Guides
Practical guides for debugging logs and PostgreSQL. Each one explains the method first; the tools are optional.
Log analysis
How to read production logs across several services
How to read production logs from several services: put them on one timeline, follow a request through them, and compare a good run with a bad one.
How to sort and filter a Graylog export
How to read a Graylog CSV export: sort the lines by time, filter them with grep, and keep stack traces together.
Log generation best practices, with a Spring Boot example
How to write logs that are easy to search later: request ids, structured fields, levels, and a Spring Boot example that sends them to Graylog.
PostgreSQL performance
PostgreSQL performance: finding the slow query
How to find the PostgreSQL query that is slowing your database: common causes, pg_stat_statements, pg_stat_activity, locks and EXPLAIN ANALYZE.
How to read a PostgreSQL EXPLAIN plan
How to read a PostgreSQL EXPLAIN ANALYZE plan: what to check first, what the node types mean, and a before and after example with real output.