Fix: AWS RDS Connection Timeout
Verify SG ingress from caller SG on the DB port
RDS connection timeouts are almost always a security group, subnet route, or a saturated connection pool on the DB.
Frequently Asked Questions
What causes AWS RDS Connection Timeout?
RDS connection timeouts are almost always a security group, subnet route, or a saturated connection pool on the DB.
How to fix AWS RDS Connection Timeout?
Confirm the Lambda's SG is allowed as a source on the RDS SG on port 5432. If allowed, check `pg_stat_activity` for connection exhaustion before adding retries.
Example fix from Kintify Fix
Input: Application Lambda can't connect to RDS Postgres
Output: Confirm the Lambda's SG is allowed as a source on the RDS SG on port 5432. If allowed, check `pg_stat_activity` for connection exhaustion before adding retries.
Used by developers debugging real production systems