postgres.git / summary / log / commit / refs

commit    e2dd7b2acf27336d47f78d68f4aac03f7770a6a6
Author:   Michael Paquier <michael@paquier.xyz>
Date:     Tue Sep 09 22:23:24 2025 +0000
First released in: 17.7, 18.0

    Fix leak with SMgrRelations in startup process
    
    The startup process does not process shared invalidation messages, only
    sending them, and never calls AtEOXact_SMgr() which clean up any
    unpinned SMgrRelations.  Hence, it is never able to free SMgrRelations
    on a periodic basis, bloating its hashtable over time.
    
    Like the checkpointer and the bgwriter, this commit takes a conservative
    approach by freeing periodically SMgrRelations when replaying a
    checkpoint record, either online or shutdown, so as the startup process
    has a way to perform a periodic cleanup.
    
    Issue caused by 21d9c3ee4ef7, so backpatch down to v17.
    
    Author: Jingtang Zhang <mrdrivingduck@gmail.com>
    Reviewed-by: Yuhang Qiu <iamqyh@gmail.com>
    Discussion: https://postgr.es/m/28C687D4-F335-417E-B06C-6612A0BD5A10@gmail.com
    Backpatch-through: 17


 src/backend/access/transam/xlog.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/backend/access/transam/xlog.c b/src/backend/access/transam/xlog.c
index ffea4993177..09fe5272022 100644
--- a/src/backend/access/transam/xlog.c
+++ b/src/backend/access/transam/xlog.c
@@ -8374,6 +8374,14 @@ xlog_redo(XLogReaderState *record)
 							checkPoint.ThisTimeLineID, replayTLI)));
 
 		RecoveryRestartPoint(&checkPoint, record);
+
+		/*
+		 * After replaying a checkpoint record, free all smgr objects.
+		 * Otherwise we would never do so for dropped relations, as the
+		 * startup does not process shared invalidation messages or call
+		 * AtEOXact_SMgr().
+		 */
+		smgrdestroyall();
 	}
 	else if (info == XLOG_CHECKPOINT_ONLINE)
 	{
@@ -8432,6 +8440,14 @@ xlog_redo(XLogReaderState *record)
 							checkPoint.ThisTimeLineID, replayTLI)));
 
 		RecoveryRestartPoint(&checkPoint, record);
+
+		/*
+		 * After replaying a checkpoint record, free all smgr objects.
+		 * Otherwise we would never do so for dropped relations, as the
+		 * startup does not process shared invalidation messages or call
+		 * AtEOXact_SMgr().
+		 */
+		smgrdestroyall();
 	}
 	else if (info == XLOG_OVERWRITE_CONTRECORD)
 	{


[parent: 778f391c26c6]