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Re: Crappy performance even though not swapping

From: "Neil Aggarwal" <neil(at)JAMMConsulting(dot)com>
To: <pgsql-novice(at)postgresql(dot)org>
Subject: Re: Crappy performance even though not swapping
Date: 2007-02-28 03:18:43
Message-ID: 001301c75ae7$26db7410$0501a8c0@neilhp (view raw or flat)
Thread:
Lists: pgsql-novice
Philip:

Thanks for the advice.  If you look at my next post, I figured
out the problem was an index on the table I was inserting into.

In answer to your questions:
1. I have 4 SATA drives and am using software RAID1 on them.
2. I have not increased the default RAM for the pg process,
	but that does not seem to be a problem after I removed
	the index.  Would adding more RAM to the process speed up
	the inserts even with the index on the table?

Thanks,
	Neil


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Neil Aggarwal, (214)986-3533, www.JAMMConsulting.com
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-----Original Message-----
From: pgsql-novice-owner(at)postgresql(dot)org
[mailto:pgsql-novice-owner(at)postgresql(dot)org] On Behalf Of Phillip Smith
Sent: Tuesday, February 27, 2007 9:10 PM
To: 'Neil Aggarwal'; pgsql-novice(at)postgresql(dot)org
Subject: Re: [NOVICE] Crappy performance even though not swapping

What hard drives are you running? IDE / SCSI / SATA? Are they in a hardware
/ software RAID? PG still has to commit changes to disk regardless of
swapping - there might be a bottleneck at the disk I/O for the commits.

Also, your postmaster doesn't seem to be using much RAM. Have you tweaked
the conf files to allow the pg processes to use more RAM than default?

Cheers,
~p


-----Original Message-----
From: pgsql-novice-owner(at)postgresql(dot)org
[mailto:pgsql-novice-owner(at)postgresql(dot)org] On Behalf Of Neil Aggarwal
Sent: Wednesday, 28 February 2007 13:50
To: pgsql-novice(at)postgresql(dot)org
Subject: [NOVICE] Crappy performance even though not swapping

Hello:

I have a Java program that is trying to import over 8 million 
rows from a text file.

When the program starts up, it runs fine, but after a while
it begins to crawl.

This is usually symptomatic of a machine that started swapping,
but take a look at the attached output from top.

I am using a LOT of memory, but the swap is still very 
low.  I don't think the machine should be paging to disk.

The CPU states show that the cpus are spending most of their time 
in an idle state.  The process list shows the postmaster and java 
processes are less than 10 percent the CPU cycles.

Having said that, the load average is still about 2.

Any ideas what could be going on?

Thanks,	
	Neil

--
Neil Aggarwal, (214)986-3533, www.JAMMConsulting.com
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Subject: Re: Crappy performance even though not swapping
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