-                        self.ongoing_checkpoint.state = CheckpointState::ReadFrame;
-                    } else {
-                        self.ongoing_checkpoint.state = CheckpointState::Done;
-                    }
-                }
-                CheckpointState::Done => {
-                    if *write_counter.borrow() > 0 {
-                        return Ok(IOResult::IO);
-                    }
-                    let shared = self.get_shared();
-                    shared.checkpoint_lock.unlock();
-                    let max_frame = shared.max_frame.load(Ordering::SeqCst);
-                    let nbackfills = shared.nbackfills.load(Ordering::SeqCst);
-
-                    // Record two num pages fields to return as checkpoint result to caller.
-                    // Ref: pnLog, pnCkpt on https://www.sqlite.org/c3ref/wal_checkpoint_v2.html
-                    let frames_in_wal = max_frame.saturating_sub(nbackfills);
-                    let frames_checkpointed = self
-                        .ongoing_checkpoint
-                        .max_frame
-                        .saturating_sub(self.ongoing_checkpoint.min_frame - 1);
-                    let checkpoint_result =
-                        CheckpointResult::new(frames_in_wal, frames_checkpointed);
-                    let everything_backfilled = shared.max_frame.load(Ordering::SeqCst)
-                        == self.ongoing_checkpoint.max_frame;
-                    shared
-                        .nbackfills
-                        .store(self.ongoing_checkpoint.max_frame, Ordering::SeqCst);
-                    if everything_backfilled {
-                        // TODO: Even in Passive mode, if everything was backfilled we should
-                        // truncate and fsync the *db file*
-
-                        // To properly reset the *wal file* we will need restart and/or truncate mode.
-                        // Currently, it will grow the WAL file indefinetly, but don't resetting is better than breaking.
-                        // Check: https://github.com/sqlite/sqlite/blob/2bd9f69d40dd240c4122c6d02f1ff447e7b5c098/src/wal.c#L2193
-                        if !matches!(mode, CheckpointMode::Passive) {
-                            // Here we know that we backfilled everything, therefore we can safely
-                            // reset the wal.
-                            shared.frame_cache.lock().clear();
-                            shared.pages_in_frames.lock().clear();
-                            shared.max_frame.store(0, Ordering::SeqCst);
-                            shared.nbackfills.store(0, Ordering::SeqCst);
-                            // TODO: if all frames were backfilled into the db file, calls fsync
-                            // TODO(pere): truncate wal file here.
-                        }
-                    }
-                    self.prev_checkpoint = checkpoint_result;
-                    self.ongoing_checkpoint.state = CheckpointState::Start;
-                    return Ok(IOResult::Done(checkpoint_result));
-                }
-            }
+        if matches!(mode, CheckpointMode::Full) {
+            return Err(LimboError::InternalError(
+                "Full checkpoint mode is not implemented yet".into(),
+            ));
         }
+        self.checkpoint_inner(pager, write_counter, mode)
+            .inspect_err(|_| {
+                let _ = self.checkpoint_guard.take();
+            })
     }
 
     #[instrument(err, skip_all, level = Level::DEBUG)]
@@ -1011,7 +1105,7 @@ impl Wal for WalFile {
                     syncing.set(false);
                 });
                 let shared = self.get_shared();
-                let c = shared.file.sync(completion)?;
+                let _c = shared.file.sync(completion)?;
                 self.sync_state.set(SyncState::Syncing);
                 Ok(IOResult::IO)
             }
@@ -1077,6 +1171,10 @@ impl Wal for WalFile {
         shared.last_checksum = self.last_checksum;
         Ok(())
     }
+    #[cfg(debug_assertions)]
+    fn as_any(&self) -> &dyn std::any::Any {
+        self
+    }
 }
 
