From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@commandprompt.com>
Cc: ITAGAKI Takahiro <itagaki.takahiro@oss.ntt.co.jp>
Cc: pgsql-hackers@postgresql.org, Katsuhiko Okano <okano.katsuhiko@oss.ntt.co.jp>
Subject: Re: CSStorm occurred again by postgreSQL8.2
Date: Mon, 07 Aug 2006 16:27:41 -0400
Message-ID: <22293.1154982461@sss.pgh.pa.us> (raw)
In-Reply-To: <20060807201014.GB32736@alvh.no-ip.org>
References: <200607181650.EDC81237.LOBJUTPuIPPBLLV@oss.ntt.co.jp>
<5126.1153241513@sss.pgh.pa.us>
<20060807114525.5266.ITAGAKI.TAKAHIRO@oss.ntt.co.jp>
<19738.1154956177@sss.pgh.pa.us>
<20060807185243.GB26021@alvh.no-ip.org>
<13175.1154979751@sss.pgh.pa.us>
<20060807201014.GB32736@alvh.no-ip.org>
Alvaro Herrera <alvherre@commandprompt.com> writes:
> I was thinking at what time was the most appropiate to insert or remove
> an Xid from the cache. We can do without any excl-locking because 1) we
> already assume the storing of an Xid to be atomic, and 2) no one can be
> interested in querying for an Xid before the originating transaction has
> had the chance to write a tuple with that Xid anyway.
Actually ... that fails if GetSnapshotData is going to copy subtrans
XIDs. So this area needs more thought.
> On the third hand, are we going to sh-acquire the ProcArray lock while a
> GetSnapshotData copies all subxact Xids of all running transactions?
> ProcArrayLock will become more of a contention point than it already is.
Yeah, but sharelock is better than exclusive lock ...
regards, tom lane
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To: pgsql-hackers@postgresql.org
Cc: tgl@sss.pgh.pa.us, alvherre@commandprompt.com, itagaki.takahiro@oss.ntt.co.jp, okano.katsuhiko@oss.ntt.co.jp
Subject: Re: CSStorm occurred again by postgreSQL8.2
In-Reply-To: <22293.1154982461@sss.pgh.pa.us>
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