Tips on how to debug Postgres:

• Explain Analyze
• Slow Statements
• Session Activity

Explain Analyze

Check if the planner chose a bad plan for your query:

EXPLAIN (ANALYZE, BUFFERS)
SELECT ...

EXPLAIN ANALYZE runs the statement and shows actual timings and BUFFERS helps identify heavy reads/hits.

Slow Statements

Find slow statements:

SELECT
  query,
  calls,
  total_exec_time,
  mean_exec_time,
  rows
FROM pg_stat_statements
ORDER BY total_exec_time DESC
LIMIT 20;

Depending on the queries, you can improve the query-plan, index, and/or infrastructure.

Session Activity

Check what sessions are waiting on:

SELECT
  pid,
  usename,
  state,
  wait_event_type,
  wait_event,
  query
FROM pg_stat_activity
WHERE state <> 'idle';

• Lock (for wait_event_type) means there’s a blocking/locking problem.
• IO or buffer-related waits means there’s a storage/cache issue.
• Little waiting time but high runtime means there could be an expensive execution plan or CPU-heavy work.