v9-0005-Move-shared-fileset-cleanup-to-before_shmem_exit.patch

From d90648909d7db6abf4938a4cbdfa8c3705235e7f Mon Sep 17 00:00:00 2001
From: Masahiko Sawada <sawada.mshk@gmail.com>
Date: Thu, 12 Aug 2021 10:57:41 +0900
Subject: [PATCH v9 5/5] Move shared fileset cleanup to before_shmem_exit().

The reported problem is that shared file set created in
SharedFileSetInit() by logical replication apply worker is cleaned up
in SharedFileSetDeleteOnProcExit() when the process exited on an error
due to a conflict. As shared fileset cleanup causes pgstat reporting
for underlying temporary files, the assertions added in ee3f8d3d3ae
caused failures.

To fix the problem, similar to 675c945394, move shared fileset cleanup
to a before_shmem_exit() hook, ensuring that the fileset is dropped
while we can still report stats for underlying temporary files.
---
 src/backend/storage/file/sharedfileset.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/backend/storage/file/sharedfileset.c b/src/backend/storage/file/sharedfileset.c
index ed37c940ad..0d9700bf56 100644
--- a/src/backend/storage/file/sharedfileset.c
+++ b/src/backend/storage/file/sharedfileset.c
@@ -36,7 +36,7 @@
 static List *filesetlist = NIL;
 
 static void SharedFileSetOnDetach(dsm_segment *segment, Datum datum);
-static void SharedFileSetDeleteOnProcExit(int status, Datum arg);
+static void SharedFileSetDeleteBeforeShmemExit(int status, Datum arg);
 static void SharedFileSetPath(char *path, SharedFileSet *fileset, Oid tablespace);
 static void SharedFilePath(char *path, SharedFileSet *fileset, const char *name);
 static Oid	ChooseTablespace(const SharedFileSet *fileset, const char *name);
@@ -112,7 +112,12 @@ SharedFileSetInit(SharedFileSet *fileset, dsm_segment *seg)
 			 * fileset clean up.
 			 */
 			Assert(filesetlist == NIL);
-			on_proc_exit(SharedFileSetDeleteOnProcExit, 0);
+
+			/*
+			 * Register before-shmem-exit hook to ensure fileset is dropped
+			 * while we can still report stats for underlying temporary files.
+			 */
+			before_shmem_exit(SharedFileSetDeleteBeforeShmemExit, 0);
 			registered_cleanup = true;
 		}
 
@@ -259,12 +264,12 @@ SharedFileSetOnDetach(dsm_segment *segment, Datum datum)
 }
 
 /*
- * Callback function that will be invoked on the process exit.  This will
+ * Callback function that will be invoked before shmem exit.  This will
  * process the list of all the registered sharedfilesets and delete the
  * underlying files.
  */
 static void
-SharedFileSetDeleteOnProcExit(int status, Datum arg)
+SharedFileSetDeleteBeforeShmemExit(int status, Datum arg)
 {
 	/*
 	 * Remove all the pending shared fileset entries. We don't use foreach()
-- 
2.24.3 (Apple Git-128)