Re: Tsearch2 Initial Search Speed

From: Howard Cole <howardnews(at)selestial(dot)com>
To: pgsql-performance(at)postgresql(dot)org
Subject: Re: Tsearch2 Initial Search Speed
Date: 2008-06-17 09:54:09
Message-ID: 485789C1.3000803@selestial.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

Alan Hodgson wrote:
> It's because everything is cached, in particular the relevant rows from
> the "email" table (accessing which took 22 of the original 27 seconds).
>
> The plan looks good for what it's doing.
>
> I don't see that query getting much faster unless you could add a lot more
> cache RAM; 30K random IOs off disk is going to take a fair bit of time
> regardless of what you do.
>
>

Thanks Alan, I guessed that the caching was the difference, but I do not
understand why there is a heap scan on the email table? The query seems
to use the email_fts_index correctly, which only takes 6 seconds, why
does it then need to scan the email table?

Sorry If I sound a bit stupid - I am not very experienced with the
analyse statement.

In response to

Responses

Browse pgsql-performance by date

  From Date Subject
Next Message Howard Cole 2008-06-17 10:54:12 Re: Tsearch2 Initial Search Speed
Previous Message Chris Mair 2008-06-16 19:26:14 Re: [pgsql-performance] function difference(geometry, geometry) is SLOW!