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
10-25
Recommended Practices for Improving import
Performance
To improve the performance of the fasting load technique, import turns off the audit
attribute for the entire table at the start of the operation and turns it back on when the
operation ends. If another import operation is attempted on the same table while an
import operation with the fast loading technique is being performed, the second
operation fails with a concurrent access error. For more information, see the SQL/MX
Reference Manual.
If the table is not empty or has dependent indexes, import continues with the normal
load operation using TMF transactions.
For more information about import command features and options, see the SQL/MX
Reference Manual.
Recommended Practices for Improving import Performance
This subsection describes recommended practices for improving the performance of
import operations on SQL/MX tables:
•
Running import on Empty Tables on page 10-25
•
Running import on Populated Tables on page 10-26
•
Managing Partitions to Improve import Performance on page 10-26
•
Managing Constraints to Improve import Performance on page 10-27
•
Managing Indexes to Improve import Performance on page 10-28
•
Managing Triggers to Improve import Performance on page 10-28
•
Managing Data Types to Improve import Performance on page 10-28
Running import on Empty Tables
You can import data into a table most quickly by using the fast loading technique,
which import automatically uses when the table meets all these conditions and no
transaction size is specified on the import command line:
•
It is empty.
•
It has no indexes.
•
It has no droppable primary key, unique key, or foreign key constraints.
•
It has no enabled triggers.
To further improve the performance of the fast loading technique, import turns off
the audit attribute for the entire table at the start of the operation and turns it back on
when the operation ends.
If, while you are performing an import operation with the fast loading technique,
another import operation is attempted on the same table, the second operation fails
with a concurrent access error.
To improve the performance of an import operation on an empty table: