Re: Rules slower than Dynamic SQL ?

From: Decibel! <decibel(at)decibel(dot)org>
To: Simon Riggs <simon(at)2ndquadrant(dot)com>
Cc: Alex Vinogradovs <AVinogradovs(at)Clearpathnet(dot)com>, pgsql-general <pgsql-general(at)postgresql(dot)org>
Subject: Re: Rules slower than Dynamic SQL ?
Date: 2007-12-06 21:49:03
Message-ID: 02A3553D-DF79-4681-BE6F-EF5B3C3FED6E@decibel.org
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On Nov 26, 2007, at 6:09 PM, Simon Riggs wrote:
> On Mon, 2007-11-26 at 16:01 -0800, Alex Vinogradovs wrote:
>> I've got a data warehouse with pretty high rate of insert into
>> partitioned tables. What I've noticed, is that rule-based
>> partitioning
>> seems to be somewhat slower than insertions made directly into
>> partitions through execution of dynamic SQL.
>>
>> Is it really true ?
>
> Depends how complex your rules are, but I think yes is the short
> answer.

My understanding is that each rule has to re-evaluate the query
that's being run. That's going to add some overhead to a simple
INSERT INTO table VALUES ... but if you think that's bad, try it with
an expensive INSERT INTO table SELECT statement!
--
Decibel!, aka Jim C. Nasby, Database Architect decibel(at)decibel(dot)org
Give your computer some brain candy! www.distributed.net Team #1828

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