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
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Using import to Append Data to Tables or Partitions
Guidelines for Appending Data to Tables
•
Use the import command to add data to a table or partition without purging
existing data.
•
Use import to add data to SQL/MX tables. You cannot use import to add data
to ASCII files or any other files other than SQL/MX tables.
•
import can use ASCII source files or input files from DataLoader/MX.
•
Use import to insert data into an audited table without resetting the audit
attribute.
•
If an error occurs during an append operation and import is able to terminate
gracefully, no new data is added to the target table for the last transaction run. To
determine if an append operation succeeded, check the listing to see if error
messages occurred.
•
If a CPU failure, process failure, BREAK command, or event interrupts an import
operation, import terminates with the table still in a valid state. Rows are
committed based on the -T option if that option is specified. For more information
about import, see the SQL/MX Reference Manual.
Appending Data to Multiple Partitions in Parallel
Use import to append data to partitioned tables in parallel. This strategy can improve
append performance if table partitions are distributed across disks, CPUs, and I/O
channels. To append data to partitions in parallel:
1. Start an import process for each partition. One way is to start each import
process in the CPU associated with the target partition. Another way is to start
import processes in the CPUs associated with the data sources for the import
command.
2. Issue one import request for each table partition.
3. Supply each import command with the specific range of input data for the target
partition. Possible strategies are:
•
Arrange the input data so that it is divided into separate files, each containing
input for a specific target partition. Use these files as input to import
commands.
•
Run one instance of the import command to load data into a partitioned table
by using a single input file.
•
Use DataLoader/MX to read input data. Start each DataLoader/MX process as
a named process before entering the import command. Use the process
name as the input file for the import command. The DataLoader/MX process
must wait for requests on its $RECEIVE file and then supply data by replying to
those requests. When using this approach, be sure to balance processing for
optimal performance.