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fix prev?

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This commit is contained in:
Pere Diaz Bou
2025-06-04 17:00:57 +02:00
committed by Jussi Saurio
parent f83d837131
commit 0f79b0dd50
1 changed files with 42 additions and 24 deletions
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66
core/storage/btree.rs
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@@ -736,6 +736,46 @@ impl BTreeCursor {
loop {
let page = self.stack.top();
return_if_locked_maybe_load!(self.pager, page);
let page = page.get();
let contents = page.get().contents.as_ref().unwrap();
let cell_count = contents.cell_count();
let cell_idx = self.stack.current_cell_index() as usize;
// dbg!(
// page.get().id,
// self.stack.current_cell_index(),
// self.going_upwards,
// page.get_contents().cell_count()
// );
// If we are at the end of the page and we haven't just come back from the right child,
// we now need to move to the rightmost child.
if self.stack.current_cell_index() == i32::MAX && !self.going_upwards {
let rightmost_pointer = contents.rightmost_pointer();
if let Some(rightmost_pointer) = rightmost_pointer {
self.stack
.push_backwards(self.read_page(rightmost_pointer as usize)?);
continue;
}
}
if cell_idx >= cell_count {
self.stack.set_cell_index(cell_count as i32 - 1);
} else {
let is_index = page.is_index();
// skip retreat in case we still haven't visited this cell in index
let should_visit_internal_node = is_index && self.going_upwards; // we are going upwards, this means we still need to visit divider cell in an index
let page_type = contents.page_type();
if should_visit_internal_node {
self.going_upwards = false;
return Ok(CursorResult::Ok(true));
} else if matches!(
page_type,
PageType::IndexLeaf | PageType::TableLeaf | PageType::TableInterior
) {
self.stack.retreat();
}
}
// moved to beginning of current page
// todo: find a better way to flag moved to end or begin of page
if self.stack.current_cell_index_less_than_min() {
@@ -748,35 +788,13 @@ impl BTreeCursor {
self.stack.pop();
} else {
// moved to begin of btree
// dbg!(false);
return Ok(CursorResult::Ok(false));
}
}
// continue to next loop to get record from the new page
continue;
}
return_if_locked_maybe_load!(self.pager, page);
self.stack.retreat();
let page = page.get();
let contents = page.get().contents.as_ref().unwrap();
let cell_count = contents.cell_count();
let cell_idx = self.stack.current_cell_index() as usize;
// If we are at the end of the page and we haven't just come back from the right child,
// we now need to move to the rightmost child.
if cell_idx as i32 == i32::MAX && !self.going_upwards {
let rightmost_pointer = contents.rightmost_pointer();
if let Some(rightmost_pointer) = rightmost_pointer {
self.stack
.push_backwards(self.read_page(rightmost_pointer as usize)?);
continue;
}
}
if cell_idx >= cell_count {
self.stack.set_cell_index(cell_count as i32 - 1);
}
let cell_idx = self.stack.current_cell_index() as usize;
let cell = contents.cell_get(
@@ -810,7 +828,7 @@ impl BTreeCursor {
// left child has: key 663, key 664, key 665
// we need to move to the previous parent (with e.g. key 662) when iterating backwards.
let mem_page = self.read_page(left_child_page as usize)?;
self.stack.advance();
self.stack.retreat();
self.stack.push_backwards(mem_page);
continue;
}