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btree/fix: use correct byte offsets for page1 in defragmentation

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`defragment_page_fast()` incorrectly didn't use the version of
read/write methods on `PageContent` that does NOT add the 100 byte
database header into the requested byte offset.

this resulted in defragment of page 1 in reading 2nd/3rd freeblocks
from the wrong offset and writing cell offsets to the wrong location.
This commit is contained in:
Jussi Saurio
2025-08-07 15:36:07 +03:00
parent aca02c9969
commit 6cd7334afc
1 changed files with 7 additions and 7 deletions
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14
core/storage/btree.rs
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@@ -6498,9 +6498,9 @@ fn defragment_page_fast(
turso_assert!(freeblock_1st <= usable_space as usize - FREEBLOCK_SIZE_MIN, "1st freeblock beyond usable space: freeblock_1st={freeblock_1st} usable_space={usable_space}");
turso_assert!(freeblock_2nd <= usable_space as usize - FREEBLOCK_SIZE_MIN, "2nd freeblock beyond usable space: freeblock_2nd={freeblock_2nd} usable_space={usable_space}");
let freeblock_1st_size = page.read_u16(freeblock_1st + 2) as usize;
let freeblock_1st_size = page.read_u16_no_offset(freeblock_1st + 2) as usize;
let freeblock_2nd_size = if freeblock_2nd > 0 {
page.read_u16(freeblock_2nd + 2) as usize
page.read_u16_no_offset(freeblock_2nd + 2) as usize
} else {
0
};
@@ -6552,19 +6552,19 @@ fn defragment_page_fast(
let cell_pointer_array_offset = page.cell_pointer_array_offset_and_size().0;
for i in 0..cell_count {
let ptr_offset = cell_pointer_array_offset + (i * CELL_PTR_SIZE_BYTES);
let cell_ptr = page.read_u16(ptr_offset) as usize;
let cell_ptr = page.read_u16_no_offset(ptr_offset) as usize;
if cell_ptr < freeblock_1st {
// If the cell pointer was located before the first freeblock, we need to shift it right by the size of the merged freeblock
// since the space occupied by both the 1st and 2nd freeblocks was now moved to its left.
let new_offset = cell_ptr + freeblocks_total_size;
turso_assert!(new_offset <= usable_space as usize, "new offset beyond usable space: new_offset={new_offset} usable_space={usable_space}");
page.write_u16(ptr_offset, (cell_ptr + freeblocks_total_size) as u16);
page.write_u16_no_offset(ptr_offset, (cell_ptr + freeblocks_total_size) as u16);
} else if freeblock_2nd > 0 && cell_ptr < freeblock_2nd {
// If the cell pointer was located between the first and second freeblock, we need to shift it right by the size of only the second freeblock,
// since the first one was already on its left.
let new_offset = cell_ptr + freeblock_2nd_size;
turso_assert!(new_offset <= usable_space as usize, "new offset beyond usable space: new_offset={new_offset} usable_space={usable_space}");
page.write_u16(ptr_offset, (cell_ptr + freeblock_2nd_size) as u16);
page.write_u16_no_offset(ptr_offset, (cell_ptr + freeblock_2nd_size) as u16);
}
}
@@ -6606,11 +6606,11 @@ fn defragment_page(page: &PageContent, usable_space: u16, max_frag_bytes: isize)
// No freeblocks and very little if any fragmented free bytes -> no need to defragment.
return Ok(());
}
let freeblock_2nd = page.read_u16(freeblock_1st) as usize;
let freeblock_2nd = page.read_u16_no_offset(freeblock_1st) as usize;
if freeblock_2nd == 0 {
return defragment_page_fast(page, usable_space, freeblock_1st, 0);
}
let freeblock_3rd = page.read_u16(freeblock_2nd) as usize;
let freeblock_3rd = page.read_u16_no_offset(freeblock_2nd) as usize;
if freeblock_3rd == 0 {
return defragment_page_fast(page, usable_space, freeblock_1st, freeblock_2nd);
}