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Re: problems with new vacuum (??)

From: "Matthew T(dot) O'Connor" <matthew(at)zeut(dot)net>
To: Barry Lind <barry(at)xythos(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-hackers(at)postgresql(dot)org
Subject: Re: problems with new vacuum (??)
Date: 2002-01-02 14:49:58
Message-ID: 200201021442.g02EgZZ25397@neuromancer.ctlno.com (view raw or flat)
Thread:
Lists: pgsql-hackers
On Tuesday 01 January 2002 11:23 pm, Barry Lind wrote:
> Tom,
>
> The platform is Redhat 7.0 with a 2.2.19 kernal.

Is this and IDE based system?  If so do you have the drives running in DMA 
mode?

What are the results of "/sbin/hdparm /dev/hd(?)" (a,b,c,d ... which ever 
drive you are running the database on.)

The 2.2 linux kernel defaults to DMA off.  You can try to enable dma by 
issuing /sbin/hdparm -d1 /dev/hd(?)  You can also test the disk speed with 
/sbin/hdparm -tT /dev/hd(?).

In my experience enabling this feature can make a huge improvement in I/O 
intensive applications.  Other options can help also, but I find dma to have 
the largest impact.  I find linux almost unusable without it.

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Subject: Re: problems with new vacuum (??)
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