Do not assign max(lsn) to maxLastWrittenLsn in SetLastWrittenLSNForBlockv

Konstantin Knizhnik · Konstantin Knizhnik · commit 46f9b96555e0 · 2025-01-24T12:20:29.000+02:00
diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
@@ -6938,6 +6938,7 @@ SetLastWrittenLSNForBlockv(const XLogRecPtr *lsns, RelFileLocator relfilenode,
 	LastWrittenLsnCacheEntry* entry;
 	BufferTag	key;
 	bool		found;
+	XLogRecPtr	max = InvalidXLogRecPtr;
 
 	if (lsns == NULL || nblocks == 0 || lastWrittenLsnCacheSize == 0 ||
 		relfilenode.relNumber == InvalidOid)
@@ -6981,11 +6982,12 @@ SetLastWrittenLSNForBlockv(const XLogRecPtr *lsns, RelFileLocator relfilenode,
 		}
 		/* Link to the end of LRU list */
 		dlist_push_tail(&XLogCtl->lastWrittenLsnLRU, &entry->lru_node);
+		max = Max(max, lsn);
 	}
 
 	LWLockRelease(LastWrittenLsnLock);
 
-	return lsn;
+	return max;
 }
 
 /*

Original file line number	Diff line number	Diff line change
`@@ -6938,6 +6938,7 @@ SetLastWrittenLSNForBlockv(const XLogRecPtr *lsns, RelFileLocator relfilenode,`
`6938`	`6938`	`LastWrittenLsnCacheEntry* entry;`
`6939`	`6939`	`BufferTag key;`
`6940`	`6940`	`bool found;`
	`6941`	`+ XLogRecPtr max = InvalidXLogRecPtr;`
`6941`	`6942`
`6942`	`6943`	`if (lsns == NULL \|\| nblocks == 0 \|\| lastWrittenLsnCacheSize == 0 \|\|`
`6943`	`6944`	`relfilenode.relNumber == InvalidOid)`
`@@ -6981,11 +6982,12 @@ SetLastWrittenLSNForBlockv(const XLogRecPtr *lsns, RelFileLocator relfilenode,`
`6981`	`6982`	`}`
`6982`	`6983`	`/* Link to the end of LRU list */`
`6983`	`6984`	`dlist_push_tail(&XLogCtl->lastWrittenLsnLRU, &entry->lru_node);`
	`6985`	`+ max = Max(max, lsn);`
`6984`	`6986`	`}`
`6985`	`6987`
`6986`	`6988`	`LWLockRelease(LastWrittenLsnLock);`
`6987`	`6989`
`6988`		`- return lsn;`
	`6990`	`+ return max;`
`6989`	`6991`	`}`
`6990`	`6992`
`6991`	`6993`	`/*`