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core/mvcc: few suggestions from pr

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This commit is contained in:
Pere Diaz Bou
2025-11-19 16:44:24 +01:00
parent ca30756dfd
commit b4c11705f3
2 changed files with 38 additions and 24 deletions
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35
core/mvcc/cursor.rs
View File

@@ -3,6 +3,7 @@ use parking_lot::RwLock;
use crate::mvcc::clock::LogicalClock;
use crate::mvcc::database::{MVTableId, MvStore, Row, RowID, RowVersionState};
use crate::storage::btree::{BTreeCursor, BTreeKey, CursorTrait};
use crate::translate::plan::IterationDirection;
use crate::types::{IOResult, ImmutableRecord, RecordCursor, SeekKey, SeekOp, SeekResult};
use crate::{return_if_io, Result};
use crate::{Pager, Value};
@@ -182,14 +183,14 @@ impl<Clock: LogicalClock + 'static> MvccLazyCursor<Clock> {
&mut self,
new_position_in_mvcc: &Option<i64>,
current_rowid_in_btree: &Option<i64>,
forwards: bool,
direction: IterationDirection,
) -> CursorPosition {
tracing::trace!("get_new_position_from_mvcc_and_btree(new_position_in_mvcc={:?}, current_rowid_in_btree={:?}, forwards={})", new_position_in_mvcc, current_rowid_in_btree, forwards);
tracing::trace!("get_new_position_from_mvcc_and_btree(new_position_in_mvcc={:?}, current_rowid_in_btree={:?}, direction={:?})", new_position_in_mvcc, current_rowid_in_btree, direction);
match (new_position_in_mvcc, current_rowid_in_btree) {
(Some(mvcc_rowid), Some(btree_rowid)) => {
// When forwards: choose smaller rowid (mvcc if mvcc < btree, else btree)
// When backwards: choose larger rowid (mvcc if mvcc > btree, else btree)
let use_mvcc = if forwards {
let use_mvcc = if direction == IterationDirection::Forwards {
mvcc_rowid < btree_rowid
} else {
mvcc_rowid > btree_rowid
@@ -263,8 +264,11 @@ impl<Clock: LogicalClock + 'static> CursorTrait for MvccLazyCursor<Clock> {
} else {
None
};
let new_position =
self.get_new_position_from_mvcc_and_btree(&position_in_mvcc, &position_in_btree, false);
let new_position = self.get_new_position_from_mvcc_and_btree(
&position_in_mvcc,
&position_in_btree,
IterationDirection::Backwards,
);
self.current_pos.replace(new_position);
self.invalidate_record();
Ok(IOResult::Done(()))
@@ -381,7 +385,7 @@ impl<Clock: LogicalClock + 'static> CursorTrait for MvccLazyCursor<Clock> {
let new_position = self.get_new_position_from_mvcc_and_btree(
&new_position_in_mvcc,
&current_rowid_in_btree,
true,
IterationDirection::Forwards,
);
self.current_pos.replace(new_position);
self.invalidate_record();
@@ -397,7 +401,6 @@ impl<Clock: LogicalClock + 'static> CursorTrait for MvccLazyCursor<Clock> {
fn prev(&mut self) -> Result<IOResult<bool>> {
let current_state = *self.state.borrow();
if current_state.is_none() {
let end = matches!(self.get_current_pos(), CursorPosition::End);
let max_id = match *self.current_pos.borrow() {
CursorPosition::Loaded {
row_id,
@@ -464,8 +467,7 @@ impl<Clock: LogicalClock + 'static> CursorTrait for MvccLazyCursor<Clock> {
false
};
// get current rowid in mvcc and in btree
// compare both and set loaded to position of the one that is lesser
let new_position_in_mvcc = match new_position_in_mvcc {
let maybe_rowid_mvcc = match new_position_in_mvcc {
CursorPosition::Loaded {
row_id,
in_btree: _,
@@ -474,9 +476,9 @@ impl<Clock: LogicalClock + 'static> CursorTrait for MvccLazyCursor<Clock> {
CursorPosition::BeforeFirst => None,
CursorPosition::End => None,
};
let current_rowid_in_btree = if found {
let maybe_rowid_in_btree = if found {
let IOResult::Done(Some(rowid)) = self.btree_cursor.rowid()? else {
panic!("BTree should have returned rowid after next");
panic!("BTree should have returned rowid after prev because we found a valid rowid after calling btree_cursor.prev()");
};
if self.query_btree_version_is_valid(rowid) {
Some(rowid)
@@ -493,10 +495,11 @@ impl<Clock: LogicalClock + 'static> CursorTrait for MvccLazyCursor<Clock> {
} else {
None
};
// Update based on direction.
let new_position = self.get_new_position_from_mvcc_and_btree(
&new_position_in_mvcc,
&current_rowid_in_btree,
false,
&maybe_rowid_mvcc,
&maybe_rowid_in_btree,
IterationDirection::Backwards,
);
self.current_pos.replace(new_position);
self.invalidate_record();
@@ -705,14 +708,14 @@ impl<Clock: LogicalClock + 'static> CursorTrait for MvccLazyCursor<Clock> {
.map(|id| id.row_id);
let IOResult::Done(maybe_rowid_in_btree) = self.btree_cursor.rowid()? else {
panic!("BTree should have returned rowid after next");
panic!("BTree should have returned rowid after rewind because we called btree_cursor.rewind()");
};
let maybe_rowid_in_btree =
maybe_rowid_in_btree.filter(|rowid| self.query_btree_version_is_valid(*rowid));
let new_position = self.get_new_position_from_mvcc_and_btree(
&new_position_in_mvcc,
&maybe_rowid_in_btree,
true,
IterationDirection::Forwards,
);
self.current_pos.replace(new_position);
Ok(IOResult::Done(()))

