From acc54c0839baede43d821a8e43e67d6b0ff1e4ed Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Thu, 17 Oct 2024 11:50:13 -0400 Subject: [PATCH v2 05/15] heapam: Only set tuple's block once per page in pagemode Due to splitting the block id into two 16 bit integers, BlockIdSet() is more expensive than one might think. Doing it once per returned shows up as small but relibly reproducible cost. It's simple enough to just set the block number so once per block in pagemode, so do so. Author: Reviewed-by: Discussion: https://postgr.es/m/ Backpatch: --- src/backend/access/heap/heapam.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c index d00300c5dcb..f9086369728 100644 --- a/src/backend/access/heap/heapam.c +++ b/src/backend/access/heap/heapam.c @@ -981,6 +981,9 @@ heapgettup_pagemode(HeapScanDesc scan, linesleft = scan->rs_ntuples; lineindex = ScanDirectionIsForward(dir) ? 0 : linesleft - 1; + /* set block once per page, instead of doing so for every tuple */ + BlockIdSet(&tuple->t_self.ip_blkid, scan->rs_cblock); + /* lineindex now references the next or previous visible tid */ continue_page: @@ -995,7 +998,7 @@ continue_page: tuple->t_data = (HeapTupleHeader) PageGetItem(page, lpp); tuple->t_len = ItemIdGetLength(lpp); - ItemPointerSet(&(tuple->t_self), scan->rs_cblock, lineoff); + ItemPointerSetOffsetNumber(&tuple->t_self, lineoff); /* skip any tuples that don't match the scan key */ if (key != NULL && -- 2.45.2.746.g06e570c0df.dirty