T[RANSACTIONID]=expr

The TRANSACTIONID keyword declares an arbitrary transaction identification.

If TRANSACTIONID="BATCH" or "BA" at transaction completion, the process immediately continues execution. When a process issues a [final] TCOMMIT for a transaction and journaling is active, by default the process waits until the entire transaction is written to the journal file(s) before executing the next command. This ensures that every transaction is durable before the process moves on to the next step.

Transactions flagged as "BATCH" have lower latency and higher throughput, but a lower guarantee of durability. Normally this flag is used when operational procedures (such as a backup) or application code (such as a checkpoint algorithm) provides an acceptable alternative means of ensuring durability.