On Tue, Nov 05, 2002 at 07:14:25PM -0600, D. Walton wrote: > > I have a table with 3 fields, 'id', 'date', and 'value'. I've created a > unique index on 'id' and 'date' in order to lookup 'value' quickly. I > would like to be able to add 'value' to the index so that the data files > does not have to be referenced and will allow faster lookups and groupings > by date, however, I can't lose the ability to do "insert ignore" on the > 'id' and 'date' unique index. So the question is, if I create a primary > key of 'id', 'date', 'value', and then create a secondary unique index of > 'id' and 'date' will MySQL simply reuse the primary key for the secondary > unique index or will it create a totally separate index on the disk?
It will create a totally separate index, since that's what you told it to do. :-) > If it creates a totally separate index then it will just have to > update two indexes for every insert which in the end will slow > things down. Yes. It's a design tradeoff you need to consider. Jeremy -- Jeremy D. Zawodny | Perl, Web, MySQL, Linux Magazine, Yahoo! <[EMAIL PROTECTED]> | http://jeremy.zawodny.com/ MySQL 3.23.51: up 91 days, processed 1,905,923,218 queries (240/sec. avg) --------------------------------------------------------------------- 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