 impl WalFile {
@@ -1117,9 +1215,10 @@ impl WalFile {
             syncing: Rc::new(Cell::new(false)),
             sync_state: Cell::new(SyncState::NotSyncing),
             min_frame: 0,
-            max_frame_read_lock_index: 0,
+            max_frame_read_lock_index: NO_LOCK_HELD.into(),
             last_checksum,
             prev_checkpoint: CheckpointResult::default(),
+            checkpoint_guard: None,
             start_pages_in_frames: 0,
             header: *header,
         }
@@ -1163,9 +1262,403 @@ impl WalFile {
         self.ongoing_checkpoint.min_frame = 0;
         self.ongoing_checkpoint.max_frame = 0;
         self.ongoing_checkpoint.current_page = 0;
+        self.max_frame_read_lock_index.set(NO_LOCK_HELD);
         self.sync_state.set(SyncState::NotSyncing);
         self.syncing.set(false);
     }
+
+    /// the WAL file has been truncated and we are writing the first
+    /// frame since then. We need to ensure that the header is initialized.
+    fn ensure_header_if_needed(&mut self) -> Result<()> {
+        tracing::debug!("ensure_header_if_needed");
+        self.last_checksum = {
+            let shared = self.get_shared();
+            if shared.max_frame.load(Ordering::SeqCst) != 0 {
+                return Ok(());
+            }
+            if shared.file.size()? >= WAL_HEADER_SIZE as u64 {
+                return Ok(());
+            }
+
+            let mut hdr = shared.wal_header.lock();
+            if hdr.page_size == 0 {
+                hdr.page_size = self.page_size();
+            }
+
+            // recompute header checksum
+            let prefix = &hdr.as_bytes()[..WAL_HEADER_SIZE - 8];
+            let use_native = (hdr.magic & 1) != 0;
+            let (c1, c2) = checksum_wal(prefix, &hdr, (0, 0), use_native);
+            hdr.checksum_1 = c1;
+            hdr.checksum_2 = c2;
+
+            shared.last_checksum = (c1, c2);
+            (c1, c2)
+        };
+
+        self.max_frame = 0;
+        let shared = self.get_shared();
+        self.io
+            .wait_for_completion(sqlite3_ondisk::begin_write_wal_header(
+                &shared.file,
+                &shared.wal_header.lock(),
+            )?)?;
+        self.io
+            .wait_for_completion(shared.file.sync(Completion::new_sync(|_| {}))?)?;
+        Ok(())
+    }
+
+    fn checkpoint_inner(
+        &mut self,
+        pager: &Pager,
+        write_counter: Rc<RefCell<usize>>,
+        mode: CheckpointMode,
+    ) -> Result<IOResult<CheckpointResult>> {
+        'checkpoint_loop: loop {
+            let state = self.ongoing_checkpoint.state;
+            tracing::debug!(?state);
+            match state {
+                // Acquire the relevant exclusive locks and checkpoint_lock
+                // so no other checkpointer can run. fsync WAL if there are unapplied frames.
+                // Decide the largest frame we are allowed to back‑fill.
+                CheckpointState::Start => {
+                    let (max_frame, nbackfills) = {
+                        let shared = self.get_shared();
+                        let max_frame = shared.max_frame.load(Ordering::SeqCst);
+                        let n_backfills = shared.nbackfills.load(Ordering::SeqCst);
+                        (max_frame, n_backfills)
+                    };
+                    let needs_backfill = max_frame > nbackfills;
+                    if !needs_backfill && matches!(mode, CheckpointMode::Passive) {
+                        // there are no frames to copy over and we don't need to reset
+                        // the log so we can return early success.
+                        return Ok(IOResult::Done(self.prev_checkpoint.clone()));
+                    }
+                    // acquire the appropriate exclusive locks depending on the checkpoint mode
+                    self.acquire_proper_checkpoint_guard(mode)?;
+                    self.ongoing_checkpoint.max_frame = self.determine_max_safe_checkpoint_frame();
+                    self.ongoing_checkpoint.min_frame = nbackfills + 1;
+                    self.ongoing_checkpoint.current_page = 0;
+                    self.ongoing_checkpoint.state = CheckpointState::ReadFrame;
+                    tracing::trace!(
+                        "checkpoint_start(min_frame={}, max_frame={})",
+                        self.ongoing_checkpoint.min_frame,
+                        self.ongoing_checkpoint.max_frame,
+                    );
+                }
+                // Find the next page that has a frame in the safe interval and schedule a read of that frame.
+                CheckpointState::ReadFrame => {
+                    let shared = self.get_shared();
+                    let min_frame = self.ongoing_checkpoint.min_frame;
+                    let max_frame = self.ongoing_checkpoint.max_frame;
+                    let pages_in_frames = shared.pages_in_frames.clone();
+                    let pages_in_frames = pages_in_frames.lock();
+
+                    let frame_cache = shared.frame_cache.clone();
+                    let frame_cache = frame_cache.lock();
+                    assert!(self.ongoing_checkpoint.current_page as usize <= pages_in_frames.len());
+                    if self.ongoing_checkpoint.current_page as usize == pages_in_frames.len() {
+                        self.ongoing_checkpoint.state = CheckpointState::Done;
+                        continue 'checkpoint_loop;
+                    }
+                    let page = pages_in_frames[self.ongoing_checkpoint.current_page as usize];
+                    let frames = frame_cache
+                        .get(&page)
+                        .expect("page must be in frame cache if it's in list");
+
+                    for frame in frames.iter().rev() {
+                        if *frame >= min_frame && *frame <= max_frame {
+                            tracing::debug!(
+                                "checkpoint page(state={:?}, page={}, frame={})",
+                                state,
+                                page,
+                                *frame
+                            );
+                            self.ongoing_checkpoint.page.get().id = page as usize;
+                            let _ = self.read_frame(
+                                *frame,
+                                self.ongoing_checkpoint.page.clone(),
+                                self.buffer_pool.clone(),
+                            )?;
+                            self.ongoing_checkpoint.state = CheckpointState::WaitReadFrame;
+                            continue 'checkpoint_loop;
+                        }
+                    }
+                    self.ongoing_checkpoint.current_page += 1;
+                }
+                CheckpointState::WaitReadFrame => {
+                    if self.ongoing_checkpoint.page.is_locked() {
+                        return Ok(IOResult::IO);
+                    } else {
+                        self.ongoing_checkpoint.state = CheckpointState::WritePage;
+                    }
+                }
+                CheckpointState::WritePage => {
+                    self.ongoing_checkpoint.page.set_dirty();
+                    let _ = begin_write_btree_page(
+                        pager,
+                        &self.ongoing_checkpoint.page,
+                        write_counter.clone(),
+                    )?;
+                    self.ongoing_checkpoint.state = CheckpointState::WaitWritePage;
+                }
+                CheckpointState::WaitWritePage => {
+                    if *write_counter.borrow() > 0 {
+                        return Ok(IOResult::IO);
+                    }
+                    // If page was in cache clear it.
+                    if let Some(page) = pager.cache_get(self.ongoing_checkpoint.page.get().id) {
+                        page.clear_dirty();
+                    }
+                    self.ongoing_checkpoint.page.clear_dirty();
+                    let shared = self.get_shared();
+                    if (self.ongoing_checkpoint.current_page as usize)
+                        < shared.pages_in_frames.lock().len()
+                    {
+                        self.ongoing_checkpoint.current_page += 1;
+                        self.ongoing_checkpoint.state = CheckpointState::ReadFrame;
+                    } else {
+                        self.ongoing_checkpoint.state = CheckpointState::Done;
+                    }
+                }
+                // All eligible frames copied to the db file
+                // Update nBackfills
+                // In Restart or Truncate mode, we need to restart the log over and possibly truncate the file
+                // Release all locks and return the current num of wal frames and the amount we backfilled
+                CheckpointState::Done => {
+                    if *write_counter.borrow() > 0 {
+                        return Ok(IOResult::IO);
+                    }
+                    let mut checkpoint_result = {
+                        let shared = self.get_shared();
+                        let current_mx = shared.max_frame.load(Ordering::SeqCst);
+                        let nbackfills = shared.nbackfills.load(Ordering::SeqCst);
+                        // Record two num pages fields to return as checkpoint result to caller.
+                        // Ref: pnLog, pnCkpt on https://www.sqlite.org/c3ref/wal_checkpoint_v2.html
+
+                        // the total # of frames we could have possibly backfilled
+                        let frames_possible = current_mx.saturating_sub(nbackfills);
+
+                        // the total # of frames we actually backfilled
+                        let frames_checkpointed = self
+                            .ongoing_checkpoint
+                            .max_frame
+                            .saturating_sub(self.ongoing_checkpoint.min_frame - 1);
+
+                        if matches!(mode, CheckpointMode::Truncate) {
