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: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] 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 ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster ---------------------------(end of broadcast)--------------------------- TIP 2: Don't 'kill -9' the postmaster
