From: Joshua D. Drake <jd@commandprompt.com>
To: Vincenzo Romano <vincenzo.romano@notorand.it>
Cc: pgsql-hackers@postgresql.org
Subject: Re: On Scalability
Date: Thu, 29 Jul 2010 10:12:06 -0700
Message-ID: <1280423526.8613.36.camel@jd-desktop.unknown.charter.com> (raw)
In-Reply-To: <AANLkTi=6=WRpND-MXv92D-+iC9AnYDwLsbbXMXj4uNky@mail.gmail.com>
References: <AANLkTi=6=WRpND-MXv92D-+iC9AnYDwLsbbXMXj4uNky@mail.gmail.com>
On Thu, 2010-07-29 at 19:08 +0200, Vincenzo Romano wrote:
> Hi all.
> I'm wondering about PGSQL scalability.
> In particular I have two main topics in my mind:
>
> 1. What'd be the behavior of the query planner in the case I have
> a single huge table with hundreds or thousands of partial indexes
> (just differing by the WHERE clause).
> This is an idea of mine to make index-partitioning instead of
> table-partitioning.
Well the planner is not going to care about the partial indexes that
don't match the where clause but what you are suggesting is going to
make writes and maintenance extremely expensive. It will also increase
planning time as the optimizer at a minimum has to discard the use of
those indexes.
>
> 2. What'd be the behavior of the query planner in the case I have
> hundreds or thousands of child tables, possibly in a multilevel hierarchy
> (let's say, partitioning by year, month and company).
Again, test it. Generally speaking the number of child tables directly
correlates to planning time. Most experience that 60-100 tables is
really the highest you can go.
It all depends on actual implementation and business requirements
however.
Sincerely,
Joshua D. Drake
--
PostgreSQL.org Major Contributor
Command Prompt, Inc: http://www.commandprompt.com/ - 509.416.6579
Consulting, Training, Support, Custom Development, Engineering
http://twitter.com/cmdpromptinc | http://identi.ca/commandprompt
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: jd@commandprompt.com, vincenzo.romano@notorand.it, pgsql-hackers@postgresql.org
Subject: Re: On Scalability
In-Reply-To: <1280423526.8613.36.camel@jd-desktop.unknown.charter.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