Subsystem parameter changes in Db2 12
You can use this information to plan for subsystem parameter changes in Db2 12.
Important: Db2 12 introduces continuous delivery of new capabilities and enhancements in function levels. Most new capabilities become available only after activation of the Db2 12 function level that introduces them, or when applications run with the corresponding application compatibility level. For more information, see Activating Db2 12 function levels.
Subsystem parameter changes in function level 501 and higher
The following changes take effect when you activate function level 501 or higher in Db2 12.
| Function level | Subsystem parameter | Change introduced | Incompatible change? |
|---|---|---|---|
| FL 508 | FTB NON UNIQUE INDEX field (FTB_NON_UNIQUE_INDEX subsystem parameter) | New subsystem parameter | No |
| FL 504 | TS COMPRESSION TYPE field (TS_COMPRESSION_TYPE subsystem parameter) | New subsystem parameter. | No |
| FL 502 | ENCRYPTION_KEYLABEL field in macro DSN6SPRM | New subsystem parameter. | No |
Subsystem parameter changes in function level 500
The following changes take effect when you activate function level 500 in Db2 12.
Subsystem parameter changes in function level 100
The following changes take effect when you migrate to function level 100 in Db2 12.
| 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 |
| DDF_COMPATIBILITY in macro DSN6FAC | A new value is supported: RESET_IFCID402 specifies that Db2 resets IFCID 0402 counters when the associated profile threshold changes. | No |
| DEFAULT INSERT ALGORITHM field (DEFAULT_INSERT_ALGORITHM subsystem parameter) |
|
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 |
| LA_SINGLESEL_ISOCS_CDY subsystem parameter | New subsystem parameter. | 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 |
| MAX UDFS field (MAX_UDF subsystem parameter) | New subsystem parameter. | Yes |
| 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 |
| MANAGE REAL STORAGE field (REALSTORAGE_MANAGEMENT subsystem parameter) | APAR PH47163 improves the behavior when the default setting AUTO is used, and introduces a new value AUTO1, which can be used to revert to the previous AUTO behavior if necessary. For more information, see APAR PH47163. | 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 |
| DDF STATS TIME field (STATIME_DDF subsystem parameter) | New subsystem parameter. | No |
| MAIN STATS TIME field (STATIME_MAIN subsystem parameter) | New subsystem parameter. APAR PH56228 removes the control of the interval of location statistics trace records, IFCIDs 365, 411, and 412 from STATIME_MAIN. |
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 |
| ACCELERATION OPTIONS field (QUERY_ACCEL_OPTIONS subsystem parameter) | New field on panel DSNTIP8A: 13 ENABLE ACCELERATOR SPECIFIC RESULTS | No |
Removed subsystem parameters in Db2 12 (function level 100 and higher)
The following tables lists subsystem parameters that are removed from this version of Db2 for z/OS. Refer to the information for the earlier version for detailed descriptions of the removed subsystem parameters.
| Subsystem parameter | Setting used in Db2 12 | Incompatible change? |
|---|---|---|
| ALCUNIT | CYL, which means that primary and secondary space allocations are always obtained in cylinder units. | No |
| CACHEPAC | 10M, which is the previous maximum value. | No |
| CACHERAC | 10M, which is the previous maximum value. | No |
| CACHE_DEP_TRACK_STOR_LIM | None, because the storage is allocated from the SCB pool. | No |
| CACHEDYN_FREELOCAL | 0, which means that Db2 does not free cached dynamic statements to relieve high use of storage by dynamic SQL caching. | No |
| CATALOG (in DSN6ARVP) | YES, which means that Db2 requires all archive log data sets to be cataloged, regardless of whether they are allocated on disk or tape. | No |
| CHECK_SETCHKP | NO, which means that he CHECK DATA and CHECK LOB utilities do not place objects in CHECK PENDING status if an inconsistency is detected. | No |
| COMPRESS_SPT01 | YES, which means that Db2 compresses the SPT01 table space during the next reorganization of the table space. | No |
| CONTSTOR | NO, which means that Db2 does not periodically contract the working storage area for each thread. | No |
| DB2SORT | ENABLE, which means that Db2 utilities use the Db2 Sort for z/OS product when it is installed. If Db2 Sort for z/OS is not installed, DFSORT is used instead. | No |
| EDMPOOL | None, because all EDM storage is above the bar. | No |
