tableA, definition: key1 char(17) not null,
acct char(12),
other char (5)tableB is same definiton like tableA.
I add index for both tableA and tableB like: alter table tableA add index(key1, acct)
I will do left join with tableA and tableB like : tableA left join on tableB on tableA.acct=tableB.acct where.... tableB left join on tableA on tableB.acct=tableA.acct where....
The tableA has 32,000,000 records and tableB has 500,00 records.
I feel some thing wrong about how define the table fields, add index or something, because I only use acct field for left join on.
I hope I can change some table definition or about add index to improve the performance.
Also, I like to know what is difference between:
alter table tableA add index(key1, acct)
or alter table tableA add index(key1) alter table tableA add index(acct)
Any suggestion? Thanks.
--------------------------------------------------------------------- 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