+                            // sqlite always returns zeros for truncate mode
+                            CheckpointResult::default()
+                        } else if frames_checkpointed == 0
+                            && matches!(mode, CheckpointMode::Restart)
+                        // if we restarted the log but didn't backfill pages we still have to
+                        // return the last checkpoint result.
+                        {
+                            self.prev_checkpoint.clone()
+                        } else {
+                            // otherwise return the normal result of the total # of possible frames
+                            // we could have backfilled, and the number we actually did.
+                            CheckpointResult::new(frames_possible, frames_checkpointed)
+                        }
+                    };
+
+                    // store the max frame we were able to successfully checkpoint.
+                    self.get_shared()
+                        .nbackfills
+                        .store(self.ongoing_checkpoint.max_frame, Ordering::SeqCst);
+
+                    if matches!(mode, CheckpointMode::Restart | CheckpointMode::Truncate) {
+                        if checkpoint_result.everything_backfilled() {
+                            self.restart_log(mode)?;
+                        } else {
+                            return Err(LimboError::Busy);
+                        }
+                    }
+
+                    // store a copy of the checkpoint result to return in the future if pragma
+                    // wal_checkpoint is called and we haven't backfilled again since.
+                    self.prev_checkpoint = checkpoint_result.clone();
+
+                    // we cannot truncate the db file here because we are currently inside a
+                    // mut borrow of pager.wal, and accessing the header will attempt a borrow
+                    // during 'read_page', so the caller will use the result to determine if:
+                    // a. the max frame == num wal frames (everything backfilled)
+                    // b. the physical db file size differs from the expected pages * page_size
+                    // and truncate + sync the db file if necessary.
+                    if checkpoint_result.everything_backfilled()
+                        && checkpoint_result.num_checkpointed_frames > 0
+                    {
+                        checkpoint_result.maybe_guard = self.checkpoint_guard.take();
+                    } else {
+                        let _ = self.checkpoint_guard.take();
+                    }
+                    self.ongoing_checkpoint.state = CheckpointState::Start;
+                    return Ok(IOResult::Done(checkpoint_result));
+                }
+            }
+        }
+    }
+
+    /// Coordinate what the maximum safe frame is for us to backfill when checkpointing.
+    /// We can never backfill a frame with a higher number than any reader's max frame,
+    /// because we might overwrite content the reader is reading from the database file.
+    ///
+    /// A checkpoint must never overwrite a page in the main DB file if some
+    /// active reader might still need to read that page from the WAL.  
+    /// Concretely: the checkpoint may only copy frames `<= aReadMark[k]` for
+    /// every in‑use reader slot `k > 0`.
+    ///
+    /// `read_locks[0]` is special: readers holding slot 0 ignore the WAL entirely
+    /// (they read only the DB file). Its value is a placeholder and does not
+    /// constrain `mxSafeFrame`.
+    ///
+    /// Slot 1 is the “default” reader slot. If it is free (we can take its
+    /// write-lock) we raise it to the global max so new readers see the most
+    /// recent snapshot. We do not clear it to `READMARK_NOT_USED` in ordinary
+    /// checkpoints (SQLite only clears nonzero slots during a log reset).
+    ///
+    /// Slots 2..N: If a reader is stuck at an older frame, that frame becomes the
+    /// limit. If we can’t atomically bump that slot (write-lock fails), we must
+    /// clamp `mxSafeFrame` down to that mark. In PASSIVE mode we stop trying
+    /// immediately (we are not allowed to block or spin). In the blocking modes
+    /// (FULL/RESTART/TRUNCATE) we can loop and retry, but for now we can
+    /// just respect the first busy slot and move on.
+    ///
+    /// Locking rules:
+    /// This routine tries to take an exclusive (write) lock on each slot to
+    /// update/clean it. If the try-lock fails:
+    /// PASSIVE: do not wait; just lower `mxSafeFrame` and break.
+    /// Others: lower `mxSafeFrame` and continue scanning.
+    ///
+    /// We never modify slot values while a reader holds that slot.
+    fn determine_max_safe_checkpoint_frame(&self) -> u64 {
+        let shared = self.get_shared();
+        let mut max_safe_frame = shared.max_frame.load(Ordering::SeqCst);
+
+        for (read_lock_idx, read_lock) in shared.read_locks.iter_mut().enumerate().skip(1) {
+            let this_mark = read_lock.value.load(Ordering::SeqCst);
+            if this_mark < max_safe_frame as u32 {
+                let busy = !read_lock.write();
+                if !busy {
+                    let val = if read_lock_idx == 1 {
+                        // store the shared max_frame for the default read slot 1
+                        max_safe_frame as u32
+                    } else {
+                        READMARK_NOT_USED
+                    };
+                    read_lock.value.store(val, Ordering::SeqCst);
+                    read_lock.unlock();
+                } else {
+                    max_safe_frame = this_mark as u64;
+                }
+            }
+        }
+        max_safe_frame
+    }
+
+    /// Called once the entire WAL has been back‑filled in RESTART or TRUNCATE mode.
+    /// Must be invoked while writer and checkpoint locks are still held.
+    fn restart_log(&mut self, mode: CheckpointMode) -> Result<()> {
+        turso_assert!(
+            matches!(mode, CheckpointMode::Restart | CheckpointMode::Truncate),
+            "CheckpointMode must be Restart or Truncate"
+        );
+        turso_assert!(
+            matches!(self.checkpoint_guard, Some(CheckpointLocks::Writer { .. })),
+            "We must hold writer and checkpoint locks to restart the log, found: {:?}",
+            self.checkpoint_guard
+        );
+        tracing::info!("restart_log(mode={mode:?})");
+        {
+            // Block all readers
+            let shared = self.get_shared();
+            for idx in 1..shared.read_locks.len() {
+                let lock = &mut shared.read_locks[idx];
+                if !lock.write() {
+                    // release everything we got so far
+                    for j in 1..idx {
+                        shared.read_locks[j].unlock();
+                    }
+                    // Reader is active, cannot proceed
+                    return Err(LimboError::Busy);
+                }
+                // after the log is reset, we must set all secondary marks to READMARK_NOT_USED so the next reader selects a fresh slot
+                lock.value.store(READMARK_NOT_USED, Ordering::SeqCst);
+            }
+        }
+
+        let handle_err = |e: &LimboError| {
+            // release all read locks we just acquired, the caller will take care of the others
+            let shared = self.get_shared();
+            for idx in 1..shared.read_locks.len() {
+                shared.read_locks[idx].unlock();
+            }
+            tracing::error!(
+                "Failed to restart WAL header: {:?}, releasing read locks",
+                e
+            );
+        };
+        // reinitialize in‑memory state
+        self.get_shared()
+            .restart_wal_header(&self.io, mode)
+            .inspect_err(|e| {
+                handle_err(e);
+            })?;
+
+        // For TRUNCATE mode: shrink the WAL file to 0 B
+        if matches!(mode, CheckpointMode::Truncate) {
+            let c = Completion::new_trunc(|_| {
+                tracing::trace!("WAL file truncated to 0 B");
+            });
+            let shared = self.get_shared();
+            // for now at least, lets do all this IO syncronously
+            let c = shared.file.truncate(0, c).inspect_err(handle_err)?;
+            self.io.wait_for_completion(c).inspect_err(handle_err)?;
+            // fsync after truncation
+            self.io
+                .wait_for_completion(
+                    shared
+                        .file
+                        .sync(Completion::new_sync(|_| {
+                            tracing::trace!("WAL file synced after reset/truncation");
+                        }))
+                        .inspect_err(handle_err)?,
+                )
+                .inspect_err(handle_err)?;
+        }
+
+        // release read‑locks 1..4
+        {
+            let shared = self.get_shared();
+            for idx in 1..shared.read_locks.len() {
+                shared.read_locks[idx].unlock();
+            }
+        }
+
+        self.last_checksum = self.get_shared().last_checksum;
+        self.max_frame = 0;
+        self.min_frame = 0;
+        Ok(())
+    }
+
+    fn acquire_proper_checkpoint_guard(&mut self, mode: CheckpointMode) -> Result<()> {
+        let needs_new_guard = !matches!(
+            (&self.checkpoint_guard, mode),
+            (Some(CheckpointLocks::Read0 { .. }), CheckpointMode::Passive,)
+                | (
+                    Some(CheckpointLocks::Writer { .. }),
+                    CheckpointMode::Restart | CheckpointMode::Truncate,
+                ),
+        );
+        if needs_new_guard {
+            // Drop any existing guard
+            if self.checkpoint_guard.is_some() {
+                let _ = self.checkpoint_guard.take();
+            }
+            let guard = CheckpointLocks::new(self.shared.clone(), mode)?;
+            self.checkpoint_guard = Some(guard);
+        }
+        Ok(())
+    }
 }
 
