FastSort Manual
Sorting From NonStop SQL/MP
FastSort Manual—429834-003
8-9
Configuring a CREATE INDEX Statement
When you create a partitioned index on a base table and specify PARALLEL
EXECUTION ON, you can use either the default configuration or a custom
configuration file. A configuration file defines attributes of record generator and sort
processes. You can specify the name of a configuration file in the PARALLEL
EXECUTION clause of a CREATE INDEX statement. If you specify no configuration
file, FastSort uses the default configuration.
Using the Default Configuration
If you specify PARALLEL EXECUTION ON and do not specify a configuration file,
SQL/MP uses the following defaults:
Default Scratch File Size Formula
Under the default configuration, SQL/MP uses the following formula to estimate scratch
file size:
NonStop SQL/MP estimates the number of records in the base table by dividing file
size by record length.
Default DEFINE Attribute Values
The default configuration for CREATE INDEX includes the following attribute values:
The default configuration is not recommended for base tables with many remote
partitions. Note that in this configuration, all record generator processes that read
remote partitions swap to the same volume. When multiple processes swap to the
Attribute Default value
PRI For both RECGEN and SORTPROG, the priority of the process that
creates the index.
CPU For local partitions, the CPU that runs the primary disk process for that
partition. If a partition is remote or a CPU is unavailable, FastSort
arbitrarily selects the first CPU, then selects subsequent CPUs in a
sequential fashion. Note that multiple RECGENs or SORTPROGs can
run in a single CPU.
SCRATCH FastSort selects a volume for the initial SORTPROG scratch file.
RECGEN processes do not use scratch files.
SWAP For SORTPROGs, the scratch volume if that volume is local and if not,
the volume where the SORTPROG is running. For RECGENs, the
volume of the partition being read if that partition is local and if not, the
swap volume specified in the =_SORT_DEFAULTS DEFINE.
3
NumberofBaseTableRecords
NumberofIndexTablePartitions
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