aljaz/turso
1
0
Fork 0
mirror of https://github.com/aljazceru/turso.git synced 2026-02-23 08:55:40 +01:00
Code Issues Packages Projects Releases Wiki Activity

make cursor seek reentrant

Browse Source
This commit is contained in:
pedrocarlo
2025-05-30 13:25:46 -03:00
parent 09e6bb5438
commit 33480540f1
2 changed files with 149 additions and 40 deletions
Download Patch File Download Diff File Expand all files Collapse all files

188
core/storage/btree.rs
View File

@@ -395,6 +395,84 @@ enum CursorValidState {
RequireSeek,
}
#[derive(Debug)]
/// State used for seeking
enum CursorSeekState {
Start,
Seeking {
/// Min cell_idx
min: isize,
/// Max cell_idx
max: isize,
nearest_matching_cell: Option<usize>,
},
}
// These functions below exist to avoid problems with the borrow checker
impl CursorSeekState {
/// # Safety
/// method can only be called on CursorSeekState::Seeking
fn set_nearest_matching_cell(&mut self, matching_cell: Option<usize>) {
let CursorSeekState::Seeking {
nearest_matching_cell,
..
} = self
else {
unreachable!("method can only be called on CursorSeekState::Seeking")
};
*nearest_matching_cell = matching_cell;
}
/// # Safety
/// method can only be called on CursorSeekState::Seeking
fn get_nearest_matching_cell(&mut self) -> Option<usize> {
let CursorSeekState::Seeking {
nearest_matching_cell,
..
} = self
else {
unreachable!("method can only be called on CursorSeekState::Seeking")
};
nearest_matching_cell.clone()
}
/// # Safety
/// method can only be called on CursorSeekState::Seeking
fn set_max(&mut self, max: isize) {
let CursorSeekState::Seeking { max: max_state, .. } = self else {
unreachable!("method can only be called on CursorSeekState::Seeking")
};
*max_state = max;
}
/// # Safety
/// method can only be called on CursorSeekState::Seeking
fn get_max(&mut self) -> isize {
let CursorSeekState::Seeking { max, .. } = self else {
unreachable!("method can only be called on CursorSeekState::Seeking")
};
*max
}
/// # Safety
/// method can only be called on CursorSeekState::Seeking
fn set_min(&mut self, min: isize) {
let CursorSeekState::Seeking { min: min_state, .. } = self else {
unreachable!("method can only be called on CursorSeekState::Seeking")
};
*min_state = min;
}
/// # Safety
/// method can only be called on CursorSeekState::Seeking
fn get_min(&mut self) -> isize {
let CursorSeekState::Seeking { min, .. } = self else {
unreachable!("method can only be called on CursorSeekState::Seeking")
};
*min
}
}
pub struct BTreeCursor {
/// The multi-version cursor that is used to read and write to the database file.
mv_cursor: Option<Rc<RefCell<MvCursor>>>,
@@ -430,6 +508,7 @@ pub struct BTreeCursor {
/// Contains the Collation Seq for the whole Index
/// This Vec should be empty for Table Btree
collations: Vec<CollationSeq>,
seek_state: CursorSeekState,
}
impl BTreeCursor {
@@ -459,6 +538,7 @@ impl BTreeCursor {
context: None,
valid_state: CursorValidState::Valid,
collations,
seek_state: CursorSeekState::Start,
}
}
@@ -1722,16 +1802,28 @@ impl BTreeCursor {
);
let iter_dir = seek_op.iteration_direction();
let cell_count = contents.cell_count();
let mut min: isize = 0;
let mut max: isize = cell_count as isize - 1;
if matches!(self.seek_state, CursorSeekState::Start) {
let cell_count = contents.cell_count();
let min: isize = 0;
let max: isize = cell_count as isize - 1;
// If iter dir is forwards, we want the first cell that matches;
// If iter dir is backwards, we want the last cell that matches.
let nearest_matching_cell = None;
self.seek_state = CursorSeekState::Seeking {
min,
max,
nearest_matching_cell,
};
}
// If iter dir is forwards, we want the first cell that matches;
// If iter dir is backwards, we want the last cell that matches.
let mut nearest_matching_cell = None;
loop {
let min = self.seek_state.get_min();
let max = self.seek_state.get_max();
if min > max {
let Some(nearest_matching_cell) = nearest_matching_cell else {
let Some(nearest_matching_cell) = self.seek_state.get_nearest_matching_cell()
else {
return Ok(CursorResult::Ok(CursorHasRecord::No));
};
let matching_cell = contents.cell_get(
@@ -1827,28 +1919,28 @@ impl BTreeCursor {
}
if found {
self.seek_state
.set_nearest_matching_cell(Some(cur_cell_idx as usize));
match iter_dir {
IterationDirection::Forwards => {
nearest_matching_cell = Some(cur_cell_idx as usize);
