Using CA Datacom/DB Utility (DBUTLTY) › Area Level DBUTLTY Control › MULTUSE= Keyword

MULTUSE= Keyword

The MULTUSE= keyword, for area level DBUTLTY control, is an option in the following DBUTLTY functions:

• BACKUP for Data Areas
• EXTEND for Data Areas
• EXTRACT
• INIT for Data Areas
• LOAD for Data Areas
• Forward RECOVERY
• REORG
• REPLACE
• RETIX

The following gives details about using MULTUSE= in the previously listed functions:

• EXTEND and INIT for Data Areas

  Specifying MULTUSE=YES in the EXTEND and INIT functions for data areas allows a single area in a database to be initialized or extended with no disabling of the other areas in the database. When MULTUSE=YES, the functions execute in a new format that is a combination of Multi-User Facility and Single User modes. The database involved must be able to be opened for update in the Multi-User Facility address space. The area, however, must have no tables open. Once begun, the functions do not allow other tasks to open any tables in the area being processed. Other tables in the database, but not in the area, may be open for read or update in the same Multi-User Facility. The actual data set open is performed in the utility region, and the JCL requirements are applied to the utility region.

  When you specify or allow the default of MULTUSE=NO in the INIT or EXTEND functions for data areas, the functions execute as in versions prior to Version 11.0, that is, completely Single User in mode.

• LOAD and RETIX

  In LOAD and RETIX functions that do not use the KEYNAME= keyword, specifying MULTUSE=YES allows a single area in a database to be loaded or have its index rebuilt, with no loss of read and update access to other areas in the database. When MULTUSE=YES, the functions execute in a new format that is a combination of Multi-User Facility and Single User modes. The database involved must be able to be opened for update in the Multi-User Facility address space. The area, however, must have no tables open. If the database is currently open, CA Datacom/DB closes this area with the area close (you would need to close the area yourself only if the database is open and you need the Multi-User Facility to close it, so that any type of open data set lock can be necessary in order to scratch and reallocate the data set). Once started, the functions do not allow other tasks to open any tables in the area being processed. Other tables in the involved database, but not in the area, may be open for read or update in the same Multi-User Facility.

  With MULTUSE=YES:

  • The area is first opened in Multi-User Facility for the LOAD or RETIX.
  • The area is also opened in Single User mode.
  • The data area processing occurs in the utility address space.
  • The key build/sort occurs in the utility address space.
  • The index load/merge occurs in the Multi-User Facility address space. Packages of index entries (about 32k bytes) are sent from the utility to the Multi-User Facility.

  MULTUSE=YES affects several other options. The SORT option becomes required and is an error to be specified as 0. The AREA= keyword becomes required.

  When MULTUSE=NO is specified or is allowed to default in the LOAD and RETIX functions, the functions execute as in versions prior to Version 11.0, that is, the database involved may not be open for update, and all processing executes in the Single User mode.

• RECOVERY (forward only)

  Beginning with Version 11.0, using MULTUSE=YES in the RECOVERY OPTION=FORWARD function of DBUTLTY allows a single area in a database to be recovered with no disabling of the other areas in the database. Forward recovery functionality that existed in versions prior to Version 11.0 remains unchanged.

  For area level DBUTLTY control, three keywords must be provided, MULTUSE=YES, DBID=, and AREA=. The three are a set, that is, if one of the three is specified, the other two must also be specified. When all are provided, the RECBASE and RECJOB functions are not allowed. Using the three area level control keywords, recovery works at the same level as the LOAD, RETIX, INIT, EXTEND, and REORG utility functions.

  When MULTUSE=YES is specified, the area involved must be able to be opened for update in the Multi-User Facility. Once begun, the function prevents other opens for the area. Tables in other areas may be open for other utilities and user applications based upon normal rules. This recovery does not add log recordsIf it fails, it is necessary to restore the data area again and restart the recovery, the same as would be required when running any of the other forms of forward recovery.

  Following are the rules for execution for forward recovery with MULTUSE=YES:

  • Database must be open for update in the Multi-User Facility or able to be opened.
  • No table in the area may have an open for update user.
  • No table in the area should have a read user. CA Datacom/DB does, however, allow it.
  • Area may not currently be being processed by another MULTUSE=YES forward recovery, INIT, EXTEND, LOAD, RETIX, or REORG.
  • The area should be set with ACCESS STATUS=UTLTY. CA Datacom/DB does not, however, absolutely require it.

  In forward recovery, if you specify MULTUSE=NO, or allow the function to default to it, the database involved must be able to be opened for update by the utility address space. This means it is not open for update by any other address space, including a Multi-User Facility. Also, the database should not be open for read, even though CA Datacom/DB does allow it.

• REORG

  Area level DBUTLTY control allows a single area in a database to be reorganized with no disabling of the other areas in the database.

  With MULTUSE=YES, the data-spaces containing index information are defined with a global scope, making them available to the Multi-User Facility. When MULTUSE=YES, the index phase must occur in Multi-User Facility with full interaction with other tasks processing the index and sharing the same buffer pool. Each task does single block reads. The area being reorganized cannot have other users for REORG to start and, once started, it does not allow other users to open.

• REPLACE

  The REPLACE function has table level control, but it interacts with area level controls. For example, if replacing a single table in an area, the area cannot be used by the LOAD function.