Heh, sorry, was too vague in my original post.
:S
quote:
Unless you mean the storage methods for indexes. Which can be HASH (only available to MEMORY / HEAP tables), BTREE or RTREE, but they're just the file format that the index is stored in. Never bothered to find out if there is any advantage of using one over the other.
That's the bit I'm after.
I know there are differences, but not how significant they are.
I think HASH is better for direct lookups (eg: find nickname from uid), and in general has less insert/update overhead than BTREE, however BTREE is self-organising, whereas a HEAP/HASH needs to be regularly optimized else performance goes down the pan.
I don't even know if that is properly accurate - I think I may be mixing up stuff about table types.
:S
During my searches I found a PostgreSQL page saying that the pgSQL implementation of HASH is shit and everyone should always use BTREE. No idea if that applies to MySQL or not.
EDITED: 25 May 2008 23:45 by BOUGHTONP