Asynchronous Parser

Configure additional Executor threads to parse commands from Replication Agent to reduce the time Replication Agent waits for the Executor.

With a single associated Executor thread, Replication Agent must wait for the thread to complete parsing of the LTL commands before Replication Agent can transfer the next batch commands to Replication Server. If you configure multiple threads dedicated to parsing the LTL commands, Replication Server assigns separate parsing tasks to the dedicated asynchronous parser threads resulting in the parsing of several packets of LTL commands in parallel. In addition, replication throughput improves because the Replication Agent reduces the time it must wait for the Executor thread since the transfer and parsing of data is asynchronous with multiple threads.

Ensure that smp_enable is on, and that the Replication Server host machine can support additional threads for the parsing before you configure the asynchronous parser feature. To use the asynchronous parser feature, set exec_prs_num_threads with alter connection to start multiple parser threads for a specific connection from the primary database and to specifiy the number of asynchronous parser threads for the connection. Replication Server restarts the Replication Agent when you set exec_prs_num_threads. The maximum number of threads you can start is 20. Set to 0 to disable the asynchronous parser. The minimum and default value is 0. In addition to the asynchronous parser threads, Replication Server starts a command batch synchronization thread.

Setting exec_prs_num_threads fails and Replication Server shuts down if the total number of:

Threads you want to start is greater than the number of threads available in the pool that you have specified with num_threads
Message queues to be created exceeds the number to message queues available in the pool that you have specified with num_msg_queues

Example

To start four parser threads for the connection to the pdb1 primary database in the TOKYO_DS data server:

alter connection to TOKYO_DS.pdb1
set exec_prs_num_threads to 4
go

Check for Asynchronous Parser Threads

Use admin who to display the number of Asynchronous Parser Threads that are present if exec_prs_num_threads is set to a value greater than 0. In addition, admin who shows that a Command Batch Synchronization thread is also present.