Controlling Page Size and the Number of Buffers
Measuring I/O
Improvement
in I/O can come at the cost of increased memory consumption. In order
to understand the relationship between I/O and memory, it is helpful
to know when data is copied to a buffer and where I/O is measured.
When you create a SAS data set using a DATA step, the following actions
occur:
-
SAS copies a page of data from the input data set to a buffer in memory.
-
One observation at a time is loaded from the buffer into the program data vector.
-
Each observation is written from the PDV to an output buffer.
-
The contents of the output buffer are written to the disk when the buffer is full.
The process for reading external files is similar. However, each ...
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