The following figure shows how to use the frozen update command to make backups.

Figure 6-5 Using the frozen update command in order to make backups

Explanation

The frozen update command is executed before making backups, thereby placing HiRDB files 2 and 3 in frozen update status.

1. Back up all HiRDB files (HiRDB files 1-4) when the first backup is made.
2. Because HiRDB files 2 and 3 are in frozen update status, their contents will not change after that first backup is made. Thus, it will not be necessary to back up HiRDB files 2 and 3 when the next backup is made; only HiRDB files 1 and 4 will need to be backed up.

Remarks

Because the lead HiRDB file (HiRDB file 1 in Figure 6-5) contains management records, write transactions always occur in it even if its data portion is full. Consequently, the lead HiRDB file is never placed in frozen update status and must always be backed up.

The procedure for making a backup is described below. For an operation example, see 6.8.3 Operation example.

Procedure

1. Use the frozen update command to place the HiRDB files with full data pages in frozen update status.
2. Use the KFPH27024-I message or the database condition analysis utility (pddbst command) to check the HiRDB files that are in frozen update status.
3. Make a backup. Include all HiRDB files in the first backup. In the second and subsequent backups, include only the HiRDB files that are in permit update status; it will not be necessary to include the HiRDB files that are in frozen update status.

To release a HiRDB file from frozen update status, execute the pddbfrz -d command.

Reinitializing RDAREAs also releases frozen update status.

Execute the database condition analysis utility (the pddbst command) to check which HiRDB files are in frozen update status.

The following HiRDB files cannot be placed in frozen update status:

• HiRDB files in other than user LOB RDAREAs
• Lead HiRDB files in user LOB RDAREAs
• HiRDB files in user LOB RDAREAs that store plug-in indexes
• HiRDB files in unused user LOB RDAREAs (without any table definitions)
• HiRDB files with logical files created by data type plug-ins^#

#: In the case of user LOB RDAREAs used by data type plug-ins, HiRDB files with logical files used by plug-ins cannot be placed in frozen update status. A logical file is normally found only in the lead HiRDB file, but when expansion of the logical files occurs, a logical file might be found in a HiRDB file other than the lead file. Therefore, if you are using data type plug-ins, you should estimate the size for the lead HiRDB file so that it can store logical files for plug-ins created by CREATE TABLE.