Db2 server behavior changes

Changes to Db2 registry variables, configuration parameters, database physical design characteristics, and database authorities and privileges can result in Db2 server behavior changes that might impact your upgrade.

Generally, instance profile variables that you set in your Db2 profile registry or your system environment retain their values after an instance upgrade. Some global profile registry variables, such as DB2SYSTEM and DB2PATH, are set by the Db2 installation procedure or instance upgrade. However, the global profile registry variables that you set by running the db2set command with the -g option are not upgraded. Therefore, you must define them after upgrade.

Existing database and database manager configuration parameters also, generally, retain their values after upgrade. However, the default values assigned to new parameters or the new default values assigned to existing parameters might change the behavior or performance of your applications.

Changes that impact all pre-version 11.5 releases

New registry variables
New registry variables that are introduced in Db2 version 11.5 have no impact on Db2 upgrade.
For more information, see Some registry and environment variables have changed
Changes to existing registry variables
The following table describes the upgrade impact of changes to existing registry variables:
Table 1. Changes to existing registry variables
Name Upgrade impact
DB2DSDRIVER_CFG_PATH This variable now specifies multiple configuration files at same or different locations with different names. If filename is not specified in a path and name pair, then the file name defaults to a value of db2dsdriver.cfg.
For more information, see Some registry and environment variables have changed
Deprecated and discontinued registry variables

You should remove the use of registry variables that are deprecated because the functionality associated with the variable is obsolete or has been replaced by new functionality. See What's changed to determine the upgrade impact of discontinued registry variables.

If you are upgrading from version 10.5 or earlier, consider removing deprecated registry variables in pre-version 11.5 releases because the functionality associated with the variable is obsolete or replaced by new functionality. Also, remove the use of discontinued registry variables in pre-version 11.5 releases as they do not have the intended effect.

New database manager configuration parameters
New database manager configuration parameters that are introduced in version 11.5 have no impact on Db2 upgrade. If you are upgrading from version 10.5, review new database manager configuration parameter in version 11.1 that have an impact when upgrading from those releases. See Db2 server behavior changes for details.
Changes to existing database manager configuration parameters
Changes to database manager configuration parameters introduced in version 11.5 have no impact on Db2 upgrade. If you are upgrading from version 10.5, review the changes for database manager configuration parameters in version 11.1 that have an impact when upgrading from those releases. See Db2 server behavior changes for details.
Deprecated and discontinued database manager configuration parameters

Refer to What's changed for any deprecated or discontinued database manager configuration parameters.

New database configuration parameters

The following table describes the upgrade impact of the default values of new database configuration parameters:

Table 2. New database configuration parameters
Name Upgrade impact
dft_table_org This parameter specifies whether a user table is created as a column-organized table (value COLUMN) or a row-organized table (value ROW) when the ORGANIZE BY COLUMN or the ORGANIZE BY ROW clause is not specified on the CREATE TABLE statement.The default value for this parameter is ROW, which has no impact on upgrade. If you have DDL scripts and you plan to change the default orientation of tables, modify your exiting scripts to specify the ORGANIZE BY COLUMN or the ORGANIZE BY ROW clause for the CREATE TABLE statements to ensure that tables are created with the proper orientation regardless of the setting of this parameter.

For more information, see Changes to database configuration parameters.

Changes to existing database configuration parameters

The following table describes the upgrade impact of changes to existing database configuration parameters:

Table 3. Changes to existing database configuration parameters
Name Upgrade impact
hadr_syncmode In version 10.5, the default value for hadr_syncmode is changed from NEARSYNC to ASYNC for Db2 pureScaleĀ® databases. For all other database types, the default for hadr_syncmode remains NEARSYNC.
hadr_target_list In version 10.5, initializing HADR without setting this parameter is deprecated. You should set this parameter regardless of the number of standby databases as part of the initialization process.

For more information, see Changes to database configuration parameters.

Deprecated and discontinued database configuration parameters

You must remove the use of database configuration parameters that are deprecated and discontinued because the functionality associated with the variable is obsolete or replaced by new functionality. Refer to What's changed for any deprecated or discontinued database configuration parameters.

Changes to physical design characteristics of databases
Review the items in what's new and what's changed to determine whether there are any changes to the physical design characteristics of databases that impact upgrade.
Changes to authorities and privileges

There are no changes to the authorities and privileges in this release.

See Upgrade impact from Db2 command changes and Upgrade impact from SQL statement changes for a summary of Db2 command and SQL statement changes with upgrade impact. See the Command Reference and SQL Reference for details about all the changes in authorization.