Determine the extended segment count so that automatic extension does not occur frequently during a single job.

Even when RDAREA automatic extension is applied, it might be suppressed in some cases. The following table shows the causes of this suppression and the main corrective actions that can be taken.

Table 15-5 Causes of RDAREA automatic extension suppression and the main corrective actions that can be taken

Cause	Main corrective action
A space shortage has occurred on the disk on which the HiRDB file system area was created.	Perform the following corrective procedure: Check the disk capacity and increase if necessary. Use the database reorganization utility (pdrorg command) to reorganize the tables and indexes. Use the expand rdarea statement of the database structure modification utility (pdmod command) to expand the RDAREA. If a HiRDB file system area of an RDAREA to which automatic extension is applied is a regular file, set the OS system resource limitation value for the HiRDB administrator and the root user to a value greater than the size of the HiRDB file system area, or set it to an unlimited value.
The RDAREA is in updatable backup hold status or updatable backup hold status (WAIT mode).#	Use the pdrels command to release the RDAREA from shutdown status.
The RDAREA is located in the main memory.	Synchronize the in-memory data buffer with the RDAREA, and then release the RDAREA from the in-memory configuration. For details, see the manual HiRDB Version 9 Batch Job Accelerator.
The last HiRDB file in the user LOB RDAREA is in frozen update status.	Perform the following corrective procedure: Use the expand rdarea statement of the database structure modification utility (pdmod command) to expand the RDAREA. Execute the pddbfrz -d command to release the HiRDB file from frozen update status.

#

When an RDAREA is in updatable backup hold status or updatable backup hold status (WAIT mode), RDAREA automatic extension is suppressed. For this reason, while an RDAREA is in either of these statuses, refrain from executing a job that adds or updates a large volume of data, thus requiring allocation of new pages. However, if use is specified for the pd_rdarea_extension_timing operand, you can use the free segments (extended segment count) until data addition causes a page shortage even when RDAREA automatic extension is suppressed because the RDAREA is in updatable backup hold status. Therefore, the impact on jobs can be reduced compared to a case in which nouse is specified for the pd_rdarea_extension_timing operand.

While an RDAREA is being automatically extended, the last HiRDB file in the RDAREA is locked. Consequently, any transaction that updates (or adds data to) a table or index in the RDAREA being automatically extended goes into wait status. Furthermore, if the setting that initializes the HiRDB file system area during automatic extension is used (if Y is specified for the pd_rdarea_expand_format operand), the initialization causes input/output operations, lengthening the transaction execution time accordingly. These causes might result in the transaction being canceled for one of the following reasons:

• The lock-release wait time has been exceeded.
• A HiRDB client's maximum wait time or a utility's maximum execution time has been exceeded.

Therefore, if the items listed below are being monitored, set the limit value by considering the time required for automatic extension based on the RDAREA configuration information (page size, segment size, and the extended segment count) and the input/output performance of the disk on which the HiRDB file system area is located.

• The lock-release wait time (the pd_lck_wait_timeout operand in the system common definition)
• Operands and options described in 8.10 Monitoring the execution time of UAPs and utilities (reducing the effects of nonresponding programs)

Use the following formula to estimate the time required for automatic extension (in seconds):

applicable RDAREA page size (A extended segment count + B) C

A: Segment size if the HiRDB file system area is to be initialized during automatic extension, 0 otherwise

B: Number of directory pages to be created during automatic extension

• For a data dictionary RDAREA, user RDAREA, or registry RDAREA
  extended segment count b + extended segment count f
  b: page size - 20 (segment size 32 8 + 56)
  f: (125 page size) (16 b) b
  
• For a LOB RDAREA
  segment size 64,000 96
  

C: Input/output performance of the disk on which the HiRDB file system area was created (the number of input/output bytes per second)

When the hybrid method is used for Real Time SAN Replication, HiRDB waits for the database to be synchronized with the remote site when RDAREA automatic extension occurs. For this reason, an extension operation might result in a processing overhead of 2 seconds or longer.