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SharePlex 8.6.6 - Installation Guide

About this Guide Conventions used in this guide Introduction to SharePlex SharePlex pre-installation checklist Set up SharePlex in an Oracle cluster Set up SharePlex on Amazon Cloud Download SharePlex UNIX Installation and Setup Windows Installation and Setup Assign SharePlex users to security groups Basic SharePlex demonstrations Advanced SharePlex Demonstrations Solve Installation Problems Uninstall SharePlex SharePlex Utilities Appendix A: Advanced installer options Appendix B: Install SharePlex as root Appendix C: SharePlex installed items

Tune SQL Caching

SharePlex caches frequently-used SQL statements for reuse so that they do not have to be parsed and bound every time they recur. This is an adjustable feature of SharePlex that is named SQL Cache. You can tune this feature to maximize its advantages based on the amount of repetitive statements your application generates.

SQL Cache improves the performance of Post only if the same SQL statements are issued over and over again, with no variation except the data values. If that is not true of your environment, then SQL Cache adds unnecessary overhead to the Post process, and you should disable it.

Supported targets


Enable or disable SQL Cache

Control SQL Cache as follows:


Parameter Description


Enables or disables SQL Cache. Enabled by default with a setting of 0. To disable SQL Cache set the parameter to 1. To disable SQL Cache only for batch operations set the parameter to 3, which reduces the amount of memory that Post uses.


Determines the number of active statements to cache per Post session. Post opens 50 cursors per session by default. You can increase or decrease this setting if needed. See Adjust open cursors for additional important information.

Open Target

Parameter Description


Enables or disables SQL Cache. Enabled by default with a setting of 0. To disable SQL Cache set the parameter to 1.

Use the target command:

target r.database [queue queuename] set resources max_active_statements=number_of_active_statements

Determines the number of active statements to cache per Post session. For Open Target databases, Post gets the number of allowed active statements from the ODBC driver. If that value is lower than the setting for max_active_statements, Post stops and returns an error. You can either disable the SQL Cache feature or reduce the value of max_active_statements.

Tune SQL Cache for best performance

Follow these steps to make certain that the number of active statements is optimal for the operations that are replicated.

  1. Determine the hit ratio for cached statements by running sp_ctrl and issuing the show post detail command.
  2. Look for the SQL cache hit count field. It shows the ratio of the total number of messages that are executed without parsing and binding divided by the total number of INSERT, UPDATE and DELETE operations. For example, a hit ratio of 36% indicates that Post is using cached statements 36 percent of the time.
  3. View the hit ratio after several days of typical replication activity to gauge the ideal setting for the number of active statements. If the hit ratio is under 50 percent, increase the parameter value in a small increment of about 5 statements.
  4. Monitor the hit ratio over the next few days. If the hit ratio increases, it means your applications are using all of the cursors allowed for active statements. Continue to increase the parameter value in small increments until the hit ratio remains constant.
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