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help / color / mirror / Atom feedFrom: Maxim Orlov <[email protected]>
To: Anton A. Melnikov <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: Maybe don't process multi xmax in FreezeMultiXactId() if it is already marked as invalid?
Date: Tue, 18 Jun 2024 17:29:13 +0300
Message-ID: <CACG=ezbB2q2wYZseBA5mcNKXZwamPRb2dzzqrRtJ37E=K7do2w@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
<[email protected]>
Hi!
Maybe, I'm too bold, but looks like a kinda bug to me. At least, I don't
understand why we do not check the HEAP_XMAX_INVALID flag.
My guess is nobody noticed, that MultiXactIdIsValid call does not check the
mentioned flag in the "first" condition, but it's all my speculation.
Does anyone know if there are reasons to deliberately ignore the HEAP_XMAX
INVALID flag? Or this is just an unfortunate oversight.
PFA, my approach on this issue.
--
Best regards,
Maxim Orlov.
Attachments:
[application/octet-stream] v2-0001-Invalidate-xmax-if-HEAP_XMAX_INVALID-is-set.patch (772B, ../CACG=ezbB2q2wYZseBA5mcNKXZwamPRb2dzzqrRtJ37E=K7do2w@mail.gmail.com/3-v2-0001-Invalidate-xmax-if-HEAP_XMAX_INVALID-is-set.patch)
download | inline diff:
From 90867d80a081de1509dc57938e39ed02649f88ab Mon Sep 17 00:00:00 2001
From: Maxim Orlov <[email protected]>
Date: Tue, 18 Jun 2024 17:17:06 +0300
Subject: [PATCH v2] Invalidate xmax if HEAP_XMAX_INVALID is set.
---
src/backend/access/heap/heapam.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 82bb9cb33b6..0c4db5b225f 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -6216,6 +6216,7 @@ FreezeMultiXactId(MultiXactId multi, uint16 t_infomask,
Assert(t_infomask & HEAP_XMAX_IS_MULTI);
if (!MultiXactIdIsValid(multi) ||
+ (t_infomask & HEAP_XMAX_INVALID) ||
HEAP_LOCKED_UPGRADED(t_infomask))
{
*flags |= FRM_INVALIDATE_XMAX;
--
2.45.2
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Subject: Re: Maybe don't process multi xmax in FreezeMultiXactId() if it is already marked as invalid?
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