On Freitag 03 April 2009 Wallace Tan wrote: > select count(1) from t1; That would have been my next question. I've spoken once to Paul, because dbmail uses lots of count(*), but PostgreSQL optimizes this out. Now it seems MySQL would have a performance boost using count(1).
Could you please try: 1) first, SELECT COUNT(1) FROM dbmail_messageblks; and afterwards 2) SELECT COUNT(*) FROM dbmail_messageblks; The order is important: After the first select(), the table will be cached, so the 2nd query will be faster. That, BTW, is part of the explanation why your 2nd query was much faster than the 1st. Still, count(1) should be faster than count(*) I would expect from the thread you posted. I do not have a MySQL db with enough data to test around. We're using PostgreSQL because things like that happen to exist in MySQL since years, and I don't need a DBMS where I have to think for it. I wonder why the devs don't manage to work around those problems. But no flames please, everybody should use what they prefer. mfg zmi -- // Michael Monnerie, Ing.BSc ----- http://it-management.at // Tel: 0660 / 415 65 31 .network.your.ideas. // PGP Key: "curl -s http://zmi.at/zmi.asc | gpg --import" // Fingerprint: AC19 F9D5 36ED CD8A EF38 500E CE14 91F7 1C12 09B4 // Keyserver: wwwkeys.eu.pgp.net Key-ID: 1C1209B4 _______________________________________________ DBmail mailing list DBmail@dbmail.org http://mailman.fastxs.nl/cgi-bin/mailman/listinfo/dbmail
