From: Tom Lane <tgl@sss.pgh.pa.us>
To: Alvaro Herrera <alvherre@alvh.no-ip.org>
cc: =?utf-8?B?5b2t5pix5YKR?= <k872892@gmail.com>,
        pgsql-performance@postgresql.org
Subject: Re: Too many .history file in pg_xlog takes lots of space
In-reply-to: <20180314134958.yzp2pze2s2yajf7k@alvherre.pgsql>
References: <20180314134958.yzp2pze2s2yajf7k@alvherre.pgsql>
Comments: In-reply-to Alvaro Herrera <alvherre@alvh.no-ip.org>
	message dated "Wed, 14 Mar 2018 10:49:58 -0300"
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Date: Wed, 14 Mar 2018 11:29:44 -0400
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Alvaro Herrera <alvherre@alvh.no-ip.org> writes:
> 彭昱傑 wrote:
>> Every time I restart postgre server, it generates a new history file:

> That's strange -- it shouldn't happen ... sounds like you're causing a
> crash each time you restart.  Are you using immediate mode in shutdown
> maybe?  If so, don't; use fast mode instead.

I'm confused by this report too.  Plain crashes shouldn't result in
forking a new timeline.  To check, I tried "-m immediate", as well as
"kill -9 postmaster", and neither of those resulted in a new .history file
on restart.  I wonder if the OP's restart process involves calling
pg_resetxlog or something like that (which would be risky as heck).

			regards, tom lane