max = cur_cell_idx - 1;
self.seek_state.set_max(cur_cell_idx - 1);
}
IterationDirection::Backwards => {
nearest_matching_cell = Some(cur_cell_idx as usize);
min = cur_cell_idx + 1;
self.seek_state.set_min(cur_cell_idx + 1);
}
}
} else {
if cmp.is_gt() {
max = cur_cell_idx - 1;
self.seek_state.set_max(cur_cell_idx - 1);
} else if cmp.is_lt() {
min = cur_cell_idx + 1;
self.seek_state.set_min(cur_cell_idx + 1);
} else {
match iter_dir {
IterationDirection::Forwards => {
min = cur_cell_idx + 1;
self.seek_state.set_min(cur_cell_idx + 1);
}
IterationDirection::Backwards => {
max = cur_cell_idx - 1;
self.seek_state.set_max(cur_cell_idx - 1);
}
}
}
@@ -1869,19 +1961,31 @@ impl BTreeCursor {
let page = page.get();
let contents = page.get().contents.as_ref().unwrap();
let cell_count = contents.cell_count();
let mut min: isize = 0;
let mut max: isize = cell_count as isize - 1;
if matches!(self.seek_state, CursorSeekState::Start) {
let min: isize = 0;
let max: isize = cell_count as isize - 1;
// If iter dir is forwards, we want the first cell that matches;
// If iter dir is backwards, we want the last cell that matches.
let nearest_matching_cell = None;
self.seek_state = CursorSeekState::Seeking {
min,
max,
nearest_matching_cell,
};
}
let iter_dir = seek_op.iteration_direction();
// If iter dir is forwards, we want the first cell that matches;
// If iter dir is backwards, we want the last cell that matches.
let mut nearest_matching_cell = None;
loop {
let min = self.seek_state.get_min();
let max = self.seek_state.get_max();
if min > max {
let Some(nearest_matching_cell) = nearest_matching_cell else {
let Some(nearest_matching_cell) = self.seek_state.get_nearest_matching_cell()
else {
// We have now iterated over all cells in the leaf page and found no match.
// Unlike tables, indexes store payloads in interior cells as well. self.move_to() always moves to a leaf page, so there are cases where we need to
// move back up to the parent interior cell and get the next record from there to perform a correct seek.
@@ -1972,16 +2076,18 @@ impl BTreeCursor {
self.get_immutable_record_or_create().as_mut().unwrap(),
)?
};
let record = self.get_immutable_record();
let record = record.as_ref().unwrap();
let record_slice_equal_number_of_cols =
&record.get_values().as_slice()[..key.get_values().len()];
let cmp = compare_immutable(
record_slice_equal_number_of_cols,
key.get_values(),
self.key_sort_order(),
&self.collations,
);
let cmp = {
let record = self.get_immutable_record();
let record = record.as_ref().unwrap();
let record_slice_equal_number_of_cols =
&record.get_values().as_slice()[..key.get_values().len()];
compare_immutable(
record_slice_equal_number_of_cols,
key.get_values(),
self.key_sort_order(),
&self.collations,
)
};
let found = match seek_op {
SeekOp::GT => cmp.is_gt(),
SeekOp::GE => cmp.is_ge(),
@@ -1990,28 +2096,28 @@ impl BTreeCursor {
SeekOp::LT => cmp.is_lt(),
};
if found {
self.seek_state
.set_nearest_matching_cell(Some(cur_cell_idx as usize));
match iter_dir {
IterationDirection::Forwards => {
nearest_matching_cell = Some(cur_cell_idx as usize);
max = cur_cell_idx - 1;
self.seek_state.set_max(cur_cell_idx - 1);
}
IterationDirection::Backwards => {
nearest_matching_cell = Some(cur_cell_idx as usize);
min = cur_cell_idx + 1;
self.seek_state.set_min(cur_cell_idx + 1);
}
}
} else {
if cmp.is_gt() {
max = cur_cell_idx - 1;
self.seek_state.set_max(cur_cell_idx - 1);
} else if cmp.is_lt() {
min = cur_cell_idx + 1;
self.seek_state.set_min(cur_cell_idx + 1);
} else {
match iter_dir {
IterationDirection::Forwards => {
min = cur_cell_idx + 1;
self.seek_state.set_min(cur_cell_idx + 1);
}
IterationDirection::Backwards => {
max = cur_cell_idx - 1;
self.seek_state.set_max(cur_cell_idx - 1);
}
}
}
@@ -3955,6 +4061,8 @@ impl BTreeCursor {
// on the outer loop.
self.set_null_flag(false);
let cursor_has_record = return_if_io!(self.do_seek(key, op));
// Reset seek state
self.seek_state = CursorSeekState::Start;
self.has_record.replace(cursor_has_record);
Ok(CursorResult::Ok(matches!(
cursor_has_record,

1
core/vdbe/execute.rs
View File

@@ -3907,6 +3907,7 @@ pub fn op_delete(
Ok(InsnFunctionStepResult::Step)
}
#[derive(Debug)]
pub enum OpIdxDeleteState {
Seeking(ImmutableRecord), // First seek row to delete
Deleting,