SQL/MP Installation and Management Guide

Reorganizing Tables and Maintaining Data
HP NonStop SQL/MP Installation and Management Guide—523353-004
8-3
Reorganizing Key-Sequenced Files
Before performing a RELOAD operation, consider these issues:
•
The file must be key-sequenced.
•
The operation can cause degraded performance. You can, however, control the
amount of degradation by using the command’s RATE option. The higher the rate,
the faster the reload occurs, but the more performance degrades. Conversely, the
lower the rate, the slower the reload occurs, but the less performance degrades.
The default value for RATE is 100 percent.
•
For tables audited by the TMF subsystem, the operation generates audit-trail
records describing the movement of data within the file. The total amount of audit-
trail data generated for any given file cannot be calculated exactly. For a large file
with a lot of data movement, however, the amount can be two to three times the
total number of rows in the table. For this reason, the parameters governing the
use of TMF audit trails might need to be increased to accommodate the audit-trail
data. Or, as a more convenient alternative to increasing these parameters, you
might want to increase the frequency of the audit-trail dumps. For more
information, see the TMF Operations and Recovery Guide.
•
The RELOAD command reorganizes either a table or an index independent of
each other.
•
Three RELOAD parameters control block slack:
°
DSLACK controls the amount of free space in a table’s data blocks. The default
value for this parameter is 15 percent.
°
ISLACK controls the amount of free space in a table’s index blocks. The
default value for this parameter is 15 percent.
°
SLACK controls the amount of free space in both index and data blocks. The
default value for this parameter is 15 percent.
•
When the RELOAD command is issued, FUP initiates a background process to
perform the operations requested by the command. After the process is initiated,
FUP displays the message RELOAD STARTED and either returns a prompt or
terminates (depending upon whether FUP was initiated interactively or
noninteractively).
•
The RELOAD operation might take a long time, depending upon the size of the file
and the rate specified for the command.
•
You can suspend the RELOAD operation or request a status report about the
progress of the operation, as explained in the next subsection, Determining the
Status of a Reorganization.
This command initiates a RELOAD operation for the table named CUSTOMER. The
SLACK option sets a minimum amount of free space in the blocks.
13> FUP
- RELOAD $VOL.SALES.CUSTOMER, RATE 30, SLACK 50