NonStop SQL/MP Reference Manual

Table Of Contents
NonStop SQL/MP Reference Manual142115
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Considerations—=_SORT_DEFAULTS
=_SORT_DEFAULTS affects sorts performed as part of an SQL statement executed in
parallel if you do not specify scratch and swap files in a configuration file or by some
other mechanism. In this case, SQL uses the scratch and swap files specified in the
=_SORT_DEFAULTS DEFINE.
param value
specifies a FastSort parameter and a value for that parameter. The following are
some FastSort parameters commonly used in conjunction with NonStop SQL/MP:
See the FastSort Manual for information about other FastSort parameters and for
more information about the parameters just described.
Considerations=_SORT_DEFAULTS
By using =_SORT_DEFAULTS, you can improve performance for DML operations
by giving the FastSort process sufficient space for sorting on an alternate disk
ADD DEFINE =_SORT_DEFAULTS,
CLASS SORT [ , param value ] ...
param value is:
{ BLOCK block-size }
{ CPU cpu-number }
{ CPUS subsort-cpu-list }
{ MODE mode-type }
{ NOSCRATCHON ( volume-list ) }
{ NOTCPUS cpu-list-not-subsort }
{ PRI process-priority }
{ PROGRAM file }
{ SCRATCH file }
{ SCRATCHON ( volume-list ) }
{ SEGMENT extended-segment-size }
{ SUBSORTS define-list }
{ SWAP file-name }
{ VLM { ON | OFF } }
SCRATCH file specifies the Guardian name of a scratch file or volume to
store runs of records sorted by each SORTPROG process.
If you specify only a volume name, FastSort automatically
creates the scratch file; this method is recommended for
parallel sort operations.
SWAP file specifies the Guardian name of a swap file or volume for
the extended memory segment. If you specify only a
volume name, FastSort automatically creates the swap file;
this method is recommended for parallel sort operations.
VLM { ON | OFF } specifies use of additional memory for sorting; improves
performance in certain situations (usually for LOAD, but
not for CREATE INDEX). Do not use VLM for parallel
sort operations.