Re: pgsql: Use pg_pread() and pg_pwrite() for data files and WAL.

From: Andrew Dunstan <andrew(dot)dunstan(at)2ndquadrant(dot)com>
To: Thomas Munro <tmunro(at)postgresql(dot)org>, pgsql-committers(at)lists(dot)postgresql(dot)org
Subject: Re: pgsql: Use pg_pread() and pg_pwrite() for data files and WAL.
Date: 2018-11-06 22:32:21
Message-ID: 2d52ff4a-5440-f6f1-7806-423b0e6370cb@2ndQuadrant.com
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On 11/6/18 4:01 PM, Thomas Munro wrote:
> Use pg_pread() and pg_pwrite() for data files and WAL.
>
> Cut down on system calls by doing random I/O using offset-based OS
> routines where available. Remove the code for tracking the 'virtual'
> seek position. The only reason left to call FileSeek() was to get
> the file's size, so provide a new function FileSize() instead.

Getting this warning (gcc 8.2.1 Fedora 29):

Nov 06 17:18:55
/home/bf/bfr/root/HEAD/pgsql.build/../pgsql/src/backend/storage/file/fd.c:
In function ‘FileSize’:
Nov 06 17:18:55
/home/bf/bfr/root/HEAD/pgsql.build/../pgsql/src/backend/storage/file/fd.c:2007:11:
warning: variable ‘vfdP’ set but not used [-Wunused-but-set-variable]
Nov 06 17:18:55   Vfd     *vfdP;
Nov 06 17:18:55            ^~~~

cheers

andrew

--

Andrew Dunstan https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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