| EDPROP | NO (or DPROP SUPPORT field = 1 on the panel DSNTIPO), which means that Db2 always allows changes to tables defined with DATA CAPTURE CHANGES, but the SQL changes are not propagated. | No |
| CHGDC | NO (or DPROP SUPPORT field = 1 on the panel DSNTIPO), which means that Db2 always allows changes to tables defined with DATA CAPTURE CHANGES, but the SQL changes are not propagated. | No |
| EDPROP | NO (DPROP SUPPORT field = 1 on the panel DSNTIPO), which means that Db2 always allows changes to tables defined with DATA CAPTURE CHANGES, but the SQL changes are not propagated. | No |
| CHGDC | NO (DPROP SUPPORT field = 1 on the panel DSNTIPO), which means that Db2 always allows changes to tables defined with DATA CAPTURE CHANGES, but the SQL changes are not propagated. | No |
| INDEX_IO_PARALLELISM | YES, which means that I/O parallelism is enabled. | No |
| IRLMAUT | Yes, which means that Db2 starts and stops the IRLM automatically. | No |
| IRLMSWT | 120, which was the previous default value and specifies that Db2 abends if the IRLM does not start automatically within two minutes. | No |
| LEMAX | None. Db2 does not require an LE token limit for any package that was bound in DB2 10 or later. Db2 12 supports only packages that are bound in DB2 10 or later. | No |
| LOBVALA | Db2 automatically determines the amount of storage needed for processing LOB values. | No |
| LOBVALS | Db2 automatically determines the amount of storage needed for processing LOB values. | No |
| MGEXTSZ | YES, which specifies that Db2 automatically optimizes the secondary extent allocations of data sets for table spaces and index spaces that have a SECQTY value of greater than zero. | No |
| MINSTOR | NO, which means that Db2 does not use storage management algorithms that minimize the amount of working storage that is consumed by individual threads | No |
| NEWFUN dsnhdecp parameter | None, because the Db2 precompiler and coprocessor no longer use the NEWFUN dsnhdecp parameter. | No |
| OBJECT_CREATE_FORMAT | EXTENDED, which means that new indexes and table spaces are created to use the extended 10-byte RBA and LRSN log record format. | Yes |
| PCLOSEN | 32767, which is the previous maximum value and specifies that Db2 converts a page set or partition from read-write to read-only after this number of consecutive log checkpoints. | No |
| REORG_IGNORE_FREESPACE | NO, which means that the REORG TABLESPACE utility uses the specified PCTFREE and FREEPAGE values. | No |
| RRF | ENABLE, which means that newly created table spaces or newly added partitions on partition-by-growth table spaces are created in the reordered row format. Existing basic row format table spaces are converted to reordered row format by the LOAD REPLACE or REORG TABLESPACE utilities. | No |
| SPT01_INLINE_LENGTH | 32138, which is the maximum size of LOB column data that is maintained in base tables in the SPT01 directory table space. | Yes |
| SQWIDSC | YES, which means that the database manager invalidates but does not quiesce SQL statements in the dynamic statement cache that depend on an object that is the target of a RENAME TABLE or DROP ALIAS statement. | No |
| UTILITY_OBJECT_CONVERSION | NOBASIC, which means that utilities convert existing table spaces and indexes that use 6-byte page format are converted to extended 10-byte page format. Table spaces and indexes that already use extended 10-byte page format cannot be returned to the 6-byte page format. Important: When the NOBASIC setting of the UTILITY_OBJECT_CONVERSION subsystem parameter is in effect, any LOAD, REORG, and REBUILD INDEX utility job that specifies RBALRSN_CONVERSION BASIC always fails. Similarly, if the target object is still in the 6-byte page format, these utility jobs also fail if they specify RBALRSN_CONVERSION NONE. Plan to remove the RBALRSN_CONVERSION option from these utility jobs before applying the PTF for PH26317.
|
Yes |
| UTSORTAL | YES, which means that the utility attempts to allocate the sort work data sets. To increase the possible degree of parallelism, the utility minimizes the number of sort work data sets that are used. If the SORTNUM clause is specified in the utility control statement and the IGNSORTN subsystem parameter is set to NO, the sort program is used to allocate the sort work data sets. The utility also does not allocate the work data sets if they are allocated in the JCL. | No |
| XMLVALA | Db2 automatically determines the amount of storage for processing XML values. | No |
| XMLVALS | Db2 automatically determines the amount of storage for processing XML values. | No |