 impl WalFileShared {
@@ -1228,16 +1721,27 @@ impl WalFileShared {
         wal_header.checksum_1 = checksums.0;
         wal_header.checksum_2 = checksums.1;
         let c = sqlite3_ondisk::begin_write_wal_header(&file, &wal_header)?;
-        // TODO: for now wait for completion
-        io.wait_for_completion(c)?;
         let header = Arc::new(SpinLock::new(wal_header));
         let checksum = {
             let checksum = header.lock();
             (checksum.checksum_1, checksum.checksum_2)
         };
+        io.wait_for_completion(c)?;
         tracing::debug!("new_shared(header={:?})", header);
+        let read_locks = array::from_fn(|_| LimboRwLock {
+            lock: AtomicU32::new(NO_LOCK),
+            nreads: AtomicU32::new(0),
+            value: AtomicU32::new(READMARK_NOT_USED),
+        });
+
+        // slot zero is always zero as it signifies that reads can be done from the db file
+        // directly, and slot 1 is the default read mark containing the max frame. in this case
+        // our max frame is zero so both slots 0 and 1 begin at 0
+        read_locks[0].value.store(0, Ordering::SeqCst);
+        read_locks[1].value.store(0, Ordering::SeqCst);
+
         let shared = WalFileShared {
-            wal_header: header,
+            wal_header: Arc::new(SpinLock::new(wal_header)),
             min_frame: AtomicU64::new(0),
             max_frame: AtomicU64::new(0),
             nbackfills: AtomicU64::new(0),
@@ -1245,11 +1749,7 @@ impl WalFileShared {
             last_checksum: checksum,
             file,
             pages_in_frames: Arc::new(SpinLock::new(Vec::new())),
-            read_locks: array::from_fn(|_| LimboRwLock {
-                lock: AtomicU32::new(NO_LOCK),
-                nreads: AtomicU32::new(0),
-                value: AtomicU32::new(READMARK_NOT_USED),
-            }),
+            read_locks,
             write_lock: LimboRwLock {
                 lock: AtomicU32::new(NO_LOCK),
                 nreads: AtomicU32::new(0),
@@ -1264,4 +1764,857 @@ impl WalFileShared {
     pub fn page_size(&self) -> u32 {
         self.wal_header.lock().page_size
     }
+
+    /// Called after a successful RESTART/TRUNCATE mode checkpoint
+    /// when all frames are back‑filled.
+    ///
+    /// sqlite3/src/wal.c
+    /// The following is guaranteed when this function is called:
+    ///
+    ///   a) the WRITER lock is held,
+    ///   b) the entire log file has been checkpointed, and
+    ///   c) any existing readers are reading exclusively from the database
+    ///      file - there are no readers that may attempt to read a frame from
+    ///      the log file.
+    ///
+    /// This function updates the shared-memory structures so that the next
+    /// client to write to the database (which may be this one) does so by
+    /// writing frames into the start of the log file.
+    fn restart_wal_header(&mut self, io: &Arc<dyn IO>, mode: CheckpointMode) -> Result<()> {
+        turso_assert!(
+            matches!(mode, CheckpointMode::Restart | CheckpointMode::Truncate),
+            "CheckpointMode must be Restart or Truncate"
+        );
+        {
+            let mut hdr = self.wal_header.lock();
+            hdr.checkpoint_seq = hdr.checkpoint_seq.wrapping_add(1);
+            // keep hdr.magic, hdr.file_format, hdr.page_size as-is
+            hdr.salt_1 = hdr.salt_1.wrapping_add(1);
+            hdr.salt_2 = io.generate_random_number() as u32;
+
+            self.max_frame.store(0, Ordering::SeqCst);
+            self.nbackfills.store(0, Ordering::SeqCst);
+            self.last_checksum = (hdr.checksum_1, hdr.checksum_2);
+        }
+
+        self.frame_cache.lock().clear();
+        self.pages_in_frames.lock().clear();
+
+        // read-marks
+        self.read_locks[0].value.store(0, Ordering::SeqCst);
+        self.read_locks[1].value.store(0, Ordering::SeqCst);
+        for l in &self.read_locks[2..] {
+            l.value.store(READMARK_NOT_USED, Ordering::SeqCst);
+        }
+        Ok(())
+    }
+}
+
+#[cfg(test)]
+pub mod test {
+    use crate::{
+        result::LimboResult,
+        storage::{
+            sqlite3_ondisk::{self, WAL_HEADER_SIZE},
+            wal::READMARK_NOT_USED,
+        },
+        types::IOResult,
+        CheckpointMode, CheckpointResult, Completion, Connection, Database, LimboError, PlatformIO,
+        StepResult, Wal, WalFile, WalFileShared, IO,
+    };
+    #[cfg(unix)]
+    use std::os::unix::fs::MetadataExt;
+    use std::{
+        cell::{Cell, RefCell, UnsafeCell},
+        rc::Rc,
+        sync::{atomic::Ordering, Arc},
+    };
+    #[allow(clippy::arc_with_non_send_sync)]
+    fn get_database() -> (Arc<Database>, std::path::PathBuf) {
+        let mut path = tempfile::tempdir().unwrap().keep();
+        let dbpath = path.clone();
+        path.push("test.db");
+        {
+            let connection = rusqlite::Connection::open(&path).unwrap();
+            connection
+                .pragma_update(None, "journal_mode", "wal")
+                .unwrap();
+        }
+        let io: Arc<dyn IO> = Arc::new(PlatformIO::new().unwrap());
+        let db = Database::open_file(io.clone(), path.to_str().unwrap(), false, false).unwrap();
+        // db + tmp directory
+        (db, dbpath)
+    }
+    #[test]
+    fn test_truncate_file() {
+        let (db, _path) = get_database();
+        let conn = db.connect().unwrap();
+        conn.execute("create table test (id integer primary key, value text)")
+            .unwrap();
+        let _ = conn.execute("insert into test (value) values ('test1'), ('test2'), ('test3')");
+        let wal = db.maybe_shared_wal.write();
+        let wal_file = wal.as_ref().unwrap();
+        let file = unsafe { &mut *wal_file.get() };
+        let done = Rc::new(Cell::new(false));
+        let _done = done.clone();
+        let _ = file.file.truncate(
+            WAL_HEADER_SIZE,
+            Completion::new_trunc(move |_| {
+                let done = _done.clone();
+                done.set(true);
+            }),
+        );
+        assert!(file.file.size().unwrap() == WAL_HEADER_SIZE as u64);
+        assert!(done.get());
+    }
+
+    #[test]
+    fn test_wal_truncate_checkpoint() {
+        let (db, path) = get_database();
+        let mut walpath = path.clone().into_os_string().into_string().unwrap();
+        walpath.push_str("/test.db-wal");
+        let walpath = std::path::PathBuf::from(walpath);
+
+        let conn = db.connect().unwrap();
+        conn.execute("create table test (id integer primary key, value text)")
+            .unwrap();
+        for _i in 0..25 {
+            let _ = conn.execute("insert into test (value) values (randomblob(1024)), (randomblob(1024)), (randomblob(1024))");
+        }
+        let pager = conn.pager.borrow_mut();
+        let _ = pager.cacheflush();
+        let mut wal = pager.wal.borrow_mut();
+
+        let stat = std::fs::metadata(&walpath).unwrap();
+        let meta_before = std::fs::metadata(&walpath).unwrap();
+        let bytes_before = meta_before.len();
+        run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Truncate);
+        drop(wal);
+
+        assert_eq!(pager.wal_frame_count().unwrap(), 0);
+
+        tracing::info!("wal filepath: {walpath:?}, size: {}", stat.len());
+        let meta_after = std::fs::metadata(&walpath).unwrap();
+        let bytes_after = meta_after.len();
+        assert_ne!(
+            bytes_before, bytes_after,
+            "WAL file should not have been empty before checkpoint"
+        );
+        assert_eq!(
+            bytes_after, 0,
+            "WAL file should be truncated to 0 bytes, but is {bytes_after} bytes",
+        );
+        std::fs::remove_dir_all(path).unwrap();
+    }
+
+    fn bulk_inserts(conn: &Arc<Connection>, n_txns: usize, rows_per_txn: usize) {
+        for _ in 0..n_txns {
+            conn.execute("begin transaction").unwrap();
+            for i in 0..rows_per_txn {
+                conn.execute(format!("insert into test(value) values ('v{i}')"))
+                    .unwrap();
+            }
+            conn.execute("commit").unwrap();
+        }
+    }
+
+    fn run_checkpoint_until_done(
+        wal: &mut dyn Wal,
+        pager: &crate::Pager,
+        mode: CheckpointMode,
+    ) -> CheckpointResult {
+        let wc = Rc::new(RefCell::new(0usize));
+        loop {
+            match wal.checkpoint(pager, wc.clone(), mode).unwrap() {
+                IOResult::Done(r) => return r,
+                IOResult::IO => {
+                    pager.io.run_once().unwrap();
+                }
+            }
+        }
+    }
+
+    fn wal_header_snapshot(shared: &Arc<UnsafeCell<WalFileShared>>) -> (u32, u32, u32, u32) {
+        // (checkpoint_seq, salt1, salt2, page_size)
+        unsafe {
+            let hdr = (*shared.get()).wal_header.lock();
+            (hdr.checkpoint_seq, hdr.salt_1, hdr.salt_2, hdr.page_size)
+        }
+    }
+
+    #[test]
+    fn restart_checkpoint_reset_wal_state_handling() {
+        let (db, path) = get_database();
+
+        let walpath = {
+            let mut p = path.clone().into_os_string().into_string().unwrap();
+            p.push_str("/test.db-wal");
+            std::path::PathBuf::from(p)
+        };
+
+        let conn = db.connect().unwrap();
+        conn.execute("create table test(id integer primary key, value text)")
+            .unwrap();
+        bulk_inserts(&conn, 20, 3);
+        while let IOResult::IO = conn.pager.borrow_mut().cacheflush().unwrap() {
+            conn.run_once().unwrap();
+        }
+
+        // Snapshot header & counters before the RESTART checkpoint.
+        let wal_shared = db.maybe_shared_wal.read().as_ref().unwrap().clone();
+        let (seq_before, salt1_before, salt2_before, _ps_before) = wal_header_snapshot(&wal_shared);
+        let (mx_before, backfill_before) = unsafe {
+            let s = &*wal_shared.get();
+            (
+                s.max_frame.load(Ordering::SeqCst),
+                s.nbackfills.load(Ordering::SeqCst),
+            )
+        };
+        assert!(mx_before > 0);
+        assert_eq!(backfill_before, 0);
+
+        let meta_before = std::fs::metadata(&walpath).unwrap();
+        #[cfg(unix)]
+        let size_before = meta_before.blocks();
+        #[cfg(not(unix))]
+        let size_before = meta_before.len();
+        // Run a RESTART checkpoint, should backfill everything and reset WAL counters,
+        // but NOT truncate the file.
+        {
+            let pager = conn.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            let res = run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Restart);
+            assert_eq!(res.num_wal_frames, mx_before);
+            assert_eq!(res.num_checkpointed_frames, mx_before);
+        }
+
+        // Validate post‑RESTART header & counters.
+        let (seq_after, salt1_after, salt2_after, _ps_after) = wal_header_snapshot(&wal_shared);
+        assert_eq!(
+            seq_after,
+            seq_before.wrapping_add(1),
+            "checkpoint_seq must increment on RESTART"
+        );
+        assert_eq!(
+            salt1_after,
+            salt1_before.wrapping_add(1),
