onunload,onload.
These utilities are useful in several ways:
They provide fast table level backups.
They provide fast database level backups.
When transferring tables or databases to other systems with different dbspace layouts.
When moving databases or tables from one dbspace to another.
onunload onload is faster than dbexport including existing indexes structures.
This makes it very fast to reload because indexes do not need to be rebuilt.
Also, since the output is stored in binary format, there is some security in the data being protected.
There are a few drawbacks to these two utilities:
Data is not portable. It can only be loaded using the same version of OnLine on the same type of machine. Since the data is stored in binary format the operations need to be performed on computers that are binary compatible.
Data is not compressed. Since the data is copied in whole pages, empty data space and empty index structures on a
page remain and are reloaded on the target system. SQL unload and load will rebuild the data on pages and rebuild all indexes compressing the data.
The utilities will require an exclusive lock on the table or database being unloaded and loaded.
If you need to unload data in ASCII or text format use the SQL unload statement of DBEXPORT.
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