Track SLRU page hits in SimpleLruReadPage_ReadOnly

tvondra · tvondra · commit 2b88fdde30d8 · 2020-04-08T02:15:47.000+02:00
SLRU page hits were tracked only in SimpleLruReadPage, but that's not enough because we may hit the page in SimpleLruReadPage_ReadOnly in which case we don't call SimpleLruReadPage at all. Reported-by: Kuntal Ghosh Discussion: https://postgr.es/m/20200119143707.gyinppnigokesjok@development
diff --git a/src/backend/access/transam/slru.c b/src/backend/access/transam/slru.c
@@ -491,6 +491,10 @@ SimpleLruReadPage_ReadOnly(SlruCtl ctl, int pageno, TransactionId xid)
 		{
 			/* See comments for SlruRecentlyUsed macro */
 			SlruRecentlyUsed(shared, slotno);
+
+			/* update the stats counter of pages found in the SLRU */
+			pgstat_count_slru_page_hit(ctl);
+
 			return slotno;
 		}
 	}

Original file line number	Diff line number	Diff line change
`@@ -491,6 +491,10 @@ SimpleLruReadPage_ReadOnly(SlruCtl ctl, int pageno, TransactionId xid)`
`491`	`491`	`{`
`492`	`492`	`/* See comments for SlruRecentlyUsed macro */`
`493`	`493`	`SlruRecentlyUsed(shared, slotno);`
	`494`	`+`
	`495`	`+ /* update the stats counter of pages found in the SLRU */`
	`496`	`+ pgstat_count_slru_page_hit(ctl);`
	`497`	`+`
`494`	`498`	`return slotno;`
`495`	`499`	`}`
`496`	`500`	`}`