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Limited support BMC provides limited support for this version of the product. As a result, BMC no longer accepts comments in this space. If you encounter problems with the product version or the space, contact BMC Support.BMC recommends upgrading to the latest version of the product. To see documentation for that version, see DASD MANAGER PLUS for DB2 13.1.

Post-installation considerations

Review the following topics for recommendations and requirements before you use DASD MANAGER PLUS:

Recommendations for reducing system resource requirements

The following features require additional memory, space, and CPU cycles:

  • Maximum lengths for the following 2000 byte statistics columns:
    • HIGHKEY
    • HIGH2KEY
    • LOWKEY
    • LOW2KEY
  • Partial statistics rollup for COLCARDDATA and COLDISTDATA, resulting in increased data (up to 3400 bytes)
  • Maximum length of 2000 bytes for the COLVALUE column for column data collection
  • Name lengths increased from 30 to 128 characters and from 8 to 128 for creator names

These features affect the amount of time required to process columns (based on column length and the number of variable-length columns used), indexes, and partitioned table spaces. To minimize the system requirements when running DASD MANAGER PLUS jobs, BMC offers the following recommendations:

  • Carefully consider the values you plan to set for each of the following fields, based on which columns are needed for SQL optimization. Specifying certain values for these columns can be expensive in terms of CPU processing time and main storage occupancy.

    • FREQTYPE

      Consider specifying a value other than L (least frequent values) or B (both least and most frequent values).

    • KEYCARD

      Consider specifying N, which indicates not to count the cardinality of concatenated keys.

    • NUMCOLS

      Consider specifying 1 to collect frequent values only for the first key column.

    • COUNT

      Consider using a low value when specifying the maximum number of frequent values to collect.

    • TABLE ALL

      Consider specifying N and gathering statistics only on tables for which you really need to gather statistics.

  • Consider collecting column statistics only when an object has changed significantly. To help determine which objects are candidates for new statistics collection, use BMCTRIG.
  • Although BMC has increased the default DDL allocation size, you should review your current allocations and ensure that the new tables are large enough to accommodate the increased data.
  • Review the limit that you set for the REGION parameter (the amount of virtual storage that the utility uses). For more information about this parameter, see REGION parameter.
  • BMCSTATS processes all table spaces and indexes in the SYSIN stream during initialization. Doing so optimizes the collection of related object column statistics and enables multitasking but requires additional memory for processing. Consider using multiple jobs if you are processing large objects or analyzing large amounts of index or column data. You can use BMCTRIG to split the objects across multiple jobs, separating larger objects from smaller ones by using exclude rules. You can run BMCSTATS against the larger objects with a smaller number of tasks, and run BMCSTATS against the smaller objects with a larger number of tasks.
  • If you are processing a large number of partitions, you might need to increase the size of the BMCSYNC table space from the standard size that was allocated during installation. Estimate this allocation based on all of the following factors:
    • Number of utilities that you are running concurrently
    • Number of partitions that you are processing concurrently
    • Number of files that you are dynamically allocating

  • If you are experiencing SQL -911 errors followed by BMCSTATS job termination, you might need to specify 911ACTION IGNORE so that BMCSTATS ignores SQL -911 errors and continue processing.

    Objects that receive SQL -911 errors still need to be reprocessed.

  • If you are experiencing SQL -911 errors or Db2 locking problems during the BMCSTATS stats table update phase, you can specify OPTIMIZECOMMIT NO to guarantee that commits occur after every SQL DELETE, INSERT, or UPDATE statement.

    Warning

    Important

    Specifying OPTIMIZECOMMIT NO increases BMCSTATS processing overhead.

  • If you are processing a very large number of objects and have experienced main storage depletion problems, you can specify QUIESCEINTERVAL .

    Specifying a value in the range of 10000 through 1000000 for QUIESCEINTERVAL allows BMCSTATS to consolidate and release main storage after the specified number of partitions are processed. Do not specify the keyword if you have not encountered main storage depletion errors with BMCSTATS.

MEMLIMIT system parameter

DASD MANAGER PLUS requires above-the-bar memory and might abend if it attempts to access storage and this memory is not available.

The default value for the System Management Facility (SMF) MEMLIMIT parameter is 2 GB. This value is set in member SMFPRM xx in SYS1.PARMLIB. Use any of the following methods if you need to override the default value:

  • Specify REGION=0M, which gives you unlimited below-the-bar and above-the-bar memory.
  • If REGION=0M is not specified, specify MEMLIMIT=NOLIMIT to allow unlimited above-the-bar memory; in this case, your z/OS system administrator can still control above-the-bar memory allocations by using the System Management Facility (SMF) user exit facilities.
  • If the above-the-bar memory limits that are enforced through system defaults are inadequate, contact your z/OS systems administrator.
  • If you specify ATBWORKAREA YES , above-the-bar memory requirements are significantly increased. ATBWORKAREA NO is the default.

 

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DASD MANAGER PLUS for DB2 12.1