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Bypass Compression option

This option allows you to exempt a program from compression and expansion processing by DATA ACCELERATOR Compression.

If you are executing a program that uses an unsupported access method or technique, this option has no effect. The access method or technique is still unsupported.

If you set the BYPASS option to Yes, you bypass or avoid compression and expansion processing by DATA ACCELERATOR Compression for data accessed by registered programs. Bypassing a program saves processing time, tape space, and DASD space. For example, data sets that have been backed up in compressed format are reloaded in compressed format. You avoid the overhead of expanding and recompressing all data sets.

Warning

Note

This option should be used with caution because I/O errors and data loss can occur with programs using this option. The BYPASS option occurs at the program level regardless of the settings within the data set registration entry. This option is in effect for each invocation of the program and for all data sets accessed by the registered program. Use of this option should be thoroughly tested to ensure that the results are the ones expected.

If you set the BYPASS option to No, you do not bypass compression or expansion processing by the product. You allow compression and expansion processing by DATA ACCELERATOR Compression for the registered programs. When you allow compression, you can specify the location where compression and expansion processing takes place by using the Compression Location option.

This option has no effect on programs that use unsupported access methods or techniques. If you set the BYPASS option to No for a program that uses unsupported access methods or techniques to allow compression or expansion processing for that program, DATA ACCELERATOR Compression still does not compress or expand the data for that program.

As part of the installation process, registration entries are added for certain programs with BYPASS set to Yes. See member DACPROG of the BMC.DAC.JCL data set. This member contains the JCL to register certain programs and an explanation of why each registration entry is needed.

Warning

Note

DATA ACCELERATOR Compression allows you to restrict access to the program portion of the Registration panels and to entries in the REGISET. You can implement security through your existing security system or by modifying the supplied user authorization exit. For more information on implementing security for program registration, see BMC Software Subsystem.

Even though DATA ACCELERATOR Compression discovers programs that use EXCP or other unsupported access methods through its auto registration process, you should register these programs for BYPASS(YES) to reduce the overhead associated with the auto registration process. Most commercial backup and recovery programs use EXCP to increase processing and decrease run times. DATA ACCELERATOR Compression does not compress or expand data for these programs. If the data was originally compressed, the data on the backup file is compressed. If the data was not compressed originally, the data on the backup file is not compressed, even if a registration entry of BYPASS(NO) is specified to allow compression and expansion for that program.

Do not bypass commonly used utilities, such as IDCAMS or IEBGENER. You can create an alias for IDCAMS because you can use the IDCAMS backup and recovery facilities without expanding data. For instructions about creating an alias for IDCAMS, see BMC Software Subsystem. Then, add program entries for program name BCSAMS where BYPASS is set to Yes. When you want to backup or restore data using IDCAMS without data expansion (or compression), specify PGM=BCSAMS rather than PGM=IDCAMS on your EXEC statement.

Warning

Note

For the VSAM component, if you are using IDCAMS to perform a REPRO to a fixed-length, (RECFM=F or FB) non-VSAM file, you must change the DCB for this file to variable length (RECFM=V or VB) when you use BCSAMS.

Parameter

Description

Components

Non-VSAM component

VSAM component

REGISET Entries

Program entry

ISPF Panel

Bypass compression field

Batch Utility

BYPASS

Global Commands

Not applicable

JOB Step Overrides

Not applicable

Values

This option has the following values:

  • Yes - Bypass compression processing for data sets accessed by this program.
  • No - Allow compression processing for data sets accessed by this program.
Warning

Note

You must also have enabled the non-VSAM component or the VSAM component, or both, by using the bcssid DAC NONVSAM ENABLE or bcssid DAC VSAM ENABLE command for the intercept to occur.

Default

Allow compression or expansion processing of data sets accessed by a particular program. Default processing works as follows:

  • If a data set is registered for compression, the data is compressed when a program writes data to the data set, and expands the data when a program reads data from the data set.
  • Only programs that require exception processing must be registered.
  • If you bypass (exempt a program from) processing by registering a program, program reads/writes do not cause compression or expansion in the data set accessed by the program.
  • A registered program affects only data sets compressed by DATA ACCELERATOR Compression. A registered program has no effect on noncompressed data or on the use of registered programs with noncompressed data.


Related topics

Options-for-DATA-ACCELERATOR-Compression

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DATA ACCELERATOR Compression 1.6