From: Michael Paquier <michael@paquier.xyz>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>
Cc: Jeff Davis <pgsql@j-davis.com>
Cc: Alexander Lakhin <exclusion@gmail.com>
Cc: Heikki Linnakangas <hlinnaka@iki.fi>
Cc: pgsql-hackers@postgresql.org
Subject: Re: Is this a problem in GenericXLogFinish()?
Date: Sat, 28 Oct 2023 20:00:00 +0900
Message-ID: <ZTzpsFEV3DhlmxX5@paquier.xyz> (raw)
In-Reply-To: <CAA4eK1+5jacq3g-fcVM2VTKt72SerQ5XuGV5rcrVNG1q7Shr+A@mail.gmail.com>
References: <CA+TgmoY+dagCyrMKau7UQeQU6w4LuVEu+yjsmJBoXKAo6XbUUA@mail.gmail.com>
<4b2dfe9c67713413a06be761f677bc34222afcb4.camel@j-davis.com>
<CA+TgmobjyWDQfiMLj1_Lf0GheiY0SaOEPbFEepfa3G-XOLmHOA@mail.gmail.com>
<23d87b531fab74e69fd753791a7e5047f17da9ab.camel@j-davis.com>
<f045c8f7-ee24-ead6-3679-c04a43d21351@gmail.com>
<8a1c93b33b6e0aac92b771339cce520eac0adf96.camel@j-davis.com>
<ZToVxyLSVUisFPp0@paquier.xyz>
<CA+TgmoZ8X60+mR4jhS4LoQ1Jf-amSS0xCyfu=p7f94t7HoiH2g@mail.gmail.com>
<ZTsBF-TKekQIFeL6@paquier.xyz>
<CAA4eK1+5jacq3g-fcVM2VTKt72SerQ5XuGV5rcrVNG1q7Shr+A@mail.gmail.com>
On Sat, Oct 28, 2023 at 03:45:13PM +0530, Amit Kapila wrote:
> Yes, we need it to exclude any concurrent in-progress scans that could
> return incorrect tuples during bucket squeeze operation.
Thanks. So I assume that we should just set REGBUF_NO_CHANGE when the
primary and write buffers are the same and there are no tuples to
move. Say with something like the attached?
--
Michael
Attachments:fix-hash-replay.patch (text/x-diff, 1.1K) downloaddiff --git a/src/backend/access/hash/hashovfl.c b/src/backend/access/hash/hashovfl.cindex 9d1ff20b92..9928068179 100644--- a/src/backend/access/hash/hashovfl.c+++ b/src/backend/access/hash/hashovfl.c@@ -647,6 +647,7 @@ _hash_freeovflpage(Relation rel, Buffer bucketbuf, Buffer ovflbuf,
xl_hash_squeeze_page xlrec;
XLogRecPtr recptr;
int i;
+ int wbuf_flags;
xlrec.prevblkno = prevblkno;
xlrec.nextblkno = nextblkno;
@@ -668,7 +669,15 @@ _hash_freeovflpage(Relation rel, Buffer bucketbuf, Buffer ovflbuf,
XLogRegisterBuffer(0, bucketbuf, flags);
}
- XLogRegisterBuffer(1, wbuf, REGBUF_STANDARD);+ /*+ * If the bucket buffer and the primary buffer are the same, a cleanup+ * lock is still required on the write buffer even if there no tuples+ * to move, so it needs to be registered in this case.+ */+ wbuf_flags = REGBUF_STANDARD;+ if (xlrec.is_prim_bucket_same_wrt && xlrec.ntups == 0)+ wbuf_flags |= REGBUF_NO_CHANGE;+ XLogRegisterBuffer(1, wbuf, wbuf_flags);
if (xlrec.ntups > 0)
{
XLogRegisterBufData(1, (char *) itup_offsets,
signature.asc (application/pgp-signature, 832B) download
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To: pgsql-hackers@postgresql.org
Cc: michael@paquier.xyz, amit.kapila16@gmail.com, robertmhaas@gmail.com, pgsql@j-davis.com, exclusion@gmail.com, hlinnaka@iki.fi
Subject: Re: Is this a problem in GenericXLogFinish()?
In-Reply-To: <ZTzpsFEV3DhlmxX5@paquier.xyz>
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