feat(posts): add "PostgreSQL Debug Tips"

Post: 2026-03-23-postgresql-debug-tips.md

Author: remarkablemark

_posts/2026/2026-03-23-postgresql-debug-tips.md

@@ -0,0 +1,62 @@
+---
+layout: post
+title: PostgreSQL Debug Tips
+date: 2026-03-23 17:15:04
+excerpt: Tips on how to debug PostgreSQL database.
+categories: postgresql debug database
+---
+
+Tips on how to debug Postgres:
+
+- [Explain Analyze](#explain-analyze)
+- [Slow Statements](#slow-statements)
+- [Session Activity](#session-activity)
+
+## Explain Analyze
+
+Check if the planner chose a bad plan for your query:
+
+```sql
+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:
+
+```sql
+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:
+
+```sql
+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.