When a space shortage occurs in an RDAREA, the size of the RDAREA can be expanded by means of automatic addition of segments, provided that there is sufficient free space in the HiRDB file system area. This process is called RDAREA automatic extension. Figure 15-1 illustrates RDAREA automatic extension.
Figure 15-1 RDAREA automatic extension
A contiguous area in a HiRDB file system area is called an extent. The maximum number of extents in a HiRDB file is 24. During automatic extension, if contiguous free space can be allocated following the last allocated extent of the target HiRDB file, the number of extents does not increase. However, if non-contiguous free space is allocated, the number of extents increases. Extent information can be checked with the pdfls command.
When RDAREAs are deleted, reinitialized (allocated size is reduced or with reconstruction is specified), or combined, allocated extents are deleted or their sizes are reduced, as a result creating fragmented free spaces within the HiRDB file system. Note that if RDAREAs are added, expanded, or reinitialized in this state, multiple extents may be allocated to a single HiRDB file even if automatic extension is not executed.
Automatic extension can be applied to the following RDAREAs:
The following is the procedure for setting automatic extension: