34.5.1 Common notes

1. The adbmodarea command cannot be executed concurrently with any other application program or command.

2. A block special file that has already been allocated to a DB area file cannot be allocated as a new data DB area file.

3. Data DB area files cannot be created in a file system that does not support direct I/O.

4. In case you need to restore a DB area that was deleted by mistake, make sure that you make a backup of the database before you delete DB areas. For details about backups, see Backing up a database in the HADB Setup and Operation Guide.

5. When the adbmodarea command overwrites an existing file, it first deletes the target file, and then re-creates the file.

6. If the adbmodarea command terminates abnormally, eliminate the cause of the error, and then re-execute the command.

7. If the HADB terminates abnormally due to, for example, power outage during execution of the adbmodarea command, rollback might fail, causing the database to be placed in an invalid state. In such a case, execute the adbstart command to restart the HADB server.

8. If the HADB terminates abnormally due to, for example, power outage during execution of the adbmodarea command, unnecessary DB area files might remain. However, because remaining DB area files do not cause problems, you do not need to delete them.

   If you want to delete the remaining DB area files, use the following procedure:

   Step 1

   Execute the adbstart command to restart the HADB server. You cannot delete DB area files until the HADB server has restarted.

   Step 2

   Execute the adbdbstatus command with used specified for the -d option.

   Step 3

   Make sure that the DB area files you want to delete are not displayed in the DBarea_filename column in the usage information for DB areas, tables, and indexes output by the adbdbstatus command.

   DB area files not being used by the HADB server are not output to the DBarea_filename columns. Therefore, you can determine that those DB area files can be deleted. However, some files (such as ADBMST) that are not displayed in the DBarea_filename column might be used by the HADB server. Do not delete applicable files (such as ADBMST).

   Step 4

   Make sure that the HADB server is not using the DB area files you want to delete, and then delete them by using the OS's rm command or the like.

9. If the HADB server terminates abnormally due to, for example, power outage during execution of the adbmodarea command, a message indicating the processing results in the HADB server might not be output. If no message was output, restart the HADB server that terminated abnormally, and then execute the adbdbstatus command. From the output results of the adbdbstatus command, you can determine whether the changes of DB areas have been applied.

10. A global buffer is allocated automatically for a data DB area that is added by the adbmodarea command. If you want to allocate a specific buffer, specify the adbbuff operand in the server definition, and then restart the HADB server. For details about how to specify the adbbuff operand, see the topic Operands and options related to global buffers (command format) in Detailed descriptions of the server definition operands in Designing the Server Definition in the HADB Setup and Operation Guide.

11. If all data DB areas for which a global buffer has been allocated are deleted, the shared memory that was used by the global buffer is released.

12. When DB areas are added or deleted, the memory requirements listed below change; so, in such cases, re-estimate the memory requirements. For details about how to determine the variables, see the topic Determining the memory requirement for starting the HADB server in Estimating the HADB server's memory requirement in Preparing Resources in the HADB Setup and Operation Guide.

    • Memory size required for global buffer pages (SHM_BUFGLOBAL variable)

    • Required process common memory size (BUFGLOBAL variable)

13. If using SCSI reservation for shared disk for a cold standby configuration, you need to change the operand specified in the servers file for HA Monitor when you perform one of the following operations:

    • Adding a DB area by using the adbmodarea command

    • Expanding a DB area by using the adbmodarea command

    • Deleting a DB area by using the adbmodarea command

    Therefore, you need to terminate the cold standby configuration. For details about the operation procedure, see Adding, deleting, or expanding data DB areas (in the case of the cold standby configuration) in the HADB Setup and Operation Guide.

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