Re: More grist for the PostgreSQL vs MySQL mill

From: Chris <dmagick(at)gmail(dot)com>
To: Shashank Tripathi <shashank(dot)tripathi(at)gmail(dot)com>
Cc: pgsql-general(at)postgresql(dot)org
Subject: Re: More grist for the PostgreSQL vs MySQL mill
Date: 2007-01-22 03:17:20
Message-ID: 45B42CC0.70402@gmail.com
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Shashank Tripathi wrote:
>> select something from othertable;
>> select * from table where table_id in (?, ?, ?, ?, ?, ?, ?, ...)
>
>
> This is what MySQL's CEO Martin said in an interview on Slashdot. If
> we can manage two queries as above through, say, a PHP application,
> with each executing in 0.004 seconds, then an optimized subquery needs
> to be beat the 0.008 mark to be a viable alternative.

Not really.

If you have too many values, you have problems.. eg the "select
something from table" returns 100+ records (for example, don't have a
concrete number), you'll run into this problem:

http://dev.mysql.com/doc/refman/4.1/en/packet-too-large.html

when you try to put them all in the 'in' clause in the 2nd query.

But as you say not usually a problem in most cases but something you
need to be aware of (and you're only aware of it once you've been bitten
by it heh).

--
Postgresql & php tutorials
http://www.designmagick.com/

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