Postgresql uses MVCC to ensure data integrity. Server must choose the right
version of tuple, according to transaction ID of statement. Even for a
select (ACID features of postgresql, I think C and I apply here), it must
accomplish some extra work.
-----Mensaje original-----
De: pgsql-performance-owner@postgresql.org
[mailto:pgsql-performance-owner@postgresql.org]En nombre de Joe
Enviado el: martes, 04 de octubre de 2005 18:11
Para: Jim C. Nasby
CC: Andreas Pflug; pgsql-performance@postgresql.org
Asunto: Re: [PERFORM] Comparative performance
Hi Jim,
Jim C. Nasby wrote:
> Also, just because no one else has mentioned it, remember that it's very
> easy to get MySQL into a mode where you have no data integrity. If
> that's the case it's going to be faster than PostgreSQL (though I'm not
> sure how much that affects the performance of SELECTs).
Yes indeed. When I added the REFERENCES to the schema and reran the
conversion
scripts, aside from having to reorder the table creation and loading (they
used
to be in alphabetical order), I also found a few referential integrity
errors in
the MySQL data.
Joe
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