| From: | Waldo Nell <pwnell(at)telkomsa(dot)net> |
|---|---|
| To: | pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Recommended optimisations slows down PostgreSQL 8.4 |
| Date: | 2011-08-12 00:27:14 |
| Message-ID: | FE19EF2B-56BF-4DB1-9459-4DEA8D56B8BF@telkomsa.net |
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| Lists: | pgsql-performance |
On 2011-08-11, at 17:18 , ktm(at)rice(dot)edu wrote:
> One guess is that you are using the defaults for other costing parameters and they
> do not accurately reflect your system. This means that it will be a crap shoot as
> to whether a plan is faster or slower and what will affect the timing.
Ok, but I thought the way to best optimise PostgreSQL is to start with the parameters having the biggest impact and work from there. To adjust multiple parameters would not give a clear indication as to the benefit of each, as they may cancel each other out.
To test your theory, what other parameters should I be looking at? Here are some more with their current values:
random_page_cost = 4.0
effective_cache_size = 128MB
Remember this runs on SATA so random seeks are not as fast as say SSD.
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