Some registry and environment variables have changed

Starting in DB2® Version 9.7 Fix Pack 5, this variable has a new option, SQLADM_NO_RUNSTATS_REORG, which allows you to take away the ability of users with SQLADM authority from performing runstats or reorg operations.

Starting in DB2 Version 9.7 Fix Pack 3, this variable has a new setting, FCM_CFG_BASE_AS_FLOOR, which allows you to set a floor value for the fcm_num_buffers and fcm_num_channels database manager configuration parameters so that auto-configuration will not tune below their set value.

• APREUSE, which indicates whether the query compiler will attempt to reuse access plans.
• CONCURRENTACCESSRESOLUTION, which specifies the concurrent access resolution to use for statements in the package

The CM and WC values are also available starting in DB2 Version 9.5 Fix Pack 3 and Fix Pack 4, respectively. The COGNOS_CS, FILENET_CM, MAXIMO, MDM, WAS, and WP values are also available starting in DB2 Version 9.5 Fix Pack 5.

This registry variable enables or disables the administrative task scheduler.

This registry variable allows you to have a backup image file directly written to disk, bypassing the file cache, potentially leading to better memory utilization on Linux platforms. This registry variable is available in Version 9.7 Fix Pack 6 and later fix packs.

This registry variable enables soft invalidation of applicable database objects when they are dropped or altered, meaning that active access to an object that is being invalidated can continue.

This registry variable allows dynamic statements containing untyped parameter markers to use deferred prepare semantics in CLI and JDBC applications. When set to YES, any untyped parameter markers derive their data types and length attributes based on the input descriptor from subsequent OPEN or EXECUTE statements. In previous releases, or when set to NO (the default) compilation of such dynamic statements fails.

On Linux operating systems, you can set this registry variable with the FCM_MAXIMIZE_SET_SIZE token to preallocate a default 4 GB of space for the fast communication manager (FCM) buffer. The token must have a value of either YES or TRUE to enable this feature.

This environment variable allows you to specify whether add partition operations are to be performed offline or online. The default setting of FALSE indicates that DB2 partitions can be added without taking the database offline.

This variable enables the HADR reads on standby feature. When DB2_HADR_ROS is enabled on the HADR standby database, the standby accepts client connections and allows read-only queries to run on it. This registry variable is available in Version 9.7 Fix Pack 1 and later fix packs.

This variable specifies operations that are not to modify the history file, thereby reducing potential contention on the history file This registry variable is available in Version 9.7 Fix Pack 6 and later fix packs.

On Windows operating systems, if you enable extended security, this registry variable can limit the operating system permissions of the fenced routines that run under the fenced mode process (db2fmp).

Starting in Version 9.7 Fix Pack 7, you can use this variable to specify the maximum size a snapshot or snapshot estimate can be, thereby preventing large global snapshots from causing memory usage spikes.

This variable allows the use of NCHAR, NVARCHAR, and NCLOB data types in Unicode databases. When it is set to ON, various national character related functions such as NCHAR() and TO_NCHAR() are also supported.

This variable allows users to continue using the sqlugtpi and sqlugrpn APIs to return, respectively, the distribution information for a table, and the distribution map offset and database partition for a row. When this variable is set to OFF, the distribution map size for new or upgraded databases is increased to 32 768 entries and you have to use the new db2GetDistMap and db2GetRowPartNum APIs.

Starting in Version 9.7 Fix Pack 3, you can use this variable to modify the behavior of various aspects of the DB2 internal infrastructure. If you set this variable with the MLN_REMOTE_LISTENER option, applications can connect directly to each logical database partition instead of routing requests through the database partition server that is assigned to logical port 0. If you set this variable with the ENHANCED_ROLLBACK option, rollback requests for units of work are sent only to logical database partitions that participated in the transaction.

Starting in Version 9.7 Fix Pack 6, this DB2 registry variable is the primary point of configuration for in-database analytics with the SAS embedded process.

This variable allows you to control the amount of caching of previously used sections in the SQL Workspace. You would adjust the setting for DB2_SQLWORKSPACE_CACHE based on how much of the SQL workspace you want to make available for reuse, which can result in some performance improvements for OLTP workloads.

This variable coerces the isolation level requested by applications and statements running on an active HADR standby database to Uncommitted Read (UR). When DB2_STANDBY_ISO is set to UR, isolation levels higher than UR are coerced to UR with no warning returned. This registry variable is available in Version 9.7 Fix Pack 1 and later fix packs.

Starting in DB2 Version 9.7 Fix Pack 5, you can use this registry variable to modify the self tuning memory manager (STMM) shared memory segment in order to mitigate downlevel instance compatibility issues.

This variable allows the fast allocation file system feature to reserve table space, and speed up the process of creating or altering large table spaces and database restore operations. This variable is available with DB2 Version 9.7 Fix Pack 1.