NOSYNC Considerations - TARA/ABU

Teradata Archive/Recovery Utility Reference

Product
TARA/ABU
Release Number
16.10
Published
May 2017
Language
English (United States)
Last Update
2018-05-01
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B035-2412
lifecycle
previous
Product Category
Teradata Tools and Utilities

The NOSYNC option tells Teradata ARC to handle lock conflicts in a special way. Without the NOSYNC option, Teradata ARC is blocked when a table it attempts to lock is already locked by a different process. There is no indication that a lock is blocking Teradata ARC, it simply appears that Teradata ARC is in a hanging state.

If NOSYNC is specified, Teradata ARC will not initially block on those tables that are already locked by a different process. Instead, Teradata ARC will retain control and display the following message:

"Unable to enable Online Logging on %s tables due to lock conflicts."

If the VB3 runtime parameter is specified, Teradata ARC will follow the above message with a list of tables that are blocked by an existing lock.

After reporting the lock conflict(s), Teradata ARC will retry each blocked Online Log request, one table at a time, displaying the following message for each table as it does so:

"Retrying Online Log request for table '%s' - waiting to obtain lock."

This time, Teradata ARC will block if the lock is still owned by another process until the lock is freed up and Teradata ARC can obtain it. When Teradata ARC can obtain the lock and thereafter enable Online Logging on that table, Teradata ARC displays the following message:

"Retry of Online Log request for table '%s' was successful."

After Teradata ARC successfully enables Online Logging on a blocked table, it continues with the next table until it has successfully enabled Online Logging on all of the blocked tables. The Archive process does not start until Teradata ARC has successfully enabled Online Logging on all of the involved tables.

By using this methodology, Teradata ARC can let the user know which table it is currently blocked on. This allows the user to decide whether it is desirable to make any changes which could free up that lock, so that Teradata ARC can continue.

All objects in the initial request to enable Online Logging will have the same consistency point, except for those table(s) that were blocked by a lock. Each of the blocked table(s) will have a different consistency point as those tables are retried with a separate Online Logging request, one at a time.