Space management of an IMS database
Space within an IMS database can be managed during loading or updating of the database. After an IMS database is loaded, a space management program can assume control from the IMS program for a period of time. During this period of time, the space management program obtains memory addresses of IMS control blocks built by the IMS program and further obtains information about the IMS database. When the IMS program attempts to insert data into the IMS database, either during loading or updating of the database, the space management program reassumes control from the IMS program. The space management program selects a storage location for the data to be stored, and modifies the IMS control blocks to indicate the storage location selected. The space management program may also insert the data into the storage locations selected. Control is then passed back to the IMS program. If segments are to be inserted into the IMS database, and such segments are to be split, then the space management program selects two storage locations for the components of the split segment to be stored. The storage locations selected by the space management program are selected based on IMS database user preferences.
1. A method of managing space within an information management system (IMS) database, wherein said space is managed during loading or updating of said database, comprising:
after said IMS database is loaded, assuming control from an IMS program and obtaining memory addresses of IMS control blocks built by said IMS program and obtaining information about said IMS database;
passing control back to said IMS program;
when said IMS program attempts to insert data into said IMS database, either during loading or updating of said database, reassuming control from said IMS program;
selecting a storage location for said data to be stored;
modifying said IMS control blocks to indicate the storage location selected; and
passing control back to said IMS program.
2. The method of claim 1 , wherein said storage location for said storage data to be stored is selected based on IMS database user preferences.
3. The method of claim 2 , wherein said data includes root segments and said user preferences include storing said root segments in fixed storage locations.
4. The method of claim 2 , wherein said user preferences include storing said data in particular units of work.
5. The method of claim 3 , wherein said data also includes non-root segments and said user preferences include storing non-root segments in a block of memory which also contains the root segment of said non-root segments.
6. The method of claim 5 , wherein said non-root segments are stored in said block of memory which also contains said root segment only if space is available.
7. The method of claim 4 , wherein said data includes root and non-root segments, and said non-root segments are stored in a unit of work which contains the root segment of said non-root segments.
8. A method of managing space within an information management system (IMS) database, wherein said space is managed during loading or updating of said database, comprising:
after said IMS database is loaded, assuming control from an IMS program and obtaining memory addresses of IMS control blocks built by said IMS program and obtaining information about said IMS database;
passing control back to said IMS program;
when said IMS program attempts to insert data into said IMS database, either during loading or updating of said database, reassuming control from said IMS program;
selecting a storage location for said data to be stored;
storing said data in the storage location selected;
modifying said IMS control blocks to indicate the storage location selected; and
passing control back to said IMS program.
9. A program storage media readable by a machine and containing instructions for performing the method contained in claim 1 .
10. A program storage media readable by a machine and containing instructions for performing the method contained in claim 8 .