Customers who need faster performance from database apply processes can take advantage of the functionality made available through the DB apply cache (DBAPYCACHE) policy on the Set MIMIX Policies (SETMMXPCY) command. The DBAPYCACHE policy results in significant, general improvement in database apply performance. This functionality is ideal for customers who have allocated a highly active file to its own apply session and need more performance but do not want to purchase the Journal Caching feature from IBM (High Availability Journal Performance IBM i option 42, Journal Standby feature and Journal caching).
Notes:
Database apply caching within MIMIX cannot be used in resource groups or data groups that are configured for multithreaded database apply processing. The DBAPYCACHE policy is ignored when multithreading is used.
Database apply caching within MIMIX cannot be used in conjunction with IBM option 42. For more information about MIMIX support for IBM option 42, see Configuring for high availability journal performance enhancements.
Environments configured for cascading should not use database apply caching on the intermediate system. For more information about cascading, see Configuring for cascading distributions.
When the DBAPYCACHE policy is enabled, before and after journal images are sent to the local journal on the target system. This will increase the amount of storage needed for journal receivers on the target system if before images were not previously being sent to the journal.
The DBAPYCACHE policy is shipped so that it is enabled at the installation level. If the policy is not enabled in your environment, do the following from a management system to enable the DBAPYCACHE policy:
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From the command line type
SETMMXPCYand press F4 (Prompt). -
For the Data group definition, do one of the following:
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To set the policy for the installation, verify that the value specified for Data group definition is *INST.
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To set the policy for a specific data group, specify the full three-part name.
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Press Enter. You will see all the policies and their current values for the level you specified in Step 2.
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Use the Page Down key to locate the DB apply cache policy. Specify *ENABLED.
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To accept the changes, press Enter.
Changes to this policy are not effective until the database apply processes for the affected data groups have been ended and restarted.