From a586cc4b6c568e88a459f1a69ac82aa42af7e5ba Mon Sep 17 00:00:00 2001
From: Andres Freund <andres@anarazel.de>
Date: Fri, 4 Oct 2019 13:08:51 -0700
Subject: [PATCH] Use a fd opened for read/write when syncing slots during
startup, take 2.
Cribbing from dfbaed45975:
Some operating systems, including the reporter's windows, return EBADFD
or similar when fsync() is invoked on a O_RDONLY file descriptor.
Unfortunately RestoreSlotFromDisk() does exactly that; which causes
failures after restarts in at least some scenarios.
If you hit the bug the error message will be something like
ERROR: could not fsync file "pg_replslot/$name/state": Bad file descriptor
Simply use O_RDWR instead of O_RDONLY when opening the relevant file
descriptor to fix the bug.
Unfortunately this fix was undone in 82a5649fb9db. Re-apply, and add a
comment.
Bug: 16039
Reported-By: Hans Buschmann
Author: Andres Freund
Discussion: https://postgr.es/m/16039-196fc97cc05e141c@postgresql.org
Backpatch: 12-, as 82a5649fb9db
---
src/backend/replication/slot.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/src/backend/replication/slot.c b/src/backend/replication/slot.c
index b1bcd93345d..21ae8531b3c 100644
--- a/src/backend/replication/slot.c
+++ b/src/backend/replication/slot.c
@@ -1386,7 +1386,8 @@ RestoreSlotFromDisk(const char *name)
elog(DEBUG1, "restoring replication slot from \"%s\"", path);
- fd = OpenTransientFile(path, O_RDONLY | PG_BINARY);
+ /* on some operating systems fsyncing a file requires O_RDWR */
+ fd = OpenTransientFile(path, O_RDWR | PG_BINARY);
/*
* We do not need to handle this as we are rename()ing the directory into
--
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