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Date: Thu, 19 Mar 2009 19:28:19 -0400
From: "Jignesh K. Shah" <J.K.Shah@Sun.COM>
Subject: Re: Postgres benchmarking with pgbench
In-reply-to: <49C2B854.4080303@bortal.de>
To: "ml@bortal.de" <ml@bortal.de>
Cc: Greg Smith <gsmith@gregsmith.com>, pgsql-performance@postgresql.org
Message-id: <49C2D513.6090002@sun.com>
References: <49BE2E84.2040506@bortal.de>
	<alpine.GSO.2.01.0903161052430.9846@westnet.com>
	<49C2B854.4080303@bortal.de>
User-Agent: Thunderbird 2.0.0.19 (Windows/20081209)


ml@bortal.de wrote:
> Hi Greg,
>
> thanks a lot for your hints. I changed my config and changed raid6 to 
> raid10, but whatever i do, the benchmark breaks down at a scaling 
> factor 75 where the database is "only" 1126MB big.
>
> Here are my benchmark Results (scaling factor, DB size in MB, TPS) using:
>   pgbench -S -c  X  -t 1000 -U pgsql -d benchmark -h MYHOST
>
> 1 19 8600
> 5 79 8743
> 10 154 8774
> 20 303 8479
> 30 453 8775
> 40 602 8093
> 50 752 6334
> 75 1126 3881
> 150 2247 2297
> 200 2994 701
> 250 3742 656
> 300 4489 596
> 400 5984 552
> 500 7479 513
>
> I have no idea if this is any good for a QuardCore Intel(R) Xeon(R) 
> CPU  E5320  @ 1.86GHz with 4GB Ram and 6 SATA disk (7200rpm) in raid 10.
>
> Here is my config (maybe with some odd setting): 
> http://pastebin.com/m5d7f5717
>
> I played around with:
> - max_connections
> - shared_buffers
> - work_mem
> - maintenance_work_mem
> - checkpoint_segments
> - effective_cache_size
>
> ..but whatever i do, the graph looks the same. Any hints or tips what 
> my config should look like? Or are these results even okay? Maybe i am 
> driving myself crazy for nothing?
>
Are you running the pgbench client from a different system? Did you 
check if the pgbench client itself is bottlenecked or not. I have seen 
before the client of pgbench is severely limited on the load it can 
drive and process.


-Jignesh