Re: [HACKERS] Reproducible vacuum complaint!

From: Vadim Mikheev <vadim(at)krs(dot)ru>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Hiroshi Inoue <Inoue(at)tpf(dot)co(dot)jp>, pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: [HACKERS] Reproducible vacuum complaint!
Date: 1999-11-22 05:19:11
Message-ID: 3838D24F.DB274049@krs.ru
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Tom Lane wrote:
>
> "Hiroshi Inoue" <Inoue(at)tpf(dot)co(dot)jp> writes:
> > Hmm,if "select * .." runs in SERIALIZABLE isolation level,the transaction
> > would see an old "msg_id=42" tuple(not new one). So vacuum doesn't
> > vanish the old "msg_id=42" tuple. Vacuum takes all running transactions
> > into account. But AFAIK,there's no other such stuff.
> > CREATE INDEX may be another one which should take all running
> > transactions into account.
...
> It looks like btbuild() only indexes tuples that satisfy SnapshotNow,
> so this is definitely a potential problem for btree indexes. The other
> index types are likely broken in the same way...
>
> Comments anyone? What time qual should btbuild and friends be using,
> if not that?

Seems that we need in new

#define SnapshotAny ((Snapshot) 0x2)

and new HeapTupleSatisfiesAny() returning TRUE for any tuple
with valid and committed (or current xact id) t_xmin.

-:(

Sorry, I missed CREATE INDEX case.

Vadim
P.S. I'll comment about indices and vacuum latter...

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