Release 10.1A: OpenEdge Data Management:
Database Administration

> ## RFUTIL AIMAGE TRUNCATE qualifier

> Truncates all of the variable-length AI`` extents and optionally sets the AI block size with the After-image Block Size (-`aiblocksize`) parameter.

> #### Syntax

>     rfutil db-name -C aimage truncate -aiblocksize size

> #### Parameters

> ``db-name``

> Specifies the database you are using.

> `-aiblocksize `size``

> Specifies the size of the AI blocks in each buffer, in kilobytes. The valid values are 1, 2, 4, 8, and 16. The block size cannot be smaller than the database block size.

> #### Notes

> - After executing this command to change the AI block size, you must perform a full backup of the database before you can re-enable after-imaging. If you change the BI block size or cluster size before backing up the database, the block size of the backup will overwrite the changed block size when the backup is restored.

> - Increasing the AI block size allows larger AI reads and writes. This can reduce I/O rates on disks where the AI areas are located. If your operating system can benefit from larger writes, this option can improve performance. Larger AI block size might also improve performance for roll-forward recovery processing.

> - When you execute this command, after-imaging and two-phase commit must be disabled, and the database must be offline; otherwise, RFUTIL returns an error message.

> - After you change the AI block size, RFUTIL uses the new block size in all database operations.

> - Use the PROSTRCT STATISTICS qualifier to display the block sizes for a database.

> - Typically, if you change the AI block size, you should also change the before-image (BI) block and cluster size; otherwise, the increased AI performance will cause a BI bottleneck.

> - See Chapter 13, "Managing Performance," for more information about using the RFUTIL AIMAGE TRUNCATE utility.

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