From 2314e7f906662ca2f633c122381851bba7d57b62 Mon Sep 17 00:00:00 2001
From: Diego Reis <reisdiego144@gmail.com>
Date: Mon, 17 Mar 2025 09:50:22 -0300
Subject: [PATCH 1/3] Improve explain output for `Transaction` bytecode.

It isn't SQLite compliant but it helps a lot, specially when the user doesn't know what each register means.
---
 core/vdbe/explain.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/core/vdbe/explain.rs b/core/vdbe/explain.rs
index 0917729c8..613cd66ea 100644
--- a/core/vdbe/explain.rs
+++ b/core/vdbe/explain.rs
@@ -599,7 +599,7 @@ pub fn insn_to_str(
                 0,
                 OwnedValue::build_text(""),
                 0,
-                "".to_string(),
+                format!("write={}", write),
             ),
             Insn::Goto { target_pc } => (
                 "Goto",

From 250478fedfdd925efa58edb4c603e1935ab324d3 Mon Sep 17 00:00:00 2001
From: Diego Reis <reisdiego144@gmail.com>
Date: Mon, 17 Mar 2025 10:01:00 -0300
Subject: [PATCH 2/3] Implement deferred transactions

As explained in docs: https://sqlite.org/lang_transaction.html

"BEGIN DEFERRED statement merely sets a flag on the database connection that turns off the automatic commit that would normally occur when the last statement finishes."

The transaction upgrade (read -> write) is already handled by the VDBE
---
 core/translate/transaction.rs | 7 +++++--
 testing/transactions.test     | 4 ++++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/core/translate/transaction.rs b/core/translate/transaction.rs
index 01994dfd4..60e00e73b 100644
--- a/core/translate/transaction.rs
+++ b/core/translate/transaction.rs
@@ -1,6 +1,6 @@
 use crate::translate::{ProgramBuilder, ProgramBuilderOpts};
 use crate::vdbe::insn::Insn;
-use crate::{bail_parse_error, QueryMode, Result};
+use crate::{QueryMode, Result};
 use limbo_sqlite3_parser::ast::{Name, TransactionType};
 
 pub fn translate_tx_begin(
@@ -18,7 +18,10 @@ pub fn translate_tx_begin(
     let tx_type = tx_type.unwrap_or(TransactionType::Deferred);
     match tx_type {
         TransactionType::Deferred => {
-            bail_parse_error!("BEGIN DEFERRED not supported yet");
+            program.emit_insn(Insn::AutoCommit {
+                auto_commit: false,
+                rollback: false,
+            });
         }
         TransactionType::Immediate | TransactionType::Exclusive => {
             program.emit_insn(Insn::Transaction { write: true });
diff --git a/testing/transactions.test b/testing/transactions.test
index 3a14d8128..142c721f7 100755
--- a/testing/transactions.test
+++ b/testing/transactions.test
@@ -10,3 +10,7 @@ do_execsql_test basic-tx-1 {
 do_execsql_test basic-tx-2 {
   BEGIN EXCLUSIVE; END
 } {}
+
+do_execsql_test basic-tx-3 {
+  BEGIN DEFERRED; END
+  } {}
\ No newline at end of file

From 16396c57c7db6082723d432399cc99e9dc721347 Mon Sep 17 00:00:00 2001
From: Diego Reis <reisdiego144@gmail.com>
Date: Mon, 17 Mar 2025 10:06:14 -0300
Subject: [PATCH 3/3] Removes unnecessary clone

---
 core/vdbe/mod.rs | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/core/vdbe/mod.rs b/core/vdbe/mod.rs
index af3349a55..95e115ad9 100644
--- a/core/vdbe/mod.rs
+++ b/core/vdbe/mod.rs
@@ -1263,9 +1263,7 @@ impl Program {
                             }
                         }
                         if updated {
-                            connection
-                                .transaction_state
-                                .replace(new_transaction_state.clone());
+                            connection.transaction_state.replace(new_transaction_state);
                         }
                     }
                     state.pc += 1;