You hit the nail on the head with what we did. We did two things and it
made a world of difference.
We moved from RAID 5 SCSII drives to our EMC SAN RAID 10 and adjusted
the checkpoint segments from 15 to 30.
The bottleneck disappeared totally and actually have never seen better
What are the implications to further increasing the checkpoint so say
Also how does 8.0's background-writer feature work and what are going to
From: Tom Lane [mailto:tgl(at)sss(dot)pgh(dot)pa(dot)us]
Sent: Tuesday, October 26, 2004 5:59 PM
To: Brian Maguire
Subject: Re: [GENERAL] what could cause inserts getting queued up and db
Brian Maguire <bmaguire(at)vantage(dot)com> wrote:
>> We though there might be locking, but noticed that there were not any
>> queries in wait mode indicating that no statements were blocked by
>> another statement's lock.
In that case it's not a locking problem, but just a resource-saturation
problem. I'm wondering if you are maxing out your disk drives'
Are the slowdowns correlated with checkpoints? (Watch to see if there
is a postmaster child process spawned for checkpointing when it
happens.) Fooling with checkpoint intervals might help some, though
I suspect the only real answer will be 8.0's background-writer feature.
regards, tom lane
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