Adaptation of JCL to large databases

The procedures used for the migration contain default settings that should be changed depending on the volume of the database to migrate.

These parameters (such as SPAOT or SPAGY) define the size of temporary files, output files or sort files.

The following tables contain the correspondence between the number of records or entities of a database in the current session and the size to specify in the parameters of procedures for large-volume files.

The database restoration report (PAC7EU) gives an estimate of the number of records to take into account to calculate the size of large files (parameters in migration procedures).

The LOGICAL number of DATA FILE is significant and can be used as reference records number.

This number of records corresponds to the parameter N used in the following calculation rules.

1. MIBR procedure

1.1. Assignment

The following table lists the ratios to help you set the file assignment parameters in the procedures:
DDNAME Number of tracks for N records Assignment parameters
&&GY N / 130 &SPAGY
&&PACXWD N / 110 &SPATD
&OUTFILE (TA2) N / 185 &SPAOT
Note: The temporary files &&PAC7AT, &&PAC7TA, and &&PAC7TI have the same parameters as &OUTFILE.

The following table shows the stepstgeere these files are used, in the order of the steps in the MIBR procedure.

These files are temporary and are deleted after the last step where they are used, except &OUTFILE, which contains the TA2 file.

It is therefore possible to reserve the disk space for all files or adapt it to the freeing of files space during the procedure execution progress.
DDNAME PACX2 PACS96 PATI 7 PACS91 PACS98
&&PAC7AT     X X  
&&GY X X      
&&PAC7TA   X X    
&&PAC7TI       X X
&&PACXWD X        
&OUTFILE (TA2)         X

1.2 Sort files

It is recommended to assign 2000 CYL by million records, distributed evenly on the various sort files.

2. Procedures MIA1, MIA2, MIA3, and MIA4

For procedures MIA1, MIA2, MIA3, and MIA4, the assignment depends on the 'n' number of entities (batch programs, screens, clients or servers according to the procedure):
Procedure / DDNAME Number of tracks depending on the number of entities Assignment parameters
&OUTFIL2 n * 3 &SPAOT
&OUTFILE n * 6 &SPAOU

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