From: Heikki Linnakangas <hlinnakangas@vmware.com>
To: obartunov@gmail.com, Laurence Parry <greenreaper@hotmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Workaround: Planner preference for tsquery filter vs. GIN index in fast text search
Date: Tue, 22 Apr 2014 09:28:23 +0300
Message-ID: <53560C07.80207@vmware.com> (raw)
In-Reply-To: <CAF4Au4w_th88hf9STrjATX1EW9w5xzjGXN8Mxar_E=2qc3JJcw@mail.gmail.com>
References: <BLU178-DS1116AC5CC07E7D50A4589CA55F0@phx.gbl>
<CAF4Au4w_th88hf9STrjATX1EW9w5xzjGXN8Mxar_E=2qc3JJcw@mail.gmail.com>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>
On 04/20/2014 07:46 AM, Oleg Bartunov wrote:
> btw, 9.4 should be wiser in case of rare+common terms, thanks to GIN
> fast scan feature.
Indeed, although we didn't actually do anything to the planner to make
it understand when fast scan helps. Doing something about cost
estimation is still on the 9.4 Open Items list, but I don't have any
ideas on what to do about it, and I haven't heard anything from
Alexander about that either. That means that the cost estimation issue
Laurence saw is going to be even worse in 9.4, because GIN is going to
be faster than a seq scan in more cases than before and the planner
doesn't know about it.
- Heikki
--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: hlinnakangas@vmware.com, greenreaper@hotmail.com
Subject: Re: Workaround: Planner preference for tsquery filter vs. GIN index in fast text search
In-Reply-To: <53560C07.80207@vmware.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox