Re: Finding bottleneck

From: "Merlin Moncure" <merlin(dot)moncure(at)rcsonline(dot)com>
To: "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Finding bottleneck
Date: 2005-08-22 13:15:10
Message-ID: 6EE64EF3AB31D5448D0007DD34EEB3417DD15D@Herge.rcsinc.local
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

> Bill of Materials Traversal ( ~ 62k records).
>
> ISAM* pg 8.0 pg 8.1 devel delta 8.0->8.1
> running time 63 sec 90 secs 71 secs 21%
> cpu load 17% 45% 32% 29%
> loadsecs** 10.71 40.5 22.72 44%
> recs/sec 984 688 873
> recs/loadsec 5882 1530 2728
>
> *ISAM is an anonymous commercial ISAM library in an optimized server
> architecture (pg smokes the non-optimized flat file version).
> **Loadsecs being seconds of CPU at 100% load.

One thing that might interest you is that the penalty in 8.1 for
stats_command_string=true in this type of access pattern is very high: I
was experimenting to see if the new cpu efficiency gave me enough of a
budget to start using this. This more than doubled the cpu load to
around 70% with a runtime of 82 seconds. This is actually worse than
8.0 :(.

This *might* be a somewhat win32 specific issue. I've had issues with
the stats collector before. Anyways, the feature is a frill so it's not
a big deal.

Merlin

Responses

Browse pgsql-performance by date

  From Date Subject
Next Message Jignesh Shah 2005-08-22 13:47:38 MemoryContextSwitchTo during table scan?
Previous Message Mark Cotner 2005-08-22 09:29:12 Re: sustained update load of 1-2k/sec