On Tuesday 16 July 2002 05:05 pm, Jeremy Zawodny wrote: > On Tue, Jul 16, 2002 at 03:52:35PM -0400, walt wrote: > > I have an INNODB table which has 99994 records in it. customer_number is > > the primary key. > > > > If I run > > select count(cutomer_number) from customer; > > > > It takes about 15 seconds to return the number of rows. > > I ran explain on the query and it's using the unique key index on > > customer_number. > > That's documented. InnoDB must read the whole table. > > > If I run > > SHOW TABLE STATUS LIKE 'cutomer'; > > it only takes about 1.52 seconds for innodb to tell me number of rows. > > That's an estimate of the number of rows. > > Jeremy
Thanks Jeremy! After I sent this email, I changed the primary key to a unique index and it took under 2 seconds to return the number of rows. Do you know of any advantage a primary key would have over a unique index? The unique index still enforces the uniqueness of the column. Kinda funny that the error message from violating the unique index is "Duplicate entry '104191' for key 1" :-) Thanks! -- Walter Anthony System Administrator National Electronic Attachment Atlanta, Georgia 1-800-782-5150 ext. 1608 "If it's not broke....tweak it" --------------------------------------------------------------------- Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail <[EMAIL PROTECTED]> To unsubscribe, e-mail <[EMAIL PROTECTED]> Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
