Date: Wed, 4 Jun 2014 14:10:22 -0400
From: Alvaro Herrera <alvherre@2ndquadrant.com>
To: Serge Negodyuck <petr@petrovich.kiev.ua>
Cc: pgsql-bugs@postgresql.org
Subject: Re: BUG #8673: Could not open file
 "pg_multixact/members/xxxx" on slave during hot_standby
Message-ID: <20140604181022.GQ5146@eldon.alvh.no-ip.org>
References: <20131209142525.GA1123@awork2.anarazel.de>
 <CABKyZDFWn+ty_m88sq2j5UThowb2Qwd0125BNx_19va2Fn57dQ@mail.gmail.com>
 <20131209150345.GB1123@awork2.anarazel.de>
 <CABKyZDFRtDzcY1=sEznC2ivmcM5p1yPQvC8qLL8XLviNF2kp7A@mail.gmail.com>
 <20131209182701.GD9519@awork2.anarazel.de>
 <20140103014616.GB7035@eldon.alvh.no-ip.org>
 <CABKyZDEV49nUYJej9Hv-hPUS=VUmMt1LmVV=YW=fV5X8nKtdtw@mail.gmail.com>
 <20140602141041.GS7857@eldon.alvh.no-ip.org>
 <CABKyZDFChThHcW+Xo75hAWjVhcRypRoCKKFhqYpoVUNHe15Fkw@mail.gmail.com>
 <20140604174659.GP5146@eldon.alvh.no-ip.org>
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Alvaro Herrera wrote:

> I wasn't able to reproduce it that way, but I eventually figured out
> that if I altered altered the plpython function to grab a FOR NO KEY
> UPDATE lock first, insertion would grow the multixact beyond reasonable
> limits; see the attachment.  If you then INSERT many tuples in "product"
> in a single transaction, the resulting xmax is a Multixact that has as
> many members as inserts there are, plus one.

Bah.  I managed to submit a file with the lock_company() call commented
out in the plpython function.  That one doesn't do anything interesting;
you need to uncomment that line.

-- 
Álvaro Herrera                http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services


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