![]() Where UNIX-command is any command that generates a stream of data that is understandable as an input file to sas. The FILENAME statement can assign a fileref to any unix pipe with the syntax: FILENAME fileref PIPE 'UNIX-command' This is applicable only to SAS on Unix/Linux systems.Įxternal tools can be used to decompress data files into a pipe (in-memory transfer between processes) and then SAS can read from the pipe. SAS reference: /documentation/ The PIPE input mechanism The SAS output listing reports on the space savings of using COMPRESS. The reference above suggests that it can make a big difference, and has improved in efficiency with newer SAS versions. ![]() Both operate at the level of individual records and so work best on datasets with large records. " COMPRESS=char", which compresses character variables with run-length encoding (generally not very useful), and " COMPRESS=binary" which performs a more advanced compression scheme on repeated groups of characters. The effectiveness of this option depends greatly on the data. The COMPRESS= option in DATA statements can be used to reduce the size of datasets (. It also has examples of the COMPRESS option. This paper sugi27/p023-27.pdf has good general advice on reducing the memory usage and processing time for large datasets by removing unwanted variables. Saving memory and I/O and disk space in SAS datasets by eliminating variables that you won't use, as early as possible in the processing (e.g. These notes describe four ways to reduce the size of SAS datasets and deal with compressed input files. Using compressed data files may result in higher performance, especially if network file storage is in use, since the reduced I/O more than compensates for the CPU effort needed to decompress. External data files to be read by SAS (.e.g CSV or formatted text files) may be very large and also compress well, but SAS must be instructed how to read them. They compress very well with any of the standard lossless file compression tools ( zip, gzip, bzip2 etc.), but cannot be used by SAS in that form. sas7bdat files) are generally inefficient on disk space, since they reserve space for the maximum size of all variables, including missing data.
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