Utility Statements › CONVERT PAGE › Usage

Usage

You can process an entire segment or one or more individual areas using this utility. The utility first identifies the changes that need to be made by comparing old and new definitions for the segment or areas. Once all changes have been identified, it converts one or more files. It is possible to run the utility in parallel to process several files concurrently.

This utility allows you to reassign the page range of an area so that you can consolidate free pages. It also allows you to change the maximum number of records on a page permitting more effective use of the space on a page and more flexibility in choosing page sizes.

To use the feature, you must define one or more new segments and include them in a DMCL, or alter the definition of an existing segment and include it in a new DMCL. The utility requires both the old and new definitions of the affected segment or areas to be available at runtime.

Once the definitions are available, you can execute the utility. There must be enough disk space available to hold all converted files. The converted files can also be written to tape and then copied back to the original database files. Be sure to back up the original database beforehand.

Once all files have been converted, you must make the new segment or area definitions effective.

Page range and radix changes

Page range and radix changes are determined by comparing all source and target area definitions. Regardless of which files are selected for conversion, all differences are applied to all files selected for conversion.

File conversion

File conversion is performed against all files in the specified segment or areas, unless the FILE parameter is specified, in which case only specified files are converted.

File conversion consists of copying a page from the source file to the target file while making any required changes. Page number changes are accomplished by subtracting the old low page and adding the new low page. Maximum records per page changes are effected by breaking up a dbkey into a line and page number using the old information and reassembling it using the new information.

Note: If no changes apply to a selected file it is copied anyway.

The CONVERT PAGE utility also has the following usage considerations:

• If an area that is being converted has a cross-area set or linked constraint, then you must convert all areas touched by the set or link. You must determine what files are affected, and therefore what files must be converted.
• If you need to convert multiple files, the files do not all have to be converted in the same job.
• As long as all changes are identified to each job, you can convert each affected file separately. It may be desirable to run several jobs in parallel to reduce the time required to convert an area.

  Important! It is important that you identify all page range changes that affect a file before the file is converted. Depending on the nature of the page range change, it may not be possible to apply a partial change to a previously converted file.

• If you omit a change identification, then you will need to reapply all changes to the original file, not the converted file.
• You cannot change the number of pages assigned to an area, nor lower the maximum number of records per page to less than the actual number of records stored on any page of an area.
• This utility must run in local mode and with update activity quiesced on the affected areas.
• The source and target files must match in page size and number of blocks. (The source file is copied block for block.) If the target file does not match then the converted file will not be usable by the new file definition.