Partial Database Reorganization utility (DFSPRCT1)
You can use the Partial Database Reorganization utility to reorganize parts of your HD database. It can be used when HD databases use secondary indexes or logical relationships.
You tell the utility what range of records you need reorganized.
- In an HDAM database, a range is a group of database records with continuous relative block numbers.
- In a HIDAM database, a range is a group of database records with continuous key values.
Generally, before using the Partial Database Reorganization utility, you would run the Database Surveyor utility. The Surveyor utility helps you determine whether a reorganization is needed and find the location and size of areas of free space. You need to know the location and size of areas of free space so you will know where to put reorganized database records.
The Partial Database Reorganization utility reorganizes the database
in two steps:
- In the first step, the utility produces control tables for use in Step 2, which is when the actual reorganization is done. As an option, the utility can produce PSB source statements for creating a PSB for use in Step 2. The utility also generates reports that show which logically related segments in logically related databases must be scanned in Step 2, and which can be optionally scanned in Step 2. (Some GSAM databases are involved in Step 2 for which a PSB is needed.)
- In the second step, the utility does the actual reorganization. The database records you have specified are unloaded to a data set. The space they occupied in the database is freed. Then database records are reloaded into the database in the range of free space you specified. Finally, all pointers to database records with new locations are changed to point to the new location. A report is produced at the end of Step 2 to tell you what was done.
The following figure shows the input to and output from the Partial Database Reorganization utility.
