Asynchronous Parser, ASCII Packing, and Direct Command Replication

Obtain improvements throughout the replication process during data transformation and transport by utilizing the asynchronous parser, ASCII packing, and inbound and outbound direct command replication features together.

Replication Server processes data in the Executor (EXEC) thread, Distributor (DIST) thread, and Data Server Interface (DSI) thread in sequence:

The EXEC thread transfers LTL commands from a Replication Agent to Replication Server.
The EXEC thread parses the LTL commands and stores them in an internal parsed format and packs the parsed data in binary format.
The EXEC thread writes the binary data through the inbound SQM thread, to the inbound queue.
The DIST module retrieves the binary commands, restores the commands to the original format, and determines where to send the commands.
Before the DIST module sends the commands to the DSI module, DIST packs the commands in an internal ASCII format and writes the commands through the outbound SQM thread, to a outbound stable queue .
Then DSI module reads and parses the ASCII commands, and restores the commands to their original format.

The asynchronous parser, and inbound and outbound direct command replication features improve replication peformance for specific steps in the sequence, while ASCII packing reduces queue storage consumption. However, you can gain maximum performance improvements and reduction in queue storage consumption by using all of these features together. Instead of configuring each of the features separately, use async_parser with alter connection to configure them at the same time.

Ensure that smp_enable on, and that the Replication Server host machine can support additional threads for the parsing before you configure the asynchronous parser feature.

Setting async_parser on sets:

Asynchronous parser on – sets exec_prs_num_threads to 2
ASCII packing on – sets ascii_pack_ibq on
Inbound direct command replication on – sets cmd_direct_replicate on
Outbound direct command replication on – sets dist_cmd_direct_replicate on

You can set async_parser to on and then set the individual parameters independently to fine tune and balance performance and resource consumption.The default for async_parser is off. Set async_parser off to reset the individual parameters to their default setting. You must set the Replication Server site version to 1571 or later before you can set ascii_pack_ibq on. If the site version is earlier than 1571, setting async_parser on only sets exec_prs_num_threads, cmd_direct_replicate, and dist_cmd_direct_replicate.

Restart the distributor with suspend distributor and resume distributor after you use async_parser. Replication Server restarts the associated Replication Agent when you set async_parser on.

Asynchronous Parser
Configure additional Executor threads to parse commands from Replication Agent to reduce the time Replication Agent waits for the Executor.
ASCII Packing
Reduce the stable queue storage space consumed by packed commands in the inbound queue by using ASCII packing with the asynchronous parser.
Direct Replication for Inbound Commands
Reduce command transformation in the inbound replication path between the Replication Server EXEC and DIST modules to improve replication performance.
Direct Replication for Outbound Commands
Reduce command transformation in the outbound replication path between the Replication Server DIST and DSI modules to improve replication performance.
SQM Command Cache Memory Configuration
The SQM command cache memory configuration settings depend on the total amount of memory available to Replication Server, the number of inbound and outbound queues, and the transaction profile, which depends on the command size.

Parent topic: Suggestions for Using Tuning Parameters