SQL/MX 2.x Installation and Management Guide (H06.04+)

Reorganizing SQL/MX Tables and Maintaining Data
HP NonStop SQL/MX Installation and Management Guide—540436-001
10-6
Consequences of a Failed Utility Operation
•
A DDL operation that changes the definition of the object (for example, alter table,
add column, or create index)
•
A DDL operation on a dependent object (for example, an index, constraint, or
trigger)
•
A utility operation that changes the definition of the object
•
A utility operation on a dependent object
These SQL/MX utilities use DDL locks:
•
MODIFY. See Using MODIFY to Manage Table and Index Partitions on
page 10-10.
•
import (for the fast loading option only). See Using import to Load SQL/MX
Tables on page 10-22.
•
POPULATE INDEX
•
DUP. See Using DUP to Copy Tables Into Tables on page 10-35.
•
PURGEDATA. See Using PURGEDATA to Delete Data From Tables on
page 10-37.
A DDL lock is obtained when any of these utilities starts. When the utility operation
completes, the DDL lock is removed. While the DDL lock exists, other structure
changing operations cannot be run.
A utility that holds a DDL lock can terminate without removing the DDL lock. For
example, suppose that a resource on which a utility operation is running becomes
unavailable, causing the MXCMP process and the utility to fail. Because the DDL lock
is persistent, it still exists after the operation fails as an inactive DDL lock. If a utility
operation fails and an inactive DDL lock is present, you must perform a RECOVER
operation on the affected SQL/MX object to restore the utility operation to a known
good state.
Consequences of a Failed Utility Operation
If a failure, such as an unavailable resource or TMF failure, prevents a utility operation
from completing successfully, the utility responds by attempting to perform its own
internal recovery procedure for the purpose of completing the request or, if necessary,
rolling back the operation to the known good state from which it began.
The utility’s own recovery procedure can fail because of circumstances beyond its
control. For example, the utility’s recovery procedure might fail because TMF is down.
If the utility’s own recovery procedure is unable to complete or roll back the failed utility
operation, the utility operation returns an error. You can use this error information to
isolate the cause for the failure and ensure that it is corrected.