Replicating transactions in batches

Effects of buffering transactions

The LTM allows buffering of replication commands to Replication Server. Buffering the replication commands and sending them in batches results in fewer messages being sent, and can significantly increase overall throughput, especially on high volume installations.

How batch mode works

By default, the LTM buffers transactions. The buffer flushes the transactions sent to Replication Server when the buffer:

  • Reaches maximum number of commands   The batch_ltl_sz parameter sets the maximum number of LTL (log transfer language) commands stored in the buffer before it flushes. The default setting is 200.

  • Reaches maximum memory used   The batch_ltl_mem parameter sets the maximum memory that the buffer can occupy before flushes. The default setting is 256 KB.

  • Completes transaction log processing   If there are no more entries in the transaction log to process (that is, the LTM is up to date with all committed transactions), then the buffer flushes.

Turning off buffering

You can turn off buffering of transactions by setting the batch_ltl_cmds parameter to off:

batch_ltl_cmds=off