Automatic extension can be applied to the following RDAREAs:

• Data dictionary RDAREAs
• User RDAREAs
• Registry RDAREA
• Data dictionary LOB RDAREAs
• User LOB RDAREAs
• Registry LOB RDAREA

HiRDB automatically extends RDAREAs when any of the automatic extension triggers described below occur.

• When the number of free segments within a RDAREA has fallen to or below the number of segments that are set to be extended in a single automatic extension
  For example, when the number of segments that are extended in a single automatic extension is set to 50, if the number of free segments falls to or below 50 segments, automatic extension occurs.
  
• When there are no free segments within an RDAREA and a new segment cannot be allocated

You can specify an automatic extension trigger in the pd_rdarea_extension_timing operand. For details, see the manual HiRDB Version 9 System Definition.

To apply RDAREA automatic extension, we generally recommend that you select Method 1. Because Method 1 automatically expands the HiRDB file system area to the maximum HiRDB file size (64 gigabytes), it is easy to estimate the area size and expand the database.

However, because Method 1 is subject to the following restrictions, select Method 2 for systems to which Method 1 cannot be applied.

• Because a HiRDB file system area is allocated to each RDAREA, the same number of HiRDB file system areas as the number of RDAREAs must be created.
• Because a HiRDB file system area is automatically expanded to 64 gigabytes as long free space is available on the disk, you cannot set an upper limit for disk usage.

The following subsections describe the procedures for setting automatic extension.

(a) Method 1

With this method, if RDAREA automatic extension causes the HiRDB file system area to exceed its upper size limit, the HiRDB file system area is automatically extended to the maximum HiRDB file size (64 gigabytes).

Procedure

1. If necessary, change the HiRDB system definition.
   Specify an automatic extension trigger in the pd_rdarea_extension_timing operand. For details about how to change the HiRDB system definition, see the HiRDB Version 9 System Operation Guide.
   
2. When you create the HiRDB file system area using the pdfmkfs command, specify the -a option.
3. When you create the RDAREA, use a utility control statement^# to specify the number of segments by which the RDAREA can be extended.

#

This can be specified in the CREATE RDAREA, EXPAND RDAREA, INITIALIZE RDAREA, or ALTER RDAREA statement of the database initialization utility, the database structure modification utility, or the registry facility initialization utility.

(b) Method 2

With this method, RDAREAs are automatically extended to the upper size limit set for the HiRDB file system area. If the HiRDB file system area has no free space available, automatic extension cannot occur. In such a case, either extend the RDAREA or reorganize the tables and indexes within it. If the number of extents exceeds the upper limit of 24, combine the extents of the HiRDB file system area into a single extent, or extend the RDAREA. For details about how to combine extents and HiRDB file system areas, see the HiRDB Version 9 System Operation Guide.

Procedure

1. If necessary, change the HiRDB system definition and specify an automatic extension trigger in the pd_rdarea_extension_timing operand. For details about how to change the HiRDB system definition, see the HiRDB Version 9 System Operation Guide.
2. When you create the HiRDB file system area using the pdfmkfs command, specify the maximum number of extensions (in the -e option).
3. When you create the RDAREA, use a utility control statement^# to specify the number of segments by which the RDAREA can be extended.

#

This can be specified in the CREATE RDAREA, EXPAND RDAREA, INITIALIZE RDAREA, or ALTER RDAREA statement of the database initialization utility, the database structure modification utility, or the registry facility initialization utility.