After-image sequences
- Last Updated: January 16, 2024
- 1 minute read
- OpenEdge
- Version 12.8
- Documentation
After-image sequences
The SEQUENCE qualifier to the RFUTIL utility provides database administrators the ability to update after-image sequence numbers and improves your ability to maintain a hot standby database recovery strategy.
RFUTIL SEQUENCE updates the sequence number of your hot standby target database to match the sequence number of the AI extent that was BUSY at the time the source database was copied to create the hot standby.
After executing RFUTIL SEQUENCE on your standby target database, you can keep the target in sync with the source by rolling forward AI extents, starting with the extent that was BUSY when the copy occurred.
See RFUTIL SEQUENCE qualifier for the command syntax.
A hot standby is typically maintained by first making a copy
of your source database, and then regularly updating the database
by rolling forward the AI extents from the source
to the target. The preferred methods of making a copy of your database
use the OpenEdge utilities PROCOPY or PROBKUP. However, if you
use your operating system commands to make a copy, the SEQUENCE
qualifier to RFUTIL is available to update your target database
to expect the correct after-image extent in the roll forward sequence.
Correcting the sequence is only necessary if there has been an AI extent
switch on your source database after the database was last
marked as backed up and before the operating system copy
was made.