From 8e6dc7951708d65d993ec82618806ad39c7920ed Mon Sep 17 00:00:00 2001 From: Ivan Bykov Date: Fri, 24 Oct 2025 22:04:16 +0500 Subject: [PATCH] [PATCH v9] Introduce NextMultiXactId() --- src/backend/access/transam/multixact.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c index 17c95fc18fc..b4a3ff3bf83 100644 --- a/src/backend/access/transam/multixact.c +++ b/src/backend/access/transam/multixact.c @@ -219,6 +219,12 @@ PreviousMultiXactId(MultiXactId multi) return multi == FirstMultiXactId ? MaxMultiXactId : multi - 1; } +static inline MultiXactId +NextMultiXactId(MultiXactId multi) +{ + return multi == MaxMultiXactId ? FirstMultiXactId : multi + 1; +} + /* * Links to shared-memory data structures for MultiXact control */ @@ -909,7 +915,7 @@ RecordNewMultiXact(MultiXactId multi, MultiXactOffset offset, int i; LWLock *lock; LWLock *prevlock = NULL; - MultiXactId next = multi + 1; + MultiXactId next; int next_pageno; pageno = MultiXactIdToOffsetPage(multi); @@ -919,8 +925,7 @@ RecordNewMultiXact(MultiXactId multi, MultiXactOffset offset, * We must also fill next offset to keep current multi readable * Handle wraparound as GetMultiXactIdMembers() does it. */ - if (next < FirstMultiXactId) - next = FirstMultiXactId; + next = NextMultiXactId(multi); next_pageno = MultiXactIdToOffsetPage(next); lock = SimpleLruGetBankLock(MultiXactOffsetCtl, pageno); @@ -1165,7 +1170,7 @@ GetNewMultiXactId(int nmembers, MultiXactOffset *offset) } /* Make sure there is room for the MXID and next offset in the file. */ - ExtendMultiXactOffset(MultiXactState->nextMXact + 1); + ExtendMultiXactOffset(NextMultiXactId(MultiXactState->nextMXact)); /* * Reserve the members space, similarly to above. Also, be careful not to @@ -1275,7 +1280,8 @@ GetNewMultiXactId(int nmembers, MultiXactOffset *offset) * with either case. Similarly, nextOffset may be zero, but we won't use * that as the actual start offset of the next multixact. */ - (MultiXactState->nextMXact)++; + + MultiXactState->nextMXact = NextMultiXactId(MultiXactState->nextMXact); MultiXactState->nextOffset += nmembers; @@ -1455,7 +1461,7 @@ GetMultiXactIdMembers(MultiXactId multi, MultiXactMember **members, * Use the same increment rule as GetNewMultiXactId(), that is, don't * handle wraparound explicitly until needed. */ - tmpMXact = multi + 1; + tmpMXact = NextMultiXactId(multi); if (nextMXact == tmpMXact) { @@ -1466,10 +1472,6 @@ GetMultiXactIdMembers(MultiXactId multi, MultiXactMember **members, { MultiXactOffset nextMXOffset; - /* handle wraparound if needed */ - if (tmpMXact < FirstMultiXactId) - tmpMXact = FirstMultiXactId; - prev_pageno = pageno; pageno = MultiXactIdToOffsetPage(tmpMXact); @@ -3373,7 +3375,7 @@ multixact_redo(XLogReaderState *record) xlrec->members); /* Make sure nextMXact/nextOffset are beyond what this record has */ - MultiXactAdvanceNextMXact(xlrec->mid + 1, + MultiXactAdvanceNextMXact(NextMultiXactId(xlrec->mid), xlrec->moff + xlrec->nmembers); /* -- 2.39.5