Tuning a slow query

Rewriting is often better than indexing. Remove the function on the indexed column, cut the rows early, and check the plan again.

What this lesson covers

• Rewrite predicates so an index can be used
• Reduce the row count as early as possible
• Verify the improvement with a fresh plan

This lesson sits in Query Performance, part of PostgreSQL for Developers. It assumes what came before it and leads directly into the next lesson in the module.