Stupid performance question

Hi all,

I am just wondering:
- When considering performance of a database; what matters will be the complexity of each query and the amount of related entities when doing joins, right? And wether the actual entity is a VARCHAR or a TEXT class element does not mean anything for the performance of the query?

I am only asking because some guy told me he had to change the data type for the textbody field of an email database (like for a forum application) from TEXT to VARCHAR because of the complex joins he was making. Does this all make sense? I mean; when all fields are indexed, what will the data type matter?


Hope somebody can be interested in DevShedding some light on this issue for a humble mortal!

Best regards;

avrfreak

It may be database dependent. IIRC, mysql does (used to?) have varying performance with text and varchar types. Postgres does not. Things may have changed, but this newsgroup posting reflects this:

http://groups.google.com/groups?q=m...sinki.fi&rnum=2

HTH,
-b

The only reason to use varchar over text (in Postgres anyway) is if you want to limit the max size. Otherwise they perform identically.

Thought so.

Thanks, guys!

AF