SQL/MP Installation and Management Guide

Enhancing Performance
HP NonStop SQL/MP Installation and Management Guide—523353-004
14-5
Avoiding Contention Between DDL Operations
DELETE, INSERT, and UPDATE access during the operation. The time difference
depends largely on the number and length of transactions on the nodes that
contain source and target objects for the operation, particularly the number and
length of transactions that directly involve source objects for the operation.
•
You cannot use the WITH SHARED ACCESS option if one or more of these
situations exist:
°
The statement executes within a user-defined TMF transaction.
°
Source objects are not audited.
°
Source or target objects reside on a node running a version older than 315 of
SQL/MP software.
°
Source objects reside on a node running TMF software released before the
D30 RVU.
°
Source or target objects reside on a node running system software released
before the D30.00 (for move partition and serial create index operations) or
D30.02 RVU (for split partition, move boundary, merge partition, or parallel
create index operations).
Avoiding Contention Between DDL Operations
Only one DDL statement can operate on a given SQL object (or partition of an SQL
object) at a time. An error occurs if you attempt to run a DDL statement while another
process is executing a DDL statement on the same object.
The specific error depends on the statement involved and the phase of the operation at
which the conflict occurs. Common errors for this situation include:
12 File in use
40 The operation timed out
73 The table is locked
Other Operational Considerations
In general, DDL operations follow a three-part process:
1. Lock the catalog entries exclusively for the objects.
2. Open the objects, read or move data, and close the objects.
3. Lock the file labels exclusively while updating them.