Message-ID: <4B752A43.30503@enterprisedb.com>
Date: Fri, 12 Feb 2010 12:15:31 +0200
From: Heikki Linnakangas <heikki.linnakangas@enterprisedb.com>
Organization: EnterpriseDB
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To: Fujii Masao <masao.fujii@gmail.com>
CC: PostgreSQL-development <pgsql-hackers@postgresql.org>
Subject: Re: Streaming Replication docs
References: <4B751BEA.7000202@enterprisedb.com>
	<3f0b79eb1002120209i3afd935exd2e875ac11df19d7@mail.gmail.com>
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Fujii Masao wrote:
> We might need to add the following code of pg_standby into the core,
> to prefer it for many cases.
> 
>> #ifdef WIN32
>>
>> 			/*
>> 			 * Windows 'cp' sets the final file size before the copy is
>> 			 * complete, and not yet ready to be opened by pg_standby. So we
>> 			 * wait for sleeptime secs before attempting to restore. If that
>> 			 * is not enough, we will rely on the retry/holdoff mechanism.
>> 			 * GNUWin32's cp does not have this problem.
>> 			 */
>> 			pg_usleep(sleeptime * 1000000L);
>> #endif

That's actually a bit questionable, always has been even in pg_standby.
It adds a constant 1 s delay to the recovery each WAL file, which
effectively rate-limits the WAL recovery to 16MB per second. I think we
should rather add a warning to the docs, suggesting the copy-then-rename
method on Windows.

-- 
  Heikki Linnakangas
  EnterpriseDB   http://www.enterprisedb.com