27
core/mvcc/database/mod.rs
View File

@@ -9,6 +9,7 @@ use crate::storage::btree::CursorTrait;
use crate::storage::btree::CursorValidState;
use crate::storage::sqlite3_ondisk::DatabaseHeader;
use crate::storage::wal::TursoRwLock;
use crate::translate::plan::IterationDirection;
use crate::turso_assert;
use crate::types::IOCompletions;
use crate::types::IOResult;
@@ -1267,7 +1268,12 @@ impl<Clock: LogicalClock> MvStore<Clock> {
start: i64,
tx_id: TxID,
) -> Option<RowID> {
let res = self.get_row_id_for_table_in_direction(table_id, start, tx_id, true);
let res = self.get_row_id_for_table_in_direction(
table_id,
start,
tx_id,
IterationDirection::Forwards,
);
tracing::trace!(
"get_next_row_id_for_table(table_id={}, start={}, tx_id={}, res={:?})",
table_id,
@@ -1284,7 +1290,12 @@ impl<Clock: LogicalClock> MvStore<Clock> {
start: i64,
tx_id: TxID,
) -> Option<RowID> {
let res = self.get_row_id_for_table_in_direction(table_id, start, tx_id, false);
let res = self.get_row_id_for_table_in_direction(
table_id,
start,
tx_id,
IterationDirection::Backwards,
);
tracing::trace!(
"get_prev_row_id_for_table(table_id={}, start={}, tx_id={}, res={:?})",
table_id,
@@ -1300,18 +1311,18 @@ impl<Clock: LogicalClock> MvStore<Clock> {
table_id: MVTableId,
start: i64,
tx_id: TxID,
forwards: bool,
direction: IterationDirection,
) -> Option<RowID> {
tracing::trace!(
"getting_row_id_for_table_in_direction(table_id={}, range_start={}, forwards={})",
"getting_row_id_for_table_in_direction(table_id={}, range_start={}, direction={:?})",
table_id,
start,
forwards
direction
);
let tx = self.txs.get(&tx_id).unwrap();
let tx = tx.value();
if forwards {
if direction == IterationDirection::Forwards {
let min_bound = RowID {
table_id,
row_id: start,
@@ -1348,8 +1359,8 @@ impl<Clock: LogicalClock> MvStore<Clock> {
// In backward's direction we iterate in reverse order.
let mut rows = self.rows.range(min_bound..max_bound).rev();
loop {
// We are moving forward, so if a row was deleted we just need to skip it. Therefore, we need
// to loop either until we find a row that is not deleted or until we reach the end of the table.
// We are moving backwards, so if a row was deleted we just need to skip it. Therefore, we need
// to loop either until we find a row that is not deleted or until we reach the beginning of the table.
let next_row = rows.next();
let row = next_row?;