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The ALTER statement changes the compression attributes of a data set or pattern that is currently defined to CA Compress. There are no defaults.
ALTER{DSNAME=datasetname| PATTERN=patternname}
[,ADDPATHS=(pathname1[,...,pathname5)]
[,DELPATHS=(pathname1[,...,pathname5)]
[,SUPEREXP|
FDT=fdtname[,STANDARD]DICTIONARY=dictionary]
[,SCHEDULED={SCHED|OPEN|LOAD}]
[,EXCLUDE={YES|NO}]
[,RELEASE={percent|NO}]
[,NEWNAME=newdatasetname]
[,NON-COMP=#]
[,SCOPE=CICS|ALL]
[,IAM=YES|NO]
[,UEXIT=YES|NO],
[,FORCE]
Specifies the name of the Control File entry that is being ALTERed. For a simple rename function (NEWNAME is the only other parameter specified), this value can be a cluster, data component, or path name. For all other functions, only the cluster name is valid.
Specifies the pattern name that is to be ALTERed. The pattern can contain any character that is valid in a data set name along with the special characters ?, *, ! and /. These special characters are defined in the section Syntax Rules in this chapter.
Specifies the path names to be added to the existing Control File entry.
Specifies the path names to be deleted from the existing Control File entry.
Specifies the type of compression desired for the data set or pattern being ALTERed.
The optional parameter STANDARD can be specified only in conjunction with the FDT=fdtname parameter. It informs the CA Compress Subsystem that the FDT specified should be used to provide the Huffman tables only and that the RDL specified in the FDT should be ignored. The STANDARD parameter allows one FDT to be used for a number of data sets that can share character distribution characteristics but not key structure. The FDT is assumed to be STANDARD if the FDT parameter specifies a name of the form STDTBLxx (where xx is a numeric value from 01 to 06). The DICTIONARY parameter can specify a CA-supplied IBM Hardware Compression dictionary of the form HC#STDxx (where xx is numeric 01 to 05).
The SUPEREXP parameter requests the low-overhead compression algorithm called Super Express Compression.
The SCHEDULED parameter provides the capability to compress each record in a data set as it is accessed. OPEN specifies that the data set should start being compressed the next time it is opened for OUTPUT. LOAD specifies that compression should begin the next time the data set is completely reloaded; the entire data set is compressed during the load process. SCHED specifies that the data set is currently compressed and was compressed as SCHEDULED. Because SCHEDULED data sets have certain requirements, CA Compress must be made aware that these data sets were originally SCHEDULED. The compression type of a SCHEDULED data set can be changed, by using the ALTER statement, any time before compression begins.
Specifies that the data set is excluded from compression (YES), or no longer excluded from compression (NO).
Specifies that any excess space should be released from the space that the VSAM cluster occupies. It also provides the percentage of the space that is to be RETAINED. The percentage is applied to the file size (high-used RBA) and the resulting value is added to the file size. The resulting value is the amount retained. If the value NO is coded, the release option is turned off for this data set.
Note: A value of 0 for the RELEASE parameter causes the default value of 10% to be used.
Specifies the new data set name or data set pattern for a previously-defined entry. This parameter can be specified in conjunction with any other parameters when renaming a cluster or pattern entry.
Note: For data component and path names, this is the only valid parameter.
Specifies a file's original noncompressible field length for other than custom Huffman methods instead of allowing CA Compress to calculate it from the data set's attributes. This parameter is especially helpful for exempting nonkey bytes from compression or for setting aside noncompressible bytes at the beginning of ESDS records. Do not code a value less than the end of the last key.
Specifies whether data set should be considered defined as compressed only under CICS (SCOPE=CICS) or always (SCOPE=ALL). This parameter is primarily intended as a conversion aid. The default is the current value in the record.
Changes this Control File entry to apply to IAM (Innovation Access Method) data sets as well as VSAM data sets (YES), or to not include IAM data sets (NO).
Specifies whether the Transparency User Exit is to be invoked during compression and expansion of each record.
Allows ALTER to be done even if the data set is already compressed. Valid uses include changing values such as the noncompressible area on a new entry created from an existing entry by the COPY statement, which can appear compressed even though it is a new entry, or to correct an error in a new VSAM entry added with SCHED=SCHED. Misusing this parameter can cause compressed data not to expand, or can cause new records to be compressed differently from those already compressed in the data set.
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