How to reintroduce a page set
In certain scenarios it is useful to be able to bring an old page set online
again to the queue manager. Unless specific action is taken, when the old
page set is brought online the queue manager will recognize that the page
set recovery RBA stored in the page set itself and in the checkpoint records
is old, and will therefore automatically start media recovery of the page
set to bring it up to date.
Such media recovery can only be performed at queue manager restart, and
is likely to take a considerable length of time, especially if archive logs
held on tape must be read. However, normally in this circumstance, the page
set has been offline for the intervening period and so the log contains no
information pertinent to the page set recovery.
The following three choices are available:
- Allow full media recovery to be performed.
-
- Stop the queue manager.
- Ensure definitions are available for the page set in both the started
task procedure for the queue manager and in the CSQINP1 initialization data
set.
- Restart the queue manager.
- Allow any messages on the page set to be destroyed.
- This choice is useful where a page set has been offline for a long time
(some months, for example) and it has now been decided to reuse it for a different
purpose.
- Format the page set using the FORMAT function of CSQUTIL with the TYPE(NEW)
option.
- Add definitions for the page set to both the started task procedure for
the queue manager and the CSQINP1 initialization data set.
- Restart the queue manager.
Using the TYPE(NEW) option for formatting clears the current contents
of the page set and tells the queue manager to ignore any historical information
in the checkpoint about the page set.
- Bring the page set online avoiding the media recovery process.
- Use this technique only if you are sure that the page set has been offline
since a clean shutdown of the queue manager. This choice is most appropriate
where the page set has been offline for a short period, typically due to operational
issues such as a backup running while the queue manager is being started.
- Format the page set using the FORMAT function of CSQUTIL with the TYPE(REPLACE)
option.
- Either add the page set back into the queue manager dynamically using
the DEFINE PSID command with the DSN option or allow it to be added at a queue
manager restart.
Using the TYPE(REPLACE) option for formatting checks that the page set
was cleanly closed by the queue manager, and marks it so that media recovery
will not be performed. No other changes are made to the contents of the page
set.