Finding the database indexes
One aspect of writing well-performing queries is using the database optimization properties. When working in row-oriented databases, you want to limit the number of records returned. If partitions and indexes exist, you should use them in your queries as filters. Ideally, you could reference a database diagram or ask your friendly database administrator (DBA) which tables and columns have indexes.
However, sometimes documentation is missing, and DBAs are busy. Luckily, the pg_tables schema has views that show all the existing indexes.
Cet exercice fait partie du cours
Improving Query Performance in PostgreSQL
Instructions
- Choose metadata from the
pg_indexesview. - Select
tablenameandindexnameto see the indexes in each table.
Exercice interactif pratique
Essayez cet exercice en complétant cet exemple de code.
SELECT ___
, ___
FROM ___;