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Convert heap_vac_scan_next_block() boolean parameters to flags

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The read stream API only allows one piece of extra per block state to be
passed back to the API user (per_buffer_data). lazy_scan_heap() needs
two pieces of per-buffer data: whether or not the block was all-visible
in the visibility map and whether or not it was eagerly scanned.

Convert these two pieces of information to flags so that they can be
populated by heap_vac_scan_next_block() and returned to
lazy_scan_heap(). A future commit will turn heap_vac_scan_next_block()
into the read stream callback for heap phase I vacuuming.

Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/CAAKRu_bmx33jTqATP5GKNFYwAg02a9dDtk4U_ciEjgBHZSVkOQ%40mail.gmail.com
This commit is contained in:
Melanie Plageman
2025-02-14 12:56:50 -05:00
parent 977d865c36
commit 32acad7d1d
1 changed files with 27 additions and 20 deletions
Download Patch File Download Diff File Expand all files Collapse all files

47
src/backend/access/heap/vacuumlazy.c
View File

@ -248,6 +248,13 @@ typedef enum
*/
#define EAGER_SCAN_REGION_SIZE 4096
/*
* heap_vac_scan_next_block() sets these flags to communicate information
* about the block it read to the caller.
*/
#define VAC_BLK_WAS_EAGER_SCANNED (1 << 0)
#define VAC_BLK_ALL_VISIBLE_ACCORDING_TO_VM (1 << 1)
typedef struct LVRelState
{
/* Target heap relation and its indexes */
@ -417,8 +424,7 @@ static void lazy_scan_heap(LVRelState *vacrel);
static void heap_vacuum_eager_scan_setup(LVRelState *vacrel,
VacuumParams *params);
static bool heap_vac_scan_next_block(LVRelState *vacrel, BlockNumber *blkno,
bool *all_visible_according_to_vm,
bool *was_eager_scanned);
uint8 *blk_info);
static void find_next_unskippable_block(LVRelState *vacrel, bool *skipsallvis);
static bool lazy_scan_new_or_empty(LVRelState *vacrel, Buffer buf,
BlockNumber blkno, Page page,
@ -1171,8 +1177,7 @@ lazy_scan_heap(LVRelState *vacrel)
BlockNumber rel_pages = vacrel->rel_pages,
blkno,
next_fsm_block_to_vacuum = 0;
bool all_visible_according_to_vm,
was_eager_scanned = false;
uint8 blk_info = 0;
BlockNumber orig_eager_scan_success_limit =
vacrel->eager_scan_remaining_successes; /* for logging */
Buffer vmbuffer = InvalidBuffer;
@ -1196,8 +1201,7 @@ lazy_scan_heap(LVRelState *vacrel)
vacrel->next_unskippable_eager_scanned = false;
vacrel->next_unskippable_vmbuffer = InvalidBuffer;
while (heap_vac_scan_next_block(vacrel, &blkno, &all_visible_according_to_vm,
&was_eager_scanned))
while (heap_vac_scan_next_block(vacrel, &blkno, &blk_info))
{
Buffer buf;
Page page;
@ -1206,7 +1210,7 @@ lazy_scan_heap(LVRelState *vacrel)
bool got_cleanup_lock = false;
vacrel->scanned_pages++;
if (was_eager_scanned)
if (blk_info & VAC_BLK_WAS_EAGER_SCANNED)
vacrel->eager_scanned_pages++;
/* Report as block scanned, update error traceback information */
@ -1331,7 +1335,8 @@ lazy_scan_heap(LVRelState *vacrel)
*/
if (got_cleanup_lock)
lazy_scan_prune(vacrel, buf, blkno, page,
vmbuffer, all_visible_according_to_vm,
vmbuffer,
blk_info & VAC_BLK_ALL_VISIBLE_ACCORDING_TO_VM,
&has_lpdead_items, &vm_page_frozen);
/*
@ -1348,7 +1353,8 @@ lazy_scan_heap(LVRelState *vacrel)
* exclude pages skipped due to cleanup lock contention from eager
* freeze algorithm caps.
*/
if (got_cleanup_lock && was_eager_scanned)
if (got_cleanup_lock &&
(blk_info & VAC_BLK_WAS_EAGER_SCANNED))
{
/* Aggressive vacuums do not eager scan. */
Assert(!vacrel->aggressive);
@ -1479,11 +1485,11 @@ lazy_scan_heap(LVRelState *vacrel)
* and various thresholds to skip blocks which do not need to be processed and
* sets blkno to the next block to process.
*
* The block number and visibility status of the next block to process are set
* in *blkno and *all_visible_according_to_vm. The return value is false if
* there are no further blocks to process. If the block is being eagerly
* scanned, was_eager_scanned is set so that the caller can count whether or
* not an eagerly scanned page is successfully frozen.
* The block number of the next block to process is set in *blkno and its
* visibility status and whether or not it was eager scanned is set in
* *blk_info.
*
* The return value is false if there are no further blocks to process.
*
* vacrel is an in/out parameter here. Vacuum options and information about
* the relation are read. vacrel->skippedallvis is set if we skip a block
@ -1493,15 +1499,14 @@ lazy_scan_heap(LVRelState *vacrel)
*/
static bool
heap_vac_scan_next_block(LVRelState *vacrel, BlockNumber *blkno,
bool *all_visible_according_to_vm,
bool *was_eager_scanned)
uint8 *blk_info)
{
BlockNumber next_block;
/* relies on InvalidBlockNumber + 1 overflowing to 0 on first call */
next_block = vacrel->current_block + 1;
*was_eager_scanned = false;
*blk_info = 0;
/* Have we reached the end of the relation? */
if (next_block >= vacrel->rel_pages)
@ -1562,7 +1567,7 @@ heap_vac_scan_next_block(LVRelState *vacrel, BlockNumber *blkno,
* otherwise they would've been unskippable.
*/
*blkno = vacrel->current_block = next_block;
*all_visible_according_to_vm = true;
*blk_info |= VAC_BLK_ALL_VISIBLE_ACCORDING_TO_VM;
return true;
}
else
@ -1574,8 +1579,10 @@ heap_vac_scan_next_block(LVRelState *vacrel, BlockNumber *blkno,
Assert(next_block == vacrel->next_unskippable_block);
*blkno = vacrel->current_block = next_block;
*all_visible_according_to_vm = vacrel->next_unskippable_allvis;
*was_eager_scanned = vacrel->next_unskippable_eager_scanned;
if (vacrel->next_unskippable_allvis)
*blk_info |= VAC_BLK_ALL_VISIBLE_ACCORDING_TO_VM;
if (vacrel->next_unskippable_eager_scanned)
*blk_info |= VAC_BLK_WAS_EAGER_SCANNED;
return true;
}
}