From f2b06658c9bf9d610c68e75d01964852ff2adb78 Mon Sep 17 00:00:00 2001 From: Melanie Plageman Date: Mon, 28 Oct 2024 11:36:58 -0400 Subject: [PATCH v3 3/7] Remove superfluous next_block local variable in vacuum code Reduce the number of block related variables in lazy_scan_heap() and its helpers by removing the next_block local variable from heap_vac_scan_next_block(). --- src/backend/access/heap/vacuumlazy.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/src/backend/access/heap/vacuumlazy.c b/src/backend/access/heap/vacuumlazy.c index c9e8ed0e049..2d21ff7f0b8 100644 --- a/src/backend/access/heap/vacuumlazy.c +++ b/src/backend/access/heap/vacuumlazy.c @@ -1127,13 +1127,11 @@ static bool heap_vac_scan_next_block(LVRelState *vacrel, BlockNumber *blkno, bool *all_visible_according_to_vm) { - BlockNumber next_block; - /* relies on InvalidBlockNumber + 1 overflowing to 0 on first call */ - next_block = vacrel->current_block + 1; + vacrel->current_block++; /* Have we reached the end of the relation? */ - if (next_block >= vacrel->rel_pages) + if (vacrel->current_block >= vacrel->rel_pages) { *blkno = vacrel->rel_pages; return false; @@ -1142,7 +1140,7 @@ heap_vac_scan_next_block(LVRelState *vacrel, BlockNumber *blkno, /* * We must be in one of the three following states: */ - if (next_block > vacrel->next_unskippable_block || + if (vacrel->current_block > vacrel->next_unskippable_block || vacrel->next_unskippable_block == InvalidBlockNumber) { /* @@ -1169,23 +1167,24 @@ heap_vac_scan_next_block(LVRelState *vacrel, BlockNumber *blkno, * pages then skipping makes updating relfrozenxid unsafe, which is a * real downside. */ - if (vacrel->next_unskippable_block - next_block >= SKIP_PAGES_THRESHOLD) + if (vacrel->next_unskippable_block - vacrel->current_block >= + SKIP_PAGES_THRESHOLD) { - next_block = vacrel->next_unskippable_block; + vacrel->current_block = vacrel->next_unskippable_block; if (skipsallvis) vacrel->skippedallvis = true; } } /* Now we must be in one of the two remaining states: */ - if (next_block < vacrel->next_unskippable_block) + if (vacrel->current_block < vacrel->next_unskippable_block) { /* * 2. We are processing a range of blocks that we could have skipped * but chose not to. We know that they are all-visible in the VM, * otherwise they would've been unskippable. */ - *blkno = vacrel->current_block = next_block; + *blkno = vacrel->current_block; *all_visible_according_to_vm = true; return true; } @@ -1195,9 +1194,9 @@ heap_vac_scan_next_block(LVRelState *vacrel, BlockNumber *blkno, * 3. We reached the next unskippable block. Process it. On next * iteration, we will be back in state 1. */ - Assert(next_block == vacrel->next_unskippable_block); + Assert(vacrel->current_block == vacrel->next_unskippable_block); - *blkno = vacrel->current_block = next_block; + *blkno = vacrel->current_block; *all_visible_according_to_vm = vacrel->next_unskippable_allvis; return true; } -- 2.34.1