Postgres "Canceling Statement Due to Statement Timeout" Fix
"Canceling statement due to statement timeout" means a configured statement_timeout deliberately killed a query that ran longer than allowed — the right fix...
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All troubleshooting articles, newest first.
Postgres "FATAL: Remaining Connection Slots Are Reserved for Non-Replication Superuser Connections"
This specific error means PostgreSQL has hit its max_connections limit for regular users, but is deliberately still reserving a small number of slots...
Postgres "Invalid Byte Sequence for Encoding UTF8" on Data Import
This error means the data you're importing contains byte sequences that aren't valid UTF-8 — Postgres, when configured with UTF-8 encoding (the common,...
PostgreSQL "Canceling Autovacuum Task Due to Lock Conflict"
This message means autovacuum backed off from a table because another session needed a conflicting lock — this is largely normal, expected behavior (autovacuum...
PostgreSQL Constraint CHECK Failing on NULL Values, Unexpected Behavior
A CHECK constraint that seems to allow a NULL value through, despite the constraint's condition apparently not being satisfied by NULL, is actually correct,...
PostgreSQL "Prepared Statement Does Not Exist" Error in Connection Poolers (PgBouncer)
"Prepared statement does not exist" specifically under PgBouncer almost always comes down to a fundamental incompatibility between how prepared statements work...
PostgreSQL Query Slow After Bulk Insert (VACUUM ANALYZE Required)
A query that was fast before a large bulk insert but becomes slow immediately afterward almost always means PostgreSQL's query planner is working from outdated...
Postgres Slow Subquery Performance: Replacing IN With EXISTS or JOIN
A slow query using a subquery inside IN can often be sped up significantly by rewriting it as EXISTS or a JOIN — while modern Postgres's planner is often smart...
Nginx 500 Internal Server Error Without Any Error Log Output
A 500 error with nothing showing up in Nginx's error log doesn't mean Nginx has no idea what happened — it usually means either the log level is set too...