What makes a index good

1. will the query planner pick that index?
   • To be used, the query planner has to figure that this index you defined serves the query at hand. If it doesn't, the index is just dead weight.
   • An index would be evaluated on applicability to the query and on its quality

Applicability is whether the index matches up the query filter criteria at will.

Index Considerations

• Speeds-up Queries
• Minimize Index Size
• Minimize index count
• Maximize Selectivity

Over Indexing vs Under Indexing