From 9b56778c495de3ed7b179083c926598ab5fbaf57 Mon Sep 17 00:00:00 2001 From: Andres Freund Date: Thu, 17 Oct 2024 11:50:13 -0400 Subject: [PATCH v1 05/14] 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 1748eafa100..d0cb4b1e29b 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); + tuple->t_self.ip_posid = lineoff; /* skip any tuples that don't match the scan key */ if (key != NULL && -- 2.46.0.519.g2e7b89e038