• PostgreSQL
  • Query optimization

PostgreSQL

Query optimization

• need to write query in certain ways sometimes, cannot rely on Postgres being smart
• source of truth: replace placeholders w/ real value, prepend EXPLAIN, run, see query plan
  • given query + plan to LLM, ask to optimize

avoid join after getting max per group:

SELECT DISCINT ON (group_key) group_key, other_columns
FROM table_name
ORDER BY group_key, column_sorted_on DESC