Manage Transaction Rollback Using Manage^JRNROLL
InterSystems IRIS provides the ^JRNROLL utility to roll back partially completed transactions for records in the journal; use the Manage entry point (Manage^JRNROLL) when transaction rollbacks are pending or in progress at system startup or primary mirror member startup.
To start managing transaction rollback, run Manage^JRNROLL or enter 11 at the Option prompt of the ^JOURNAL menu, as shown in the following example:
%SYS>Do ^JOURNAL
...
11) Manage pending or in progress transaction rollback (Manage^JRNROLL)
...
Option? 11
Choosing option 11) Manage pending or in progress transaction rollback (Manage^JRNROLL) displays a message similar to the following:
Transaction rollback is pending or in progress
Do you wish to run Manage^JRNROLL? Yes => Yes
Rollback operations currently in progress
ID Phase MB Remaining Current Open Transaction Count
1 scan 307 2
Rollback at system startup at 11/29/2023 15:54:35 (578MB)
20231129.004 has 2 open transaction(s) starting at offset 11303
2 file(s) remaining to process
1) Restart pending rollback
2) Interrupt transaction rollback
3) Redisplay rollback information
4) Discard pending rollback
Option?
This option displays the state of transaction rollbacks, including what phase (scanning or rollback) it is in, the amount of data (MBs) remaining to be processed, the number of open transactions it has found, etc.
In addition, it lists suboptions that let you manage the listed transaction rollbacks. For example, you can interrupt the operation, in which case it is queued as a “pending” operation; then you can restart pending rollbacks.
Caution:
Option 4) Discard pending rollback is not reversible; do not use it unless you are certain you want to permanently discard the pending rollback.
Note:
On a mirror, transaction rollback is executed twice: once for nonmirrored databases (at system startup); then for mirrored databases (when a system becomes the primary mirror member). As a result, when starting the primary mirror member, it may be necessary to interrupt the rollback twice, resulting in two pending operations. Restarting the pending operations performs the non-mirror and mirror rollbacks separately.
During rollback, messages are written to the messages log (messages.log) every 10% of the way through (more or less) indicating how much space is left to process and how many open transactions are listed.
When journal files are purged, files required for pending transaction rollback are retained (for example, if they would otherwise have been deleted).
