From 512230a98874d74833cb9856581c2ec71900cd31 Mon Sep 17 00:00:00 2001 From: Melanie Plageman Date: Thu, 21 Nov 2024 18:36:05 -0500 Subject: [PATCH v3 2/3] Make visibilitymap_set() return previous state of vmbits It can be useful to know the state of a relation page's VM bits before visibilitymap_set(). visibilitymap_set() has the old value on hand, so returning it is simple. This commit does not use visibilitymap_set()'s new return value. Author: Melanie Plageman Reviewed-by: Masahiko Sawada, Andres Freund, Nitin Jadhav Discussion: https://postgr.es/m/flat/CAAKRu_ZQe26xdvAqo4weHLR%3DivQ8J4xrSfDDD8uXnh-O-6P6Lg%40mail.gmail.com#6d8d2b4219394f774889509bf3bdc13d, https://postgr.es/m/ctdjzroezaxmiyah3gwbwm67defsrwj2b5fpfs4ku6msfpxeia%40mwjyqlhwr2wu --- src/backend/access/heap/visibilitymap.c | 9 +++++++-- src/include/access/visibilitymap.h | 9 ++++++--- 2 files changed, 13 insertions(+), 5 deletions(-) diff --git a/src/backend/access/heap/visibilitymap.c b/src/backend/access/heap/visibilitymap.c index 8b24e7bc33c..5f71fafaa37 100644 --- a/src/backend/access/heap/visibilitymap.c +++ b/src/backend/access/heap/visibilitymap.c @@ -239,8 +239,10 @@ visibilitymap_pin_ok(BlockNumber heapBlk, Buffer vmbuf) * You must pass a buffer containing the correct map page to this function. * Call visibilitymap_pin first to pin the right one. This function doesn't do * any I/O. + * + * Returns the state of the page's VM bits before setting flags. */ -void +uint8 visibilitymap_set(Relation rel, BlockNumber heapBlk, Buffer heapBuf, XLogRecPtr recptr, Buffer vmBuf, TransactionId cutoff_xid, uint8 flags) @@ -250,6 +252,7 @@ visibilitymap_set(Relation rel, BlockNumber heapBlk, Buffer heapBuf, uint8 mapOffset = HEAPBLK_TO_OFFSET(heapBlk); Page page; uint8 *map; + uint8 status; #ifdef TRACE_VISIBILITYMAP elog(DEBUG1, "vm_set %s %d", RelationGetRelationName(rel), heapBlk); @@ -274,7 +277,8 @@ visibilitymap_set(Relation rel, BlockNumber heapBlk, Buffer heapBuf, map = (uint8 *) PageGetContents(page); LockBuffer(vmBuf, BUFFER_LOCK_EXCLUSIVE); - if (flags != (map[mapByte] >> mapOffset & VISIBILITYMAP_VALID_BITS)) + status = ((map[mapByte] >> mapOffset) & VISIBILITYMAP_VALID_BITS); + if (flags != status) { START_CRIT_SECTION(); @@ -311,6 +315,7 @@ visibilitymap_set(Relation rel, BlockNumber heapBlk, Buffer heapBuf, } LockBuffer(vmBuf, BUFFER_LOCK_UNLOCK); + return status; } /* diff --git a/src/include/access/visibilitymap.h b/src/include/access/visibilitymap.h index 1a4d467e6f0..f7779a0fe19 100644 --- a/src/include/access/visibilitymap.h +++ b/src/include/access/visibilitymap.h @@ -31,9 +31,12 @@ extern bool visibilitymap_clear(Relation rel, BlockNumber heapBlk, extern void visibilitymap_pin(Relation rel, BlockNumber heapBlk, Buffer *vmbuf); extern bool visibilitymap_pin_ok(BlockNumber heapBlk, Buffer vmbuf); -extern void visibilitymap_set(Relation rel, BlockNumber heapBlk, Buffer heapBuf, - XLogRecPtr recptr, Buffer vmBuf, TransactionId cutoff_xid, - uint8 flags); +extern uint8 visibilitymap_set(Relation rel, + BlockNumber heapBlk, Buffer heapBuf, + XLogRecPtr recptr, + Buffer vmBuf, + TransactionId cutoff_xid, + uint8 flags); extern uint8 visibilitymap_get_status(Relation rel, BlockNumber heapBlk, Buffer *vmbuf); extern void visibilitymap_count(Relation rel, BlockNumber *all_visible, BlockNumber *all_frozen); extern BlockNumber visibilitymap_prepare_truncate(Relation rel, -- 2.45.2