Exercise 4: Resolve PostgreSQL Transaction Abort in Batch Consumer

[harsharajkumar-273]

Goal

Ensure resilient database batch updates when message failures occur.

Problem

In src/consumer.ts, when processing a batch of events inside a PostgreSQL transaction (BEGIN ... COMMIT), if a single metric write fails due to constraint violations or database issues, PostgreSQL marks the active transaction as aborted. The loop keeps trying to issue queries on the aborted client, the final COMMIT fails, and the worker loops indefinitely re-consuming the exact same batch.

Task

1. Resolve the aborted transaction block issue in the consumer batch loop.
2. You can rewrite the writes as a single bulk INSERT query (using dynamic values) with ON CONFLICT DO NOTHING to avoid individual line failures.
3. Alternatively, utilize SQL SAVEPOINT sub-transactions to isolate individual insert errors.