statement completion unknown
Production Risk
Critical: potential for duplicate writes if the statement committed and is retried without verifying state.
SQLSTATE 40003 is raised when a statement completes but it is not known whether the statement succeeded or failed — typically because the connection broke at the point of command completion. This is a rare but critical production risk.
- 1The connection breaks immediately after a statement executes but before the server can confirm the result to the client
Connection failure at statement completion.
expected output
ERROR: statement completion unknown
Fix 1
Query the database to verify whether the statement had an effect
WHEN After receiving 40003.
Why this works
Reconnect and query for business-observable evidence of the statement. If the effect is present, do not retry. If absent, retry is safe.
Fix 2
Use idempotent operations to allow safe retries
WHEN When designing systems that must tolerate uncertain statement completion.
INSERT INTO orders (id, ...) VALUES (:client_uuid, ...) ON CONFLICT (id) DO NOTHING;
Why this works
Idempotent inserts with a client-generated primary key allow safe retries regardless of whether the original statement committed.
✕ Retry blindly after 40003
If the original statement committed, a retry causes duplicate data.
Class 40 — Transaction Rollback
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