+            "salt_1 is incremented"
+        );
+        assert_ne!(salt2_after, salt2_before, "salt_2 is randomized");
+
+        let (mx_after, backfill_after) = unsafe {
+            let s = &*wal_shared.get();
+            (
+                s.max_frame.load(Ordering::SeqCst),
+                s.nbackfills.load(Ordering::SeqCst),
+            )
+        };
+        assert_eq!(mx_after, 0, "mxFrame reset to 0 after RESTART");
+        assert_eq!(backfill_after, 0, "nBackfill reset to 0 after RESTART");
+
+        // File size should be unchanged for RESTART (no truncate).
+        let meta_after = std::fs::metadata(&walpath).unwrap();
+        #[cfg(unix)]
+        let size_after = meta_after.blocks();
+        #[cfg(not(unix))]
+        let size_after = meta_after.len();
+        assert_eq!(
+            size_before, size_after,
+            "RESTART must not change WAL file size"
+        );
+
+        // Next write should start a new sequence at frame 1.
+        conn.execute("insert into test(value) values ('post_restart')")
+            .unwrap();
+        conn.pager
+            .borrow_mut()
+            .wal
+            .borrow_mut()
+            .finish_append_frames_commit()
+            .unwrap();
+        let new_max = unsafe { (&*wal_shared.get()).max_frame.load(Ordering::SeqCst) };
+        assert_eq!(new_max, 1, "first append after RESTART starts at frame 1");
+
+        std::fs::remove_dir_all(path).unwrap();
+    }
+
+    #[test]
+    fn test_wal_passive_partial_then_complete() {
+        let (db, _tmp) = get_database();
+        let conn1 = db.connect().unwrap();
+        let conn2 = db.connect().unwrap();
+
+        conn1
+            .execute("create table test(id integer primary key, value text)")
+            .unwrap();
+        bulk_inserts(&conn1.clone(), 15, 2);
+        while let IOResult::IO = conn1.pager.borrow_mut().cacheflush().unwrap() {
+            conn1.run_once().unwrap();
+        }
+
+        // Force a read transaction that will freeze a lower read mark
+        let readmark = {
+            let pager = conn2.pager.borrow_mut();
+            let mut wal2 = pager.wal.borrow_mut();
+            assert!(matches!(wal2.begin_read_tx().unwrap().0, LimboResult::Ok));
+            wal2.get_max_frame()
+        };
+
+        // generate more frames that the reader will not see.
+        bulk_inserts(&conn1.clone(), 15, 2);
+        while let IOResult::IO = conn1.pager.borrow_mut().cacheflush().unwrap() {
+            conn1.run_once().unwrap();
+        }
+
+        // Run passive checkpoint, expect partial
+        let (res1, max_before) = {
+            let pager = conn1.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            let res = run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Passive);
+            let maxf = unsafe {
+                (&*db.maybe_shared_wal.read().as_ref().unwrap().get())
+                    .max_frame
+                    .load(Ordering::SeqCst)
+            };
+            (res, maxf)
+        };
+        assert_eq!(res1.num_wal_frames, max_before);
+        assert!(
+            res1.num_checkpointed_frames < res1.num_wal_frames,
+            "Partial backfill expected, {} : {}",
+            res1.num_checkpointed_frames,
+            res1.num_wal_frames
+        );
+        assert_eq!(
+            res1.num_checkpointed_frames, readmark,
+            "Checkpointed frames should match read mark"
+        );
+        // Release reader
+        {
+            let pager = conn2.pager.borrow_mut();
+            let wal2 = pager.wal.borrow_mut();
+            wal2.end_read_tx();
+        }
+
+        // Second passive checkpoint should finish
+        let pager = conn1.pager.borrow();
+        let mut wal = pager.wal.borrow_mut();
+        let res2 = run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Passive);
+        assert_eq!(
+            res2.num_checkpointed_frames, res2.num_wal_frames,
+            "Second checkpoint completes remaining frames"
+        );
+    }
+
+    #[test]
+    fn test_wal_restart_blocks_readers() {
+        let (db, _) = get_database();
+        let conn1 = db.connect().unwrap();
+        let conn2 = db.connect().unwrap();
+
+        // Start a read transaction
+        conn2
+            .pager
+            .borrow_mut()
+            .wal
+            .borrow_mut()
+            .begin_read_tx()
+            .unwrap();
+
+        // checkpoint should succeed here because the wal is fully checkpointed (empty)
+        // so the reader is using readmark0 to read directly from the db file.
+        let p = conn1.pager.borrow();
+        let mut w = p.wal.borrow_mut();
+        loop {
+            match w.checkpoint(&p, Rc::new(RefCell::new(0)), CheckpointMode::Restart) {
+                Ok(IOResult::IO) => {
+                    conn1.run_once().unwrap();
+                }
+                e => {
+                    assert!(
+                        matches!(e, Err(LimboError::Busy)),
+                        "reader is holding readmark0 we should return Busy"
+                    );
+                    break;
+                }
+            }
+        }
+        drop(w);
+        conn2.pager.borrow_mut().end_read_tx().unwrap();
+
+        conn1
+            .execute("create table test(id integer primary key, value text)")
+            .unwrap();
+        for i in 0..10 {
+            conn1
+                .execute(format!("insert into test(value) values ('value{i}')"))
+                .unwrap();
+        }
+        // now that we have some frames to checkpoint, try again
+        conn2.pager.borrow_mut().begin_read_tx().unwrap();
+        let p = conn1.pager.borrow();
+        let mut w = p.wal.borrow_mut();
+        loop {
+            match w.checkpoint(&p, Rc::new(RefCell::new(0)), CheckpointMode::Restart) {
+                Ok(IOResult::IO) => {
+                    conn1.run_once().unwrap();
+                }
+                Ok(IOResult::Done(_)) => {
+                    panic!("Checkpoint should not have succeeded");
+                }
+                Err(e) => {
+                    assert!(
+                        matches!(e, LimboError::Busy),
+                        "should return busy if we have readers"
+                    );
+                    break;
+                }
+            }
+        }
+    }
+
+    #[test]
+    fn test_wal_read_marks_after_restart() {
+        let (db, _path) = get_database();
+        let wal_shared = db.maybe_shared_wal.read().as_ref().unwrap().clone();
+
+        let conn = db.connect().unwrap();
+        conn.execute("create table test(id integer primary key, value text)")
+            .unwrap();
+        bulk_inserts(&conn, 10, 5);
+        // Checkpoint with restart
+        {
+            let pager = conn.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            let result = run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Restart);
+            assert!(result.everything_backfilled());
+        }
+
+        // Verify read marks after restart
+        let read_marks_after: Vec<_> = unsafe {
+            let s = &*wal_shared.get();
+            (0..5)
+                .map(|i| s.read_locks[i].value.load(Ordering::SeqCst))
+                .collect()
+        };
+
+        assert_eq!(read_marks_after[0], 0, "Slot 0 should remain 0");
+        assert_eq!(
+            read_marks_after[1], 0,
+            "Slot 1 (default reader) should be reset to 0"
+        );
+        for (i, item) in read_marks_after.iter().take(5).skip(2).enumerate() {
+            assert_eq!(
+                *item, READMARK_NOT_USED,
+                "Slot {i} should be READMARK_NOT_USED after restart",
+            );
+        }
+    }
+
+    #[test]
+    fn test_wal_concurrent_readers_during_checkpoint() {
+        let (db, _path) = get_database();
+        let conn_writer = db.connect().unwrap();
+
+        conn_writer
+            .execute("create table test(id integer primary key, value text)")
+            .unwrap();
+        bulk_inserts(&conn_writer, 5, 10);
+
+        // Start multiple readers at different points
+        let conn_r1 = db.connect().unwrap();
+        let conn_r2 = db.connect().unwrap();
+
+        // R1 starts reading
+        let r1_max_frame = {
+            let pager = conn_r1.pager.borrow_mut();
+            let mut wal = pager.wal.borrow_mut();
+            assert!(matches!(wal.begin_read_tx().unwrap().0, LimboResult::Ok));
+            wal.get_max_frame()
+        };
+        bulk_inserts(&conn_writer, 5, 10);
+
+        // R2 starts reading, sees more frames than R1
+        let r2_max_frame = {
+            let pager = conn_r2.pager.borrow_mut();
+            let mut wal = pager.wal.borrow_mut();
+            assert!(matches!(wal.begin_read_tx().unwrap().0, LimboResult::Ok));
+            wal.get_max_frame()
+        };
+
+        // try passive checkpoint, should only checkpoint up to R1's position
+        let checkpoint_result = {
+            let pager = conn_writer.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Passive)
+        };
+
+        assert!(
+            checkpoint_result.num_checkpointed_frames < checkpoint_result.num_wal_frames,
+            "Should not checkpoint all frames when readers are active"
+        );
+        assert_eq!(
+            checkpoint_result.num_checkpointed_frames, r1_max_frame,
+            "Should have checkpointed up to R1's max frame"
+        );
+
+        // Verify R2 still sees its frames
+        assert_eq!(
+            conn_r2.pager.borrow().wal.borrow().get_max_frame(),
+            r2_max_frame,
+            "Reader should maintain its snapshot"
+        );
+    }
+
+    #[test]
+    fn test_wal_checkpoint_updates_read_marks() {
+        let (db, _path) = get_database();
+        let wal_shared = db.maybe_shared_wal.read().as_ref().unwrap().clone();
+
+        let conn = db.connect().unwrap();
+        conn.execute("create table test(id integer primary key, value text)")
+            .unwrap();
+        bulk_inserts(&conn, 10, 5);
+
+        // get max frame before checkpoint
+        let max_frame_before = unsafe { (*wal_shared.get()).max_frame.load(Ordering::SeqCst) };
+
+        {
+            let pager = conn.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            let _result = run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Passive);
+        }
+
+        // check that read mark 1 (default reader) was updated to max_frame
+        let read_mark_1 = unsafe {
+            (*wal_shared.get()).read_locks[1]
+                .value
+                .load(Ordering::SeqCst)
+        };
+
+        assert_eq!(
+            read_mark_1 as u64, max_frame_before,
+            "Read mark 1 should be updated to max frame during checkpoint"
+        );
+    }
+
+    #[test]
+    fn test_wal_writer_blocks_restart_checkpoint() {
+        let (db, _path) = get_database();
+        let conn1 = db.connect().unwrap();
+        let conn2 = db.connect().unwrap();
+
+        conn1
+            .execute("create table test(id integer primary key, value text)")
+            .unwrap();
+        bulk_inserts(&conn1, 5, 5);
+
+        // start a write transaction
+        {
