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Re^2: Does DBI handle table alias?

by The_Rabbit (Acolyte)
on Oct 06, 2004 at 21:10 UTC ( #397165=note: print w/replies, xml ) Need Help??

in reply to Re: Does DBI handle table alias?
in thread Does DBI handle table alias?

Be careful... you really don't want to create anymore indexes than necessary. Even though you might see a performance increase in your test by building a bunch of extra indexes you might end up causing performance problems in other parts of the system. Remember, that whenever a rows are inserted or deleted there is an additional work that has to be for each index. Just like everything else in programming you have to strike a balance.

Looking at the query you had problems with I am guessing that the only indexes that are going to help are to build an index for user_id and characteristic_id for both tables. Generally, columns that appear in join conditions are good candidates for building an index.

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