Big Problems From Big IN lists with Ruby on Rails and PostgreSQL
a year ago
- #Active Record
- #PostgreSQL
- #database performance
- Big IN clauses with large lists of values can cause performance issues in relational databases.
- Active Record ORM methods like `includes` and `preload` can implicitly generate IN clause queries.
- Alternatives to IN clauses include using ANY or SOME operators, VALUES clauses, or restructuring queries to use joins.
- PostgreSQL 17 and 18 introduce improvements for handling IN clauses and grouping similar queries in pg_stat_statements.
- Testing query performance with EXPLAIN (ANALYZE, BUFFERS) is recommended to identify and optimize problematic queries.