+            let pager = conn2.pager.borrow_mut();
+            let mut wal = pager.wal.borrow_mut();
+            let _ = wal.begin_read_tx().unwrap();
+            let res = wal.begin_write_tx().unwrap();
+            assert!(matches!(res, LimboResult::Ok), "result: {res:?}");
+        }
+
+        // should fail because writer lock is held
+        let result = {
+            let pager = conn1.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            wal.checkpoint(&pager, Rc::new(RefCell::new(0)), CheckpointMode::Restart)
+        };
+
+        assert!(
+            matches!(result, Err(LimboError::Busy)),
+            "Restart checkpoint should fail when write lock is held"
+        );
+
+        conn2.pager.borrow().wal.borrow().end_read_tx();
+        // release write lock
+        conn2.pager.borrow().wal.borrow().end_write_tx();
+
+        // now restart should succeed
+        let result = {
+            let pager = conn1.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Restart)
+        };
+
+        assert!(result.everything_backfilled());
+    }
+
+    #[test]
+    #[should_panic(expected = "must have a read transaction to begin a write transaction")]
+    fn test_wal_read_transaction_required_before_write() {
+        let (db, _path) = get_database();
+        let conn = db.connect().unwrap();
+
+        conn.execute("create table test(id integer primary key, value text)")
+            .unwrap();
+
+        // Attempt to start a write transaction without a read transaction
+        let pager = conn.pager.borrow();
+        let mut wal = pager.wal.borrow_mut();
+        let _ = wal.begin_write_tx();
+    }
+
+    fn check_read_lock_slot(conn: &Arc<Connection>, expected_slot: usize) -> bool {
+        let pager = conn.pager.borrow();
+        let wal = pager.wal.borrow();
+        let wal_any = wal.as_any();
+        if let Some(wal_file) = wal_any.downcast_ref::<WalFile>() {
+            return wal_file.max_frame_read_lock_index.get() == expected_slot;
+        }
+        false
+    }
+
+    #[test]
+    fn test_wal_multiple_readers_at_different_frames() {
+        let (db, _path) = get_database();
+        let conn_writer = db.connect().unwrap();
+
+        conn_writer
+            .execute("CREATE TABLE test(id INTEGER PRIMARY KEY, value TEXT)")
+            .unwrap();
+
+        fn start_reader(conn: &Arc<Connection>) -> (u64, crate::Statement) {
+            conn.execute("BEGIN").unwrap();
+            let mut stmt = conn.prepare("SELECT * FROM test").unwrap();
+            stmt.step().unwrap();
+            let frame = conn.pager.borrow().wal.borrow().get_max_frame();
+            (frame, stmt)
+        }
+
+        bulk_inserts(&conn_writer, 3, 5);
+
+        let conn1 = &db.connect().unwrap();
+        let (r1_frame, _stmt) = start_reader(conn1); // reader 1
+
+        bulk_inserts(&conn_writer, 3, 5);
+
+        let conn_r2 = db.connect().unwrap();
+        let (r2_frame, _stmt2) = start_reader(&conn_r2); // reader 2
+
+        bulk_inserts(&conn_writer, 3, 5);
+
+        let conn_r3 = db.connect().unwrap();
+        let (r3_frame, _stmt3) = start_reader(&conn_r3); // reader 3
+
+        assert!(r1_frame < r2_frame && r2_frame < r3_frame);
+
+        // passive checkpoint #1
+        let result1 = {
+            let pager = conn_writer.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Passive)
+        };
+        assert_eq!(result1.num_checkpointed_frames, r1_frame);
+
+        // finish reader‑1
+        conn1.execute("COMMIT").unwrap();
+
+        // passive checkpoint #2
+        let result2 = {
+            let pager = conn_writer.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Passive)
+        };
+        assert_eq!(
+            result1.num_checkpointed_frames + result2.num_checkpointed_frames,
+            r2_frame
+        );
+
+        // verify visible rows
+        let mut stmt = conn_r2.query("SELECT COUNT(*) FROM test").unwrap().unwrap();
+        while !matches!(stmt.step().unwrap(), StepResult::Row) {
+            stmt.run_once().unwrap();
+        }
+        let r2_cnt: i64 = stmt.row().unwrap().get(0).unwrap();
+
+        let mut stmt2 = conn_r3.query("SELECT COUNT(*) FROM test").unwrap().unwrap();
+        while !matches!(stmt2.step().unwrap(), StepResult::Row) {
+            stmt2.run_once().unwrap();
+        }
+        let r3_cnt: i64 = stmt2.row().unwrap().get(0).unwrap();
+        assert_eq!(r2_cnt, 30);
+        assert_eq!(r3_cnt, 45);
+    }
+
+    #[test]
+    fn test_checkpoint_truncate_reset_handling() {
+        let (db, path) = get_database();
+        let conn = db.connect().unwrap();
+
+        let walpath = {
+            let mut p = path.clone().into_os_string().into_string().unwrap();
+            p.push_str("/test.db-wal");
+            std::path::PathBuf::from(p)
+        };
+
+        conn.execute("create table test(id integer primary key, value text)")
+            .unwrap();
+        bulk_inserts(&conn, 10, 10);
+
+        // Get size before checkpoint
+        let size_before = std::fs::metadata(&walpath).unwrap().len();
+        assert!(size_before > 0, "WAL file should have content");
+
+        // Do a TRUNCATE checkpoint
+        {
+            let pager = conn.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Truncate);
+        }
+
+        // Check file size after truncate
+        let size_after = std::fs::metadata(&walpath).unwrap().len();
+        assert_eq!(size_after, 0, "WAL file should be truncated to 0 bytes");
+
+        // Verify we can still write to the database
+        conn.execute("INSERT INTO test VALUES (1001, 'after-truncate')")
+            .unwrap();
+
+        // Check WAL has new content
+        let new_size = std::fs::metadata(&walpath).unwrap().len();
+        assert!(new_size >= 32, "WAL file too small");
+        let hdr = read_wal_header(&walpath);
+        let expected_magic = if cfg!(target_endian = "big") {
+            sqlite3_ondisk::WAL_MAGIC_BE
+        } else {
+            sqlite3_ondisk::WAL_MAGIC_LE
+        };
+        assert!(
+            hdr.magic == expected_magic,
+            "bad WAL magic: {:#X}, expected: {:#X}",
+            hdr.magic,
+            sqlite3_ondisk::WAL_MAGIC_BE
+        );
+        assert_eq!(hdr.file_format, 3007000);
+        assert_eq!(hdr.page_size, 4096, "invalid page size");
+        assert_eq!(hdr.checkpoint_seq, 1, "invalid checkpoint_seq");
+        std::fs::remove_dir_all(path).unwrap();
+    }
+
+    fn read_wal_header(path: &std::path::Path) -> sqlite3_ondisk::WalHeader {
+        use std::{fs::File, io::Read};
+        let mut hdr = [0u8; 32];
+        File::open(path).unwrap().read_exact(&mut hdr).unwrap();
+        let be = |i| u32::from_be_bytes(hdr[i..i + 4].try_into().unwrap());
+        sqlite3_ondisk::WalHeader {
+            magic: be(0x00),
+            file_format: be(0x04),
+            page_size: be(0x08),
+            checkpoint_seq: be(0x0C),
+            salt_1: be(0x10),
+            salt_2: be(0x14),
+            checksum_1: be(0x18),
+            checksum_2: be(0x1C),
+        }
+    }
+
+    #[test]
+    fn test_wal_stale_snapshot_in_write_transaction() {
+        let (db, _path) = get_database();
+        let conn1 = db.connect().unwrap();
+        let conn2 = db.connect().unwrap();
+
+        conn1
+            .execute("create table test(id integer primary key, value text)")
+            .unwrap();
+        // Start a read transaction on conn2
+        {
+            let pager = conn2.pager.borrow_mut();
+            let mut wal = pager.wal.borrow_mut();
+            let (res, _) = wal.begin_read_tx().unwrap();
+            assert!(matches!(res, LimboResult::Ok));
+        }
+        // Make changes using conn1
+        bulk_inserts(&conn1, 5, 5);
+        // Try to start a write transaction on conn2 with a stale snapshot
+        let result = {
+            let pager = conn2.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            wal.begin_write_tx()
+        };
+        // Should get Busy due to stale snapshot
+        assert!(matches!(result.unwrap(), LimboResult::Busy));
+
+        // End read transaction and start a fresh one
+        {
+            let pager = conn2.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            wal.end_read_tx();
+            let (res, _) = wal.begin_read_tx().unwrap();
+            assert!(matches!(res, LimboResult::Ok));
+        }
+        // Now write transaction should work
+        let result = {
+            let pager = conn2.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            wal.begin_write_tx()
+        };
+        assert!(matches!(result.unwrap(), LimboResult::Ok));
+    }
+
+    #[test]
+    fn test_wal_readlock0_optimization_behavior() {
+        let (db, _path) = get_database();
+        let conn1 = db.connect().unwrap();
+        let conn2 = db.connect().unwrap();
+
+        conn1
+            .execute("create table test(id integer primary key, value text)")
+            .unwrap();
+        bulk_inserts(&conn1, 5, 5);
+        // Do a full checkpoint to move all data to DB file
+        {
+            let pager = conn1.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Passive);
+        }
+
+        // Start a read transaction on conn2
+        {
+            let pager = conn2.pager.borrow_mut();
+            let mut wal = pager.wal.borrow_mut();
+            let (res, _) = wal.begin_read_tx().unwrap();
+            assert!(matches!(res, LimboResult::Ok));
+        }
+        // should use slot 0, as everything is backfilled
+        assert!(check_read_lock_slot(&conn2, 0));
+        {
+            let pager = conn1.pager.borrow();
+            let wal = pager.wal.borrow();
+            let frame = wal.find_frame(5);
+            // since we hold readlock0, we should ignore the db file and find_frame should return none
+            assert!(frame.is_ok_and(|f| f.is_none()));
+        }
+        // Try checkpoint, should fail because reader has slot 0
+        {
+            let pager = conn1.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            let result = wal.checkpoint(&pager, Rc::new(RefCell::new(0)), CheckpointMode::Restart);
+
+            assert!(
+                matches!(result, Err(LimboError::Busy)),
+                "RESTART checkpoint should fail when a reader is using slot 0"
+            );
+        }
+        // End the read transaction
+        {
+            let pager = conn2.pager.borrow();
+            let wal = pager.wal.borrow();
+            wal.end_read_tx();
+        }
+        {
+            let pager = conn1.pager.borrow();
+            let mut wal = pager.wal.borrow_mut();
+            let result = run_checkpoint_until_done(&mut *wal, &pager, CheckpointMode::Restart);
+            assert!(
+                result.everything_backfilled(),
+                "RESTART checkpoint should succeed after reader releases slot 0"
+            );
+        }
+    }
 }
diff --git a/core/translate/pragma.rs b/core/translate/pragma.rs
index 5265943ae..4c3c64d58 100644
--- a/core/translate/pragma.rs
+++ b/core/translate/pragma.rs
@@ -344,12 +344,6 @@ fn query_pragma(
                 _ => CheckpointMode::Passive,
             };
 
