Elevarq Blog
Technical writing on PostgreSQL performance, database operations, observability, and the engineering systems behind our products.
"does not exist" in PostgreSQL: how to read the error and stop guessing
9:14 Tuesday morning. The deploy hit production and the user-lookup endpoint returns 500s with 'operator does not exist: text = uuid'. The column exists, the parameter is bound, the rollback is being drafted. PostgreSQL's resolver is telling you exactly what went wrong — almost nobody reads past the first line. How to read the message, and the five levers (cast, signature, schema, extension, quoting) that fix the family.
Inheriting a Postgres database
You inherited the database six months ago. Today the BI engineer needs SELECT on the analytics schema by 2pm — but the table the ETL created last week returns permission denied. A walk through the small PostgreSQL commands every team rediscovers under pressure, and the pattern that makes them compound when they all hit at once: ALTER DEFAULT PRIVILEGES, pg_dump shapes, SHOW, numeric types, psql meta-commands, and the seams of running on RDS.
Why your PostgreSQL planner is wrong (and what to do about it)
The planner estimates costs for every query plan. When those estimates are wrong, performance degrades. Here is how to find and fix planner misestimation.