Search for SLRU page only in its own bank

alvherre · alvherre · commit 7b063ff26a5f · 2024-08-18T20:49:57.000-04:00
One of the two slot scans in SlruSelectLRUPage was not walking only the slots in the specific bank where the buffer could be; change it to do that. Oversight in 53c2a97. Author: Sergey Sargsyan <sergey.sargsyan.2001@gmail.com> Discussion: https://postgr.es/m/18582-5f301dd30ba91a38@postgresql.org
diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c
@@ -1184,7 +1184,7 @@ SlruSelectLRUPage(SlruCtl ctl, int64 pageno)
 		Assert(LWLockHeldByMe(SimpleLruGetBankLock(ctl, pageno)));
 
 		/* See if page already has a buffer assigned */
-		for (int slotno = 0; slotno < shared->num_slots; slotno++)
+		for (int slotno = bankstart; slotno < bankend; slotno++)
 		{
 			if (shared->page_status[slotno] != SLRU_PAGE_EMPTY &&
 				shared->page_number[slotno] == pageno)

Original file line number	Diff line number	Diff line change
`@@ -1184,7 +1184,7 @@ SlruSelectLRUPage(SlruCtl ctl, int64 pageno)`
`1184`	`1184`	`Assert(LWLockHeldByMe(SimpleLruGetBankLock(ctl, pageno)));`
`1185`	`1185`
`1186`	`1186`	`/* See if page already has a buffer assigned */`
`1187`		`- for (int slotno = 0; slotno < shared->num_slots; slotno++)`
	`1187`	`+ for (int slotno = bankstart; slotno < bankend; slotno++)`
`1188`	`1188`	`{`
`1189`	`1189`	`if (shared->page_status[slotno] != SLRU_PAGE_EMPTY &&`
`1190`	`1190`	`shared->page_number[slotno] == pageno)`