THE DANGERS OF POSTGRES SUBTRANSACTIONS

Summary from the TLDR Dev newsletter

Accumulating excessive subtransaction IDs in PostgreSQL can lead to performance issues across the cluster, affecting throughput and preventing new read replicas from accepting connections due to overflowed running transaction states. To mitigate these risks, it is recommended to keep transactions short and monitor subtransaction cache and activity, while potential solutions on the PostgreSQL side could involve increasing the cache size or implementing a new snapshot methodology.