2010/5/26 Maria L. Wilson
<Maria.L.Wilson-1@nasa.gov> Was hoping that someone would like to discuss the need for indexes on columns that are referenced in a foreign key. Are they necessary? Are they worth the overhead? PostgreSQL version 8.4
That depends. They are not necessary. They are overhead (like all other indexes). They can be useful, or not be useful. Can be used or not.
All depends mainly on your queries and how many records you have. If you have enough, the index can be really helpful (of course that depends on the query that you make).
regards
Szymon Guz