| Data Set Options under OpenVMS |
Specifies the bucket size for a new data set.
| Default: |
32
|
| Valid in: |
DATA step and PROC steps
|
| Category: |
Data Set Control
|
| Engines: |
CONCUR
|
| OpenVMS specifics: |
All aspects are host-specific
|
-
bucket-size
-
specifies a set number of block that are
used for building and processing files of relative and indexed organization.
If you specify a value of 0, SAS uses the minimum number of blocks that are
needed to contain a single observation.
The
BKS= data set option specifies the number of OpenVMS disk
blocks in each bucket of a new data set. A disk block
is 512 bytes. A bucket is a storage structure of a set
number of blocks used for building and processing files of relative and indexed
organization. A bucket contains one or more records or record cells. Buckets
are the unit of contiguous transfer between RMS buffers and the disk.
The BKS= data set option is applied only when the data
set is created. When deciding on the bucket size to use, consider whether
the file will be accessed randomly (small bucket size), sequentially (large
bucket size), or both ways (medium bucket size). For example, if you know
that all the files in a SAS library will be accessed randomly, by using the
FSEDIT procedure for example, then use a small bucket size at the creation
of each file to optimize the access. The following example uses the BKS= option
in the LIBNAME statement so that the bucket size applies to all CONCUR data
sets in that library:
libname test concur '[randomdir]' bks=30;
The BKS= data set option corresponds to the FAB$B_BKS
field in OpenVMS RMS or to the FILE BUCKET_SIZE attribute
when you use File Definition Language (FDL). For additional details, see Guide to OpenVMS File
Applications.
Copyright © 2009 by SAS Institute Inc., Cary, NC, USA. All rights reserved.
