Function level 100 (activated by migration to Db2 12)

Db2 12 starts at function level 100 during migration to Db2 12. In function level 100, fallback to Db2 11 and coexistence with Db2 11 in data sharing remain possible, and most new capabilities in Db2 12 remain deactivated. Function level 100 is comparable in many respects to conversion mode in previous Db2 releases.

In function level 100 (V12R1M100), Db2 runs on Db2 12 code, and virtual storage and many optimization enhancements in Db2 12 become available. However, most new function and new SQL capabilities remain disabled until you activate the function level that introduces them.

The following types of Db2 12 enhancements are introduced in function level 100:

Virtual storage enhancements
Activation of function level 100 introduces all virtual storage enhancements in the initial Db2 12 release.
Optimization enhancements
Activation of function level 100 introduces all optimization enhancements in the initial Db2 12 release. A full prepare is required before any SQL statement can benefit from optimization enhancements. When a full prepare occurs depends on the statement type:
  • For static SQL statements, after bind or rebind of the package
  • For non-stabilized dynamic SQL statements, immediately, unless the statement is in the dynamic statement cache
  • For stabilized dynamic SQL statements, after invalidation, free, or changed application compatibility level
Subsystem parameters
Some new subsystem parameters and changes to existing take effect only after you activate function level 500. However, the following new and changed subsystem parameters take effect in function level 100:
Subsystem parameter Change introduced Incompatible change?
AUTO BIND field (ABIND subsystem parameter) COEXIST behavior is used even when YES is specified. That is, no automatic bind occurs in release coexistence or fallback scenarios when a plan or package that was automatically bound in Db2 11 runs again in Db2 12.

This change prevents repeating automatic remigration binds each time that a plan or package runs again on a different release during coexistence or fallback scenarios. For more information, see Automatic binds in coexistence.

No
ALLOW_UPD_DEL_INS_WITH_UR in macro DSN6SPRM New subsystem parameter. No
ALTERNATE COPY POOL field (ALTERNATE_CP subsystem parameter) New subsystem parameter. No
APPL COMPAT LEVEL field (APPLCOMPAT subsystem parameter) The default value for new installations is changed to 'V12R1M500'. Support is also added for values that correspond to Db2 12 function levels. No
CDDS_MODE in macro DSN6LOGP New subsystem parameter. No
CDDS_PREFIX in macro DSN6LOGP New subsystem parameter. No
MINUTES/CHECKPOINT field (CHKFREQ and CHKMINS subsystem parameters) The default value is changed to 3 and the accepted range for the MINUTES/CHECKPOINT value is now 1 - 5 minutes.

If the CHKTYPE subsystem parameter setting is SINGLE and the CHKFREQ subsystem parameter setting is 6 - 60, Db2 uses 5 for the CHKFREQ setting, issues a warning message, and sets RC=4 for subsystem parameter assembly.

If the CHKTYPE subsystem parameter setting is BOTH and the CHKMINS subsystem parameter setting is 6 - 1439, Db2 uses 5 for the CHKMINS setting, issues a warning message, and sets RC=4 for subsystem parameter assembly.

No
COPY FAST REPLICATION field (COPY_FASTREPLICATION subsystem parameter) New subsystem parameter. No
DEFAULT INSERT ALGORITHM field (DEFAULT_INSERT_ALGORITHM subsystem parameter)
  • The default value is changed from 2 to 1.
  • A new value is added, 0, which means that the basic insert algorithm (insert algorithm 1) is used regardless of the specification at the object level.
No
DISALLOW_SEL_INTO_UNION in macro DSN6SPRM The default is changed from NO to YES. No
DISALLOW_SSARAUTH in macro DSN6SPRM New subsystem parameter. No
EDM SKELETON POOL SIZE field (EDM_SKELETON_POOL subsystem parameter) The default value is changed to 51 200. No
FLASHCOPY XRCP field (FLASHCOPY_XRCP subsystem parameter) New subsystem parameter. No
HSM MESSAGE DS HLQ field (UTILS_HSM_MSGDS_HLQ subsystem parameter) New subsystem parameter. No
INDEX MEMORY CONTROL field (INDEX_MEMORY_CONTROL subsystem parameter) New subsystem parameter.

(SELECTED,AUTO) and (SELECTED,n) settings are added to support enabling fast index traversal only for specific indexes. These settings are used when you specify YES in the FOR SELECTED INDEXES ONLY field on panel DSNTIP71.

