-
Title
What are the post parameters that help performance? -
Description
Single threaded Post (STP) is slow.
-
Cause
Post is heavily backlogged.
-
Resolution
Increase value of SP_OPO_READRELEASE_INTERVAL to 5000 or 10000 and SP_QUE_POST_SHMSIZE to 32mb, 64 mb or 128mb in bytes as needed.
When running on STP these two parameters can be tuned to help improve the performance.
The parameter SP_QUE_POST_SHMSIZE can now be set globally as well as at a named Post queue level. This is how it is set at a queue level:
sp_ctrl>set param SP_QUE_POST_SHMSIZE queue <post_queue_name> <value>
Then bounce the Post queue in question.
-
Additional Information
SP_QUE_POST_SHMSIZE : This parameter determines the specific shared-memory size for the post queue. Increasing this parameter might require an increase in the maximum shared memory segment size in your system settings. sp_cop should be bounced for this parameter to take effect. Set SP_QUE_POST_SHMSIZE to 32mb, 64 mb or 128mb. Set this parameter in bytes. Note that if you have multiple post queues each post queue will be using as much memory. Make sure you have enough memory on the system.
Starting with SharePlex 8.6, the unit of the following parameters have changed from bytes to megabytes (MB). Hence one may want to change all references to the parameters from bytes to megabytes. Here are the latest description of the parameters: SP_QUE_POST_SHMSIZE This parameter determines the specific shared-memory size for the post queue. IMPORTANT: Increasing this parameter might require an increase in the maximum shared memory segment size in your system settings. Default: 32 megabytes Range of valid values: integer greater than 0 Takes effect: When sp_cop is restarted SP_QUE_Q_SHMSIZE This parameter determines the specific shared-memory size for the capture and export queues. Default: 8 megabytes Range of valid values: integer greater than 0, no maximum Takes effect: When sp_cop is restarted
SP_OPO_READRELEASE_INTERVAL: It controls how often Post read/releases. Normally, Post performs a read/release after it receives each COMMIT, which means it purges that transaction's data from the queue as part of the checkpoint recovery process. For smaller transactions, this causes excessive I/O on the target system and slows Post. If most transactions are small, you can set this parameter so that Post read/releases after a certain number of messages instead of after every COMMIT.