Performance enhancements

The Db2® 11.5.4 release contains numerous SQL performance enhancements that continue to make the Db2 data server an industrial-strength data server solution that is suitable for any size of organization.

Attention: The enhancements in this topic are included in the Db2 11.5.4 mod pack release, which is available for the following products:
The following table lists performance enhancements that have been added to the Db2 11.5.4 release:
Table 1. Performance enhancements in 11.5.4
Enhancement Description
Faster database activation

Deferred memory commit is now fully supported in production environments which leads to faster database activation. Introduced as a technical preview in version 11.5 GA, this feature improves database activation time by initializing the bufferpool and locklist memory asynchronously in the background. This allows database activation to be complete sooner and for application connections to be connected quicker.

For more information, refer to DB2_DEFER_MEMORY_COMMIT.

Index management improvements Index management performance enhancements have been made in high index contention workload scenarios through improvements to index page split locking mechanisms.
New values for database configuration parameter stmt_conc

Setting stmt_conc to COMMENTS (and COMM_LIT) ensures that SQL statements that are otherwise identical but end with a different simple comment text (beginning with '--') share the same entry in the package cache thus saving space in the package cache and avoiding unneeded compilations. For more information, refer to Statement concentrator.