What tools in PostgreSQL can be used to determine which query runs slower than others?

In PostgreSQL, several tools can be used to identify slow queries:

1. pg_stat_statements — an extension that collects statistics on executed queries, including average execution time. It helps identify the "heaviest" queries.

2. Logging slow queries — in the PostgreSQL configuration, you can enable the log_min_duration_statement parameter, specifying a time threshold (in milliseconds). All queries running longer than this threshold will be logged.

3. EXPLAIN ANALYZE — provides a detailed execution plan for a specific query with actual timing at each step.

4. pgBadger — a tool for analyzing PostgreSQL logs, helping visualize and find slow queries.

Example of enabling slow query logging in postgresql.conf:

log_min_duration_statement = 500  # log queries longer than 500 ms

Afterward, logs will contain entries about slow queries, which can be analyzed.