SQL/MX 2.x Installation and Management Guide (G06.24+, H06.03+)

Reorganizing SQL/MX Tables and Maintaining Data
HP NonStop SQL/MX Installation and Management Guide—523723-004
10-24
Other import Features
Other import Features
•
import automatically turns auditing off for all partitions of an empty table without
indexes. Auditing is turned back on after the import operation completes or if it
fails for any reason. This enables import to take advantage of fast loading
techniques and to avoid TMF transaction issues. Turning off auditing for a table
invalidates online dumps. After the import operation completes, you must take a
new TMF online dump for all partitions on the table. For more information, see
Running import on Empty Tables on page 10-25.
To improve the performance of the fast 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 load 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.
•
The ability to specify the first row to import from the input file where the first row
is designated 0.
•
The validity of imported binary values for NUMERIC, DECIMAL, FLOAT, TIME,
TIMESTAMP, and DATE types are not checked. You should make sure that the all
binary values fall within the range of values supported by the data type.
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 10-25
•
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 10-27
•
Managing Triggers to Improve import Performance on page 10-28
•
Managing Data Types to Improve import Performance on page 10-28