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Re: pgsql: Reduce default value of max_prepared_transactions

From: Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>
To: Tom Lane <tgl(at)svr1(dot)postgresql(dot)org>
Cc: pgsql-committers(at)postgresql(dot)org
Subject: Re: pgsql: Reduce default value of max_prepared_transactions
Date: 2005-08-30 00:45:11
Message-ID: 200508300045.j7U0jCV09276@candle.pha.pa.us (view raw or flat)
Thread:
Lists: pgsql-committers
Should this be mentioned in the PREPARE TRANSACTION manual page?

---------------------------------------------------------------------------

Tom Lane wrote:
> Log Message:
> -----------
> Reduce default value of max_prepared_transactions from 50 to 5.  This
> saves nearly 700kB in the default shared memory segment size, which seems
> worthwhile, and it is a feature that many users won't use anyway.  Per
> Heikki's argument, there is no point in a compromise value --- those who
> are using 2PC at all will probably want it at least equal to max_connections.
> But we can't set it to zero by default without breaking the prepared_xacts
> regression test.
> 
> Modified Files:
> --------------
>     pgsql/doc/src/sgml:
>         runtime.sgml (r1.348 -> r1.349)
>         (http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/src/sgml/runtime.sgml.diff?r1=1.348&r2=1.349)
>     pgsql/src/backend/access/transam:
>         twophase.c (r1.10 -> r1.11)
>         (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/access/transam/twophase.c.diff?r1=1.10&r2=1.11)
>     pgsql/src/backend/utils/misc:
>         guc.c (r1.286 -> r1.287)
>         (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/guc.c.diff?r1=1.286&r2=1.287)
>         postgresql.conf.sample (r1.161 -> r1.162)
>         (http://developer.postgresql.org/cvsweb.cgi/pgsql/src/backend/utils/misc/postgresql.conf.sample.diff?r1=1.161&r2=1.162)
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 5: don't forget to increase your free space map settings
> 

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman(at)candle(dot)pha(dot)pa(dot)us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
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Next:From: Tom LaneDate: 2005-08-30 00:58:48
Subject: pgsql: Update documentation about shared memory sizing to reflect
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Subject: pgsql: Reduce default value of max_prepared_transactions from 50 to 5.

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