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LOGSORT work data set specification description

NGT Recover sorts the log and merges the sorted records with copies and change accumulation files. Sorting the log records allows efficient merging of the copies and log records and, if you are rebuilding indexes, permits index keys to be extracted at the same time. By using the LOGSORT specification, you can code values for the SORTDEVT, SORTNUM, and NUMREC options for the sort. You do not need to have log records to use these options (for example, if no updates to the tables and indexes occurred after the most recent copy was made).

If you use the LOGSORT specification values in the OPTIONS command statement, you can also use them in the RECOVER TABLESPACE, RECOVER INDEX, or RECOVER INDEXSPACE command statement; however, this is not necessary.

If you do not use the LOGSORT specification in the OPTIONS command statement and you code multiple RECOVER command statements with the LOGSORT specification on one RECOVER command statement while taking the default on the other RECOVER command statements, the LOGSORT specification values becomes the default for the other command statements. You can code the LOGSORT specification values on more than one of the RECOVER command statements, but it is not necessary.

Note

All LOGSORT parameters must match if they are used on multiple statements in the same job.

LOGSORT specification values are ignored if the LOGSCAN command is present because LOGSCAN does not invoke a sort.

For more about the LOGSORT option, see LOGSORT strategy.

NGT Recover invokes BMCSORT, which allocates the required temporary sort work data sets. You can perform one of the following actions:

  • Specify SORTNUM and SORTDEVT to direct the allocation

  • Specify neither SORTNUM nor SORTDEVT, and let BMCSORT allocate the work data sets according to sort rules

  • Specify neither SORTNUM nor SORTDEVT, and provide L001WKnn DD statements in the JCL

  • Specify only SORTDEVT, and let BMCSORT determine the number of data sets

If you use L001WKnn DD statements in the JCL, any SORTDEVT and SORTNUM specifications that are present are ignored. If you do not use L001WKnn DD statements and do not specify SORTDEVT or SORTNUM, the values that are supplied in the NGT Recover installation options are used.

SORTDEVT deviceType

SORTDEVT deviceType specifies the device type for the temporary sort work data sets that BMCSORT uses.

If you specify SORTDYN NO (SORTDYN), BMCSORT defaults are used even if you specify a value for SORTDEVT. Otherwise, NGT Recover uses its internal default value, SYSDA, if you do not specify SORTDEVT.

SORTNUM integer

The SORTNUM option affects the allocation of sort work files when BMCSORT is allocating your sort work files dynamically. You can specify an integer value of 1 through 255.

When you specify this option, BMCSORT dynamically allocates the number of sort work files that it needs for each sort task up to the maximum that is illustrated in the following formula:

 maximum dynamically allocated sort work files = n - preallocated sort work files

If you specify integer from 1 through 32, n equals 32. If you specify integer greater than 32, n equals integer.

Note

Preallocated sort work files include sort work files that are allocated in your JCL.

If you do not specify a value for SORTNUM, NGT Recover uses the installation option default.

NUMREC

NUMREC specifies the size of the sort file for the log sort routine. The size is defined as an estimate or the exact number of log records to process and the estimated average length of each log record.

For information about performance implications, see Using.

NUMREC CALC

NUMREC CALC is the default value. Specifying this option allows NGT Recover to estimate the number of log records to be processed by the log sort routine. It estimates that the sort receives one log record per control interval (CI) processed.

NUMREC NOEST

Specifying NUMREC NOEST prevents NGT Recover from passing a file size to the log sort routine.

NUMREC EST integer

Use NUMREC EST integer to specify an estimated number of log records for the log sort routine. integer must be a positive integer.

AVGRECSZ integer

Use AVGRECSZ integer to specify the average length of the log records to sort. If you do not specify AVGRECSZ, NGT Recover determines its value.

NUMREC ABS integer

Use NUMREC ABS integer to specify the exact number of log records for the log sort routine. integer must be a positive integer.

Warning

If the integer parameter is a value that does not represent the true number of log records that are passed to the log sort routine, the log sort routine abends. Use extreme caution when you specify NUMREC ABS.

AVGRECSZ integer

Use AVGRECSZ integer to specify the average length of the log records to sort. If you do not specify AVGRECSZ, NGT Recover determines its value.

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