| From: | Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com> |
|---|---|
| To: | Jamie Koceniak <jkoceniak(at)mediamath(dot)com> |
| Cc: | "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Recursive query performance issue |
| Date: | 2015-10-21 07:03:37 |
| Message-ID: | CAFj8pRB5fmPqc4DZyWwJqkdMM8OhnZJBivxuf46hR5UYEQfi6Q@mail.gmail.com |
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| Lists: | pgsql-performance |
Hi
2015-10-20 19:34 GMT+02:00 Jamie Koceniak <jkoceniak(at)mediamath(dot)com>:
> Version:
>
>
> -----------------------------------------------------------------------------------------------
>
> PostgreSQL 9.1.14 on x86_64-unknown-linux-gnu, compiled by gcc (Debian
> 4.7.2-5) 4.7.2, 64-bit
>
>
>
> Query Plan
>
> http://explain.depesz.com/s/4s37
>
>
>
> Normally, this query takes around 200-300 ms to execute.
>
> However when several queries are run concurrently, query performance drops
> to 30-60 seconds.
>
>
>
there can be few reasons:
1. locking - are you sure, so your queries don't wait on locks?
2. issues with cache stability - is there high IO load? You can try to
increase effective_cache_size (or decrease if you have not enough memory)
Regards
Pavel
>
>
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