Table of contents

Performance enhancements

Db2 Version 11.5 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.

The following table displays a list of performance enhancements in V11.5:
Table 1. Performance enhancements in V11.5
Enhancement Description
4K Sector Support Support for storage devices that use a 4KB sector size is now supported in production environments. For details, see the DB2_4K_DEVICE_SUPPORT registry variable.
SQL insert and update statement optimizations SQL based insert and update statements for columnar tables are optimized to support large data sets efficiently, and encoding dictionary creation for such operations are also optimized.
Encoding dictionary support for SQL insert and update Encoding dictionary support for SQL based insert and update statements for columnar tables are enhanced to provide encoding in some cases where encoding was not previously possible including for Declared Global Temporary Tables, Not Logged Initially tables, and tables created using Create Table As Select statements.
Added support for deferred memory commit Support for deferred memory commit is available as a technical preview, but is not supported for production environments until further notice. For details, see the DB2_DEFER_MEMORY_COMMIT registry variable. This feature will improve the performance of large memory allocations, such as those that occur during database activation and some STMM tuning operations.
Automatic collection of column group statistics The automatic statistics collection in Db2 is updated to discover and collect column group statistics on base tables. This feature is not enabled by default. It must be enabled with the new database configuration parameter, AUTO_CG_STATS. When enabled, column group statistics are automatically collected and maintained.