-            if !matches!(mode, CheckpointMode::Passive) {
-                return Err(LimboError::ParseError(
-                    "only Passive mode supported".to_string(),
-                ));
-            }
-
             program.alloc_registers(2);
             program.emit_insn(Insn::Checkpoint {
                 database: 0,
diff --git a/core/vdbe/execute.rs b/core/vdbe/execute.rs
index 429d7c977..9a6cbe9db 100644
--- a/core/vdbe/execute.rs
+++ b/core/vdbe/execute.rs
@@ -62,7 +62,10 @@ use crate::{
     vector::{vector32, vector64, vector_distance_cos, vector_distance_l2, vector_extract},
 };
 
-use crate::{info, BufferPool, MvCursor, OpenFlags, RefValue, Row, StepResult, TransactionState};
+use crate::{
+    info, turso_assert, BufferPool, MvCursor, OpenFlags, RefValue, Row, StepResult,
+    TransactionState,
+};
 
 use super::{
     insn::{Cookie, RegisterOrLiteral},
@@ -326,17 +329,18 @@ pub fn op_checkpoint(
 ) -> Result<InsnFunctionStepResult> {
     let Insn::Checkpoint {
         database: _,
-        checkpoint_mode: _,
+        checkpoint_mode,
         dest,
     } = insn
     else {
         unreachable!("unexpected Insn {:?}", insn)
     };
-    let result = program.connection.checkpoint();
+    let result = program.connection.checkpoint(*checkpoint_mode);
     match result {
         Ok(CheckpointResult {
             num_wal_frames: num_wal_pages,
             num_checkpointed_frames: num_checkpointed_pages,
+            ..
         }) => {
             // https://sqlite.org/pragma.html#pragma_wal_checkpoint
             // 1st col: 1 (checkpoint SQLITE_BUSY) or 0 (not busy).
@@ -1982,6 +1986,20 @@ pub fn op_transaction(
     } else {
         let current_state = conn.transaction_state.get();
         let (new_transaction_state, updated) = match (current_state, write) {
+            // pending state means that we tried beginning a tx and the method returned IO.
+            // instead of ending the read tx, just update the state to pending.
+            (TransactionState::PendingUpgrade, write) => {
+                turso_assert!(
+                    *write,
+                    "pending upgrade should only be set for write transactions"
+                );
+                (
+                    TransactionState::Write {
+                        schema_did_change: false,
+                    },
+                    true,
+                )
+            }
             (TransactionState::Write { schema_did_change }, true) => {
                 (TransactionState::Write { schema_did_change }, false)
             }
@@ -2003,7 +2021,6 @@ pub fn op_transaction(
             ),
             (TransactionState::None, false) => (TransactionState::Read, true),
         };
-
         if updated && matches!(current_state, TransactionState::None) {
             if let LimboResult::Busy = pager.begin_read_tx()? {
                 return Ok(InsnFunctionStepResult::Busy);
@@ -2015,11 +2032,18 @@ pub fn op_transaction(
                 IOResult::Done(r) => {
                     if let LimboResult::Busy = r {
                         pager.end_read_tx()?;
+                        conn.transaction_state.replace(TransactionState::None);
+                        conn.auto_commit.replace(true);
                         return Ok(InsnFunctionStepResult::Busy);
                     }
                 }
                 IOResult::IO => {
-                    pager.end_read_tx()?;
+                    // set the transaction state to pending so we don't have to
+                    // end the read transaction.
+                    program
+                        .connection
+                        .transaction_state
+                        .replace(TransactionState::PendingUpgrade);
                     return Ok(InsnFunctionStepResult::IO);
                 }
             }
@@ -2062,7 +2086,8 @@ pub fn op_auto_commit(
     if *auto_commit != conn.auto_commit.get() {
         if *rollback {
             // TODO(pere): add rollback I/O logic once we implement rollback journal
-            pager.rollback(schema_did_change, &conn)?;
+            return_if_io!(pager.end_tx(true, schema_did_change, &conn, false));
+            conn.transaction_state.replace(TransactionState::None);
             conn.auto_commit.replace(true);
         } else {
             conn.auto_commit.replace(*auto_commit);
@@ -6101,6 +6126,7 @@ pub fn op_set_cookie(
                     },
                     TransactionState::Read => unreachable!("invalid transaction state for SetCookie: TransactionState::Read, should be write"),
                     TransactionState::None => unreachable!("invalid transaction state for SetCookie: TransactionState::None, should be write"),
+                    TransactionState::PendingUpgrade => unreachable!("invalid transaction state for SetCookie: TransactionState::PendingUpgrade, should be write"),
                 }
             }
             program
@@ -6325,6 +6351,9 @@ pub fn op_open_ephemeral(
         }
         OpOpenEphemeralState::StartingTxn { pager } => {
             tracing::trace!("StartingTxn");
+            pager
+                .begin_read_tx() // we have to begin a read tx before beginning a write
+                .expect("Failed to start read transaction");
             return_if_io!(pager.begin_write_tx());
             state.op_open_ephemeral_state = OpOpenEphemeralState::CreateBtree {
                 pager: pager.clone(),
diff --git a/core/vdbe/mod.rs b/core/vdbe/mod.rs
index 4f15705b5..5d9d1fb67 100644
--- a/core/vdbe/mod.rs
+++ b/core/vdbe/mod.rs
@@ -27,7 +27,7 @@ pub mod sorter;
 use crate::{
     error::LimboError,
     function::{AggFunc, FuncCtx},
-    storage::{pager, sqlite3_ondisk::SmallVec},
+    storage::sqlite3_ondisk::SmallVec,
     translate::plan::TableReferences,
     types::{IOResult, RawSlice, TextRef},
     vdbe::execute::{OpIdxInsertState, OpInsertState, OpNewRowidState, OpSeekState},
@@ -398,7 +398,10 @@ impl Program {
                 // Connection is closed for whatever reason, rollback the transaction.
                 let state = self.connection.transaction_state.get();
                 if let TransactionState::Write { schema_did_change } = state {
-                    pager.rollback(schema_did_change, &self.connection)?
+                    match pager.end_tx(true, schema_did_change, &self.connection, false)? {
+                        IOResult::IO => return Ok(StepResult::IO),
+                        IOResult::Done(_) => {}
+                    }
                 }
                 return Err(LimboError::InternalError("Connection closed".to_string()));
             }
@@ -481,6 +484,9 @@ impl Program {
                         Ok(StepResult::Done)
                     }
                     TransactionState::None => Ok(StepResult::Done),
+                    TransactionState::PendingUpgrade => {
+                        panic!("Unexpected transaction state: {current_state:?} during auto-commit",)
+                    }
                 }
             } else {
                 if self.change_cnt_on {
@@ -507,13 +513,10 @@ impl Program {
             connection.wal_checkpoint_disabled.get(),
         )?;
         match cacheflush_status {
-            IOResult::Done(status) => {
+            IOResult::Done(_) => {
                 if self.change_cnt_on {
                     self.connection.set_changes(self.n_change.get());
                 }
-                if matches!(status, pager::PagerCommitResult::Rollback) {
-                    pager.rollback(schema_did_change, connection)?;
-                }
                 connection.transaction_state.replace(TransactionState::None);
                 *commit_state = CommitState::Ready;
             }
@@ -758,11 +761,15 @@ pub fn handle_program_error(
         _ => {
             let state = connection.transaction_state.get();
             if let TransactionState::Write { schema_did_change } = state {
-                if let Err(e) = pager.rollback(schema_did_change, connection) {
-                    tracing::error!("rollback failed: {e}");
-                }
-                if let Err(e) = pager.end_tx(false, schema_did_change, connection, false) {
-                    tracing::error!("end_tx failed: {e}");
+                loop {
+                    match pager.end_tx(true, schema_did_change, connection, false) {
+                        Ok(IOResult::IO) => connection.run_once()?,
+                        Ok(IOResult::Done(_)) => break,
+                        Err(e) => {
+                            tracing::error!("end_tx failed: {e}");
+                            break;
+                        }
+                    }
                 }
             } else if let Err(e) = pager.end_read_tx() {
                 tracing::error!("end_read_tx failed: {e}");
diff --git a/extensions/core/src/vfs_modules.rs b/extensions/core/src/vfs_modules.rs
index f07d2eb81..1a5e48b25 100644
--- a/extensions/core/src/vfs_modules.rs
+++ b/extensions/core/src/vfs_modules.rs
@@ -41,6 +41,7 @@ pub trait VfsFile: Send + Sync {
     fn read(&mut self, buf: &mut [u8], count: usize, offset: i64) -> ExtResult<i32>;
     fn write(&mut self, buf: &[u8], count: usize, offset: i64) -> ExtResult<i32>;
     fn sync(&self) -> ExtResult<()>;
+    fn truncate(&self, len: i64) -> ExtResult<()>;
     fn size(&self) -> i64;
 }
 
