[Daniel Shelepanov <deniel1495@mail.ru>]

Hi hackers!
 
I’ve been working on this [ https://www.postgresql.org/message-id/flat/cfcca574-6967-c5ab-7dc3-2c82b6723b99%40mail.ru ] bug. Finally, I’ve come up with the patch you can find attached. Basically what is does is rises a PROC_IN_VACUUM flag and resets it afterwards. I know this seems kinda crunchy and I hope you guys will give me some hints on where to continue. This [ https://www.postgresql.org/message-id/20220218175119.7hwv7ksamfjwijbx%40alap3.anarazel.de ] message contains reproduction script. Thank you very much in advance.
 
Kind regards,
Daniel Shelepanov

Attachments:

collect_corrupt_items_vacuum.patch (text/x-diff, 1.4K) download
diff --git a/contrib/pg_visibility/pg_visibility.c b/contrib/pg_visibility/pg_visibility.c
index 53aaf61cb94..700ebeaa018 100644
--- a/contrib/pg_visibility/pg_visibility.c
+++ b/contrib/pg_visibility/pg_visibility.c
@@ -18,6 +18,7 @@
 #include "funcapi.h"
 #include "miscadmin.h"
 #include "storage/bufmgr.h"
+#include "storage/proc.h"
 #include "storage/procarray.h"
 #include "storage/smgr.h"
 #include "utils/rel.h"
@@ -562,12 +563,19 @@ collect_corrupt_items(Oid relid, bool all_visible, bool all_frozen)
 	Buffer		vmbuffer = InvalidBuffer;
 	BufferAccessStrategy bstrategy = GetAccessStrategy(BAS_BULKREAD);
 	TransactionId OldestXmin = InvalidTransactionId;
+	uint8		oldStatusFlags;
 
 	rel = relation_open(relid, AccessShareLock);
 
 	/* Only some relkinds have a visibility map */
 	check_relation_relkind(rel);
 
+	LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
+	oldStatusFlags = MyProc->statusFlags;
+	MyProc->statusFlags |= PROC_IN_VACUUM;
+	ProcGlobal->statusFlags[MyProc->pgxactoff] = MyProc->statusFlags;
+	LWLockRelease(ProcArrayLock);
+
 	if (all_visible)
 		OldestXmin = GetOldestNonRemovableTransactionId(rel);
 
@@ -722,6 +730,11 @@ collect_corrupt_items(Oid relid, bool all_visible, bool all_frozen)
 	items->count = items->next;
 	items->next = 0;
 
+	LWLockAcquire(ProcArrayLock, LW_EXCLUSIVE);
+	MyProc->statusFlags = oldStatusFlags;
+	ProcGlobal->statusFlags[MyProc->pgxactoff] = MyProc->statusFlags;
+	LWLockRelease(ProcArrayLock);
+
 	return items;
 }