No
INLISTP in macro DSN6SPRM The default value is changed to 1000. No
LOAD FORMAT DELIMITED IMPLICIT DECIMAL SCALE (LOAD_DEL_IMPLICIT_SCALE subsystem parameter) New subsystem parameter. No
LOAD RO OBJECTS field (LOAD_RO_OBJECTS subsystem parameter) New subsystem parameter. No
MFA AUTH UNUSED TIME field (MFA_AUTHCACHE_UNUSED_TIME subsystem parameter) New subsystem parameter. No
RID POOL SIZE field (MAXRBLK subsystem parameter) The default value is changed to 1000000 (1,000,000 kilobytes). No
NPGTHRSH in macro DSN6SPRM The default value is changed to 1, which means that Db2 favors matching index access, through the index with the most matching columns, for tables or partitions that have fewer than one data page. (For SAP installations, the default value remains 10.) No
RO SWITCH TIME field (PCLOSET subsystem parameter) The default value is changed to 45. No
PEER RECOVERY field (PEER_RECOVERY subsystem parameter) New subsystem parameter. No
PRIMARY QUANTITY field (PRIQTY subsystem parameter) The default value is changed to 125 (in cylinders—ACLUNIT is removed). No
PROFILE AUTOSTART field (PROFILE_AUTOSTART subsystem parameter) New subsystem parameter. No
REORG TS NOPAD DEFAULT (REORG_TS_NOPAD_DEFAULT subsystem parameter) New subsystem parameter. No
REORG PART SORT NPSI field (REORG_PART_SORT_NPSI subsystem parameter) The behavior of the YES setting is changed so that Db2 always sorts the keys for non-partitioned secondary indexes (NPSIs). To continue with the previous behavior, use AUTO. Yes
RLF SCOPE field (RLFENABLE subsystem parameter) New subsystem parameter. No
REMOTE STATIC SQL field (RLFERRDSTC subsystem parameter) New subsystem parameter. No
STATIC SQL field (RLFERRSTC subsystem parameter) New subsystem parameter. No
STATISTICS COLGROUP DATA SORT STG LIMIT field (STATCLGSRT subsystem parameter) New subsystem parameter. No
STATISTICS PROFILE FEEDBACK field (STATFDBK_PROFILE subsystem parameter) New subsystem parameter. No
MAIN STATS TIME field (STATIME_MAIN subsystem parameter) New subsystem parameter. No
PAGE-LEVEL SAMPLING field (STATPGSAMP subsystem parameter) New subsystem parameter. No
PREVENT_NEW_IXCTRL_PART in macro DSN6SPRM The default value is changed to YES. No
SECONDARY QTY field (SECQTY subsystem parameter) The default value is changed to 15 (in cylinders—ACLUNIT is removed). No
SMF ACCOUNTING field (SMFACCT subsystem parameter) The default value is changed to '1,2,3,7,8'. No
DB BACKUP STG GROUP field (UTIL_DBBSG subsystem parameter) New subsystem parameter. No
LOG BACKUP STG GRP field (UTIL_LGBSG subsystem parameter) New subsystem parameter. No
UTILS USE ZSORT (UTILS_USE_ZSORT subsystem parameter) New subsystem parameter. No
DB2 zHyperLinks SCOPE field (ZHYPERLINK subsystem parameter) New subsystem parameter. No
For more information about subsystem parameter changes in Db2 12, see Subsystem parameter changes in Db2 12.

Activation details for function level 100

After migration from Db2 11, Db2 subsystems and data sharing members are at function level 100. The Db2 catalog level is V12R1M500. Subsystems and data sharing members at function level 100 can coexist with Db2 11 new-function mode.

After the activation of function level 500 you can return a subsystem or group member to function level 100*. You can also activate function level 100* in new Db2 12 installations. However, Db2 subsystems and data sharing members at function level 100* cannot coexist with or fall back to Db2 11.

Catalog level for function level 100

Db2 12 function levels 100 and 500 require catalog level V12R1M500. Catalog level V12R1M500 is the result when you install a new Db2 12 subsystem, or when you tailor the catalog during migration to Db2 12, as described in Migration step 19: Tailor Db2 12 catalog: DSNTIJTC.

For a summary of changes in Db2 12, see Catalog changes in Db2 12.