@@ -59,6 +60,7 @@ pub struct VfsImpl {
     pub run_once: VfsRunOnce,
     pub current_time: VfsGetCurrentTime,
     pub gen_random_number: VfsGenerateRandomNumber,
+    pub truncate: VfsTruncate,
 }
 
 pub type RegisterVfsFn =
@@ -81,6 +83,8 @@ pub type VfsWrite =
 
 pub type VfsSync = unsafe extern "C" fn(file: *const c_void) -> i32;
 
+pub type VfsTruncate = unsafe extern "C" fn(file: *const c_void, len: i64) -> ResultCode;
+
 pub type VfsLock = unsafe extern "C" fn(file: *const c_void, exclusive: bool) -> ResultCode;
 
 pub type VfsUnlock = unsafe extern "C" fn(file: *const c_void) -> ResultCode;
diff --git a/extensions/tests/src/lib.rs b/extensions/tests/src/lib.rs
index e235c2f46..88ff9f26a 100644
--- a/extensions/tests/src/lib.rs
+++ b/extensions/tests/src/lib.rs
@@ -314,6 +314,11 @@ impl VfsFile for TestFile {
         self.file.sync_all().map_err(|_| ResultCode::Error)
     }
 
+    fn truncate(&self, len: i64) -> ExtResult<()> {
+        log::debug!("truncating file with testing VFS to length: {len}");
+        self.file.set_len(len as u64).map_err(|_| ResultCode::Error)
+    }
+
     fn size(&self) -> i64 {
         self.file.metadata().map(|m| m.len() as i64).unwrap_or(-1)
     }
diff --git a/macros/src/ext/vfs_derive.rs b/macros/src/ext/vfs_derive.rs
index 0ab9d52fc..5e813410a 100644
--- a/macros/src/ext/vfs_derive.rs
+++ b/macros/src/ext/vfs_derive.rs
@@ -11,6 +11,7 @@ pub fn derive_vfs_module(input: TokenStream) -> TokenStream {
     let close_fn_name = format_ident!("{}_close", struct_name);
     let read_fn_name = format_ident!("{}_read", struct_name);
     let write_fn_name = format_ident!("{}_write", struct_name);
+    let trunc_fn_name = format_ident!("{}_truncate", struct_name);
     let lock_fn_name = format_ident!("{}_lock", struct_name);
     let unlock_fn_name = format_ident!("{}_unlock", struct_name);
     let sync_fn_name = format_ident!("{}_sync", struct_name);
@@ -36,6 +37,7 @@ pub fn derive_vfs_module(input: TokenStream) -> TokenStream {
                 unlock: #unlock_fn_name,
                 sync: #sync_fn_name,
                 size: #size_fn_name,
+                truncate: #trunc_fn_name,
                 run_once: #run_once_fn_name,
                 gen_random_number: #generate_random_number_fn_name,
                 current_time: #get_current_time_fn_name,
@@ -59,6 +61,7 @@ pub fn derive_vfs_module(input: TokenStream) -> TokenStream {
                 unlock: #unlock_fn_name,
                 sync: #sync_fn_name,
                 size: #size_fn_name,
+                truncate: #trunc_fn_name,
                 run_once: #run_once_fn_name,
                 gen_random_number: #generate_random_number_fn_name,
                 current_time: #get_current_time_fn_name,
@@ -188,6 +191,20 @@ pub fn derive_vfs_module(input: TokenStream) -> TokenStream {
             0
         }
 
+        #[no_mangle]
+        pub unsafe extern "C" fn #trunc_fn_name(file_ptr: *const ::std::ffi::c_void, len: i64) -> ::turso_ext::ResultCode {
+            if file_ptr.is_null() {
+                return ::turso_ext::ResultCode::Error;
+            }
+            let vfs_file: &mut ::turso_ext::VfsFileImpl = &mut *(file_ptr as *mut ::turso_ext::VfsFileImpl);
+            let file: &mut <#struct_name as ::turso_ext::VfsExtension>::File =
+                &mut *(vfs_file.file as *mut <#struct_name as ::turso_ext::VfsExtension>::File);
+            if <#struct_name as ::turso_ext::VfsExtension>::File::truncate(file, len).is_err() {
+                return ::turso_ext::ResultCode::Error;
+            }
+            ::turso_ext::ResultCode::OK
+        }
+
         #[no_mangle]
         pub unsafe extern "C" fn #size_fn_name(file_ptr: *const ::std::ffi::c_void) -> i64 {
             if file_ptr.is_null() {
diff --git a/simulator/runner/file.rs b/simulator/runner/file.rs
index 1be2cb48b..ba3680333 100644
--- a/simulator/runner/file.rs
+++ b/simulator/runner/file.rs
@@ -225,6 +225,25 @@ impl File for SimulatorFile {
     fn size(&self) -> Result<u64> {
         self.inner.size()
     }
+
+    fn truncate(&self, len: usize, c: turso_core::Completion) -> Result<turso_core::Completion> {
+        if self.fault.get() {
+            return Err(turso_core::LimboError::InternalError(
+                FAULT_ERROR_MSG.into(),
+            ));
+        }
+        let c = if let Some(latency) = self.generate_latency_duration() {
+            let cloned_c = c.clone();
+            let op = Box::new(move |file: &SimulatorFile| file.inner.truncate(len, cloned_c));
+            self.queued_io
+                .borrow_mut()
+                .push(DelayedIo { time: latency, op });
+            c
+        } else {
+            self.inner.truncate(len, c)?
+        };
+        Ok(c)
+    }
 }
 
 impl Drop for SimulatorFile {
diff --git a/sqlite3/src/lib.rs b/sqlite3/src/lib.rs
index d9e562554..2fa5419b6 100644
--- a/sqlite3/src/lib.rs
+++ b/sqlite3/src/lib.rs
@@ -3,7 +3,7 @@
 
 use std::ffi::{self, CStr, CString};
 use tracing::trace;
-use turso_core::{LimboError, Value};
+use turso_core::{CheckpointMode, LimboError, Value};
 
 use std::sync::{Arc, Mutex};
 
@@ -1108,20 +1108,41 @@ pub unsafe extern "C" fn sqlite3_wal_checkpoint(
 pub unsafe extern "C" fn sqlite3_wal_checkpoint_v2(
     db: *mut sqlite3,
     _db_name: *const ffi::c_char,
-    _mode: ffi::c_int,
-    _log_size: *mut ffi::c_int,
-    _checkpoint_count: *mut ffi::c_int,
+    mode: ffi::c_int,
+    log_size: *mut ffi::c_int,
+    checkpoint_count: *mut ffi::c_int,
 ) -> ffi::c_int {
     if db.is_null() {
         return SQLITE_MISUSE;
     }
     let db: &mut sqlite3 = &mut *db;
     let db = db.inner.lock().unwrap();
-    // TODO: Checkpointing modes and reporting back log size and checkpoint count to caller.
-    if db.conn.checkpoint().is_err() {
-        return SQLITE_ERROR;
+    let chkptmode = match mode {
+        SQLITE_CHECKPOINT_PASSIVE => CheckpointMode::Passive,
+        SQLITE_CHECKPOINT_RESTART => CheckpointMode::Restart,
+        SQLITE_CHECKPOINT_TRUNCATE => CheckpointMode::Truncate,
+        SQLITE_CHECKPOINT_FULL => CheckpointMode::Full,
+        _ => return SQLITE_MISUSE, // Unsupported mode
+    };
+    match db.conn.checkpoint(chkptmode) {
+        Ok(res) => {
+            if !log_size.is_null() {
+                (*log_size) = res.num_wal_frames as ffi::c_int;
+            }
+            if !checkpoint_count.is_null() {
+                (*checkpoint_count) = res.num_checkpointed_frames as ffi::c_int;
+            }
+            SQLITE_OK
+        }
+        Err(e) => {
+            println!("Checkpoint error: {e}");
+            if matches!(e, turso_core::LimboError::Busy) {
+                SQLITE_BUSY
+            } else {
+                SQLITE_ERROR
+            }
+        }
     }
-    SQLITE_OK
 }
 
 /// Get the number of frames in the WAL.
diff --git a/sqlite3/tests/compat/mod.rs b/sqlite3/tests/compat/mod.rs
index 9b1b1b56d..700fa6910 100644
--- a/sqlite3/tests/compat/mod.rs
+++ b/sqlite3/tests/compat/mod.rs
@@ -167,16 +167,17 @@ mod tests {
                 SQLITE_OK
             );
 
-            assert_eq!(
-                sqlite3_wal_checkpoint_v2(
-                    db,
-                    ptr::null(),
-                    SQLITE_CHECKPOINT_FULL,
-                    &mut log_size,
-                    &mut checkpoint_count
-                ),
-                SQLITE_OK
-            );
+            // TODO: uncomment when SQLITE_CHECKPOINT_FULL is supported
+            // assert_eq!(
+            //     sqlite3_wal_checkpoint_v2(
+            //         db,
+            //         ptr::null(),
+            //         SQLITE_CHECKPOINT_FULL,
+            //         &mut log_size,
+            //         &mut checkpoint_count
+            //     ),
+            //     SQLITE_OK
+            // );
 
             assert_eq!(
                 sqlite3_wal_checkpoint_v2(
diff --git a/tests/integration/functions/test_wal_api.rs b/tests/integration/functions/test_wal_api.rs
index 9b7b710a3..614eb795b 100644
--- a/tests/integration/functions/test_wal_api.rs
+++ b/tests/integration/functions/test_wal_api.rs
@@ -175,6 +175,7 @@ fn test_wal_frame_transfer_no_schema_changes_rollback() {
     assert_eq!(conn1.wal_frame_count().unwrap(), 14);
     let mut frame = [0u8; 24 + 4096];
     conn2.wal_insert_begin().unwrap();
+    // Intentionally leave out the final commit frame, so the big randomblob is not committed and should not be visible to transactions.
     for frame_id in 1..=(conn1.wal_frame_count().unwrap() as u32 - 1) {
         conn1.wal_get_frame(frame_id, &mut frame).unwrap();
         conn2.wal_insert_frame(frame_id, &frame).unwrap();
diff --git a/tests/integration/query_processing/test_write_path.rs b/tests/integration/query_processing/test_write_path.rs
index df6042452..fc1ff8976 100644
--- a/tests/integration/query_processing/test_write_path.rs
+++ b/tests/integration/query_processing/test_write_path.rs
@@ -3,7 +3,9 @@ use crate::common::{compare_string, do_flush, TempDatabase};
 use log::debug;
 use std::io::{Read, Seek, Write};
 use std::sync::Arc;
-use turso_core::{Connection, Database, LimboError, Row, Statement, StepResult, Value};
+use turso_core::{
+    CheckpointMode, Connection, Database, LimboError, Row, Statement, StepResult, Value,
+};
 
 const WAL_HEADER_SIZE: usize = 32;
 const WAL_FRAME_HEADER_SIZE: usize = 24;
@@ -285,7 +287,7 @@ fn test_wal_checkpoint() -> anyhow::Result<()> {
     for i in 0..iterations {
         let insert_query = format!("INSERT INTO test VALUES ({i})");
         do_flush(&conn, &tmp_db)?;
-        conn.checkpoint()?;
+        conn.checkpoint(CheckpointMode::Passive)?;
         run_query(&tmp_db, &conn, &insert_query)?;
     }