11.18.4 Cases where the updated-row columnizing facility must be disabled temporarily
Temporarily disable the updated-row columnizing facility in the following cases:
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When creating a backup
When data in row store format is converted to column store format by the updated-row columnizing facility, a database update occurs. If you do not want the database to be updated while you are creating a backup, temporarily disable the updated-row columnizing facility.
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When you want to have no impact on the execution time of an SQL statement or command
If the updated-row columnizing facility is enabled, the execution time of an SQL statement or command might be adversely affected slightly (by about 0.5 seconds). To have no impact on the execution time, temporarily disable the updated-row columnizing facility.
For example, in the following cases, consider whether the updated-row columnizing facility is to be disabled:
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When you execute an SQL statement or command that ends in a short time (a few seconds to a few minutes) and you think that the facility greatly affects the execution time)
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When you execute an SQL statement or command whose execution time must not be affected
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When you perform batch processing or other processing that must be completed in a predefined time period
- Note
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A command in this context refers to a command that connects to the HADB server.
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A 0.5-second slowdown is indicated only as a guide. The actual slowdown time differs depending on the condition under which the processing runs. If an SQL statement or command is executed while the maintenance processing is in progress, the maintenance processing is interrupted, and execution of the SQL statement or command also stops until the maintenance processing starts again. This takes about 0.5 seconds.
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If a hard disk rather than a flush storage device is used for the DB area or a regular file rather than a block special file is used for the DB area, it might take a few seconds or more to interrupt the maintenance processing.
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To disable the updated-row columnizing facility, execute the adbcolumnize command.
- Command execution example
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adbcolumnize --stop
Confirm that the updated-row columnizing facility is disabled as explained in 11.18.3 How to check the status of the updated-row columnizing facility (whether the facility is enabled or disabled).