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Re: Vacuum Verbose output

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Scott Marlowe <smarlowe(at)g2switchworks(dot)com>
Cc: "Tomeh, Husam" <htomeh(at)firstam(dot)com>, pgsql-admin(at)postgresql(dot)org
Subject: Re: Vacuum Verbose output
Date: 2005-11-01 03:59:13
Message-ID: 21438.1130817553@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-admin
Scott Marlowe <smarlowe(at)g2switchworks(dot)com> writes:
> On Mon, 2005-10-31 at 16:34, Tomeh, Husam wrote:
>> Pre-allocating space will prevent extending the datafile during
>> loading massive data (batch processing) and would improve the overall
>> batch write performance. 

> Have you got any file system benchmarks that back up this assertion?  I 
> would love to see something that shows one way or the other if that
> really makes any difference.

Barring some pretty solid evidence, you're unlikely to attract any
enthusiasm among pghackers for this sort of thing.  We are generally
disinclined to reinvent functionality that properly belongs to the
kernel or filesystem layer.  "Oracle does it" cuts no ice in this
connection, because Oracle is designed around a twenty-year-old
assumption that the database is smarter than the kernel, and the world
has changed a lot since then.

In short: show us some numbers that prove this is worth our attention.

			regards, tom lane

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