From: | Miroslav Šulc <miroslav(dot)sulc(at)startnet(dot)cz> |
---|---|
To: | John Arbash Meinel <john(at)arbash-meinel(dot)com> |
Cc: | PGSQL mailing list <pgsql-performance(at)postgresql(dot)org> |
Subject: | Re: How to read query plan |
Date: | 2005-03-14 08:58:49 |
Message-ID: | 42355249.8090101@startnet.cz |
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Lists: | pgsql-hackers pgsql-performance |
John Arbash Meinel wrote:
>> In fact, on MySQL I didn't see any slow reactions so I didn't measure
>> and inspect it. But I can try it if I figure out how to copy the
>> database from PostgreSQL to MySQL.
>
>
> I figured you still had a copy of the MySQL around to compare to. You
> probably don't need to spend too much time on it yet.
So I have some results. I have tested the query on both PostgreSQL 8.0.1
and MySQL 4.1.8 with LIMIT set to 30 and OFFSET set to 6000. PostgreSQL
result is 11,667.916 ms, MySQL result is 448.4 ms.
Both databases are running on the same machine (my laptop) and contain
the same data. However there are some differences in the data table
definitions:
1) in PostgreSQL I use 'varchar(1)' for a lot of fields and in MySQL I
use 'enum'
2) in PostgreSQL in some cases I use connection fields that are not of
the same type (smallint <-> integer (SERIAL)), in MySQL I use the same types
>
> John
> =:->
Miroslav
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