SAS library write speed test macro

The `%mp_testwritespeedlibrary` macro is designed to benchmark write performance in a SAS^© library. It takes as parameters the target library (`lib`), the file size to create in GB (`size`), and the output dataset (`outds`) for the results. The macro generates a unique dataset name to avoid conflicts, creates a temporary dataset of the requested size by writing a calculated number of observations, records the start and end timestamps of the operation, then deletes the temporary dataset. Finally, it records the test details (library, start/end time, duration) in the specified output dataset.

Data Analysis

Type : CREATION_INTERNE

Data is dynamically generated by a `DATA STEP` within the macro (`do x=1 to size; output; end;`) to create a dataset of the specified size. No external data or data from SASHELP is used for the content of the tested dataset.

1 Code Block

Macro definition and initialization

Explanation :
This block defines the `%mp_testwritespeedlibrary` macro with its parameters and their default values. It declares the local macro variables `ds` (for the temporary dataset name) and `start` (for the start timestamp). It uses a `%do %until` loop with the `%mf_getuniquename()` and `%mf_existds()` macros to generate a unique dataset name that does not yet exist in the specified library, ensuring no conflicts. Finally, it captures the operation's start time via `%sysfunc(datetime())`.

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1	%macro mp_testwritespeedlibrary(lib=WORK
2	,outds=work.results
3	,size=0.1
4	)//STORE SOURCE/;
5	%local ds start;
6
7	/* find an unused, unique name for the new table */
8	%let ds=%mf_getuniquename();
9	%DO %until(%mf_existds(&lib..&ds)=0);
10	%let ds=%mf_getuniquename();
11	%END;
12
13	%let start=%sysfunc(datetime());

2 Code Block

DATA STEP Data

Explanation :
This `DATA STEP` is the core of the performance measurement. It creates a dataset named `&lib..&ds` (the previously generated unique name) without compression (`compress=no`) and retaining only column `x` (`keep=x`). The `size` variable is calculated to determine the number of observations needed to reach the target size specified by the macro's `size` parameter (converted from GB to bytes and adjusted for a 'header'). The loop `do x=1 to size; output; end;` generates observations, thus simulating a significant write load.

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1	DATA &lib..&ds(compress=no keep=x);
2	header=128*1024;
3	size=(1073741824/8 * &size) - header;
4	DO x=1 to size;
5	OUTPUT;
6	END;
7	RUN;

3 Code Block

PROC SQL

Explanation :
This `PROC SQL` block executes a `DROP TABLE` statement to delete the temporary dataset `&lib..&ds` created previously. This is an essential cleanup step to prevent library clutter and ensure that tests are reproducible without residues from previous operations.

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1	PROC SQL;
2	drop TABLE &lib..&ds;
3	RUN;

4 Code Block

DATA STEP Data

Explanation :
This `DATA STEP` creates the final `&outds` dataset, which contains the performance test results. It records the library name (`lib`), the start time (`start_dttm`), and the end time (`end_dttm`) of the write operation (formatted as `datetime19.`). The `duration_seconds` is calculated by subtracting the start time from the end time, providing a direct measure of write speed.

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1	DATA &outds;
2	lib="&lib";
3	start_dttm=put(&start,datetime19.);
4	end_dttm=put(datetime(),datetime19.);
5	duration_seconds=end_dttm-start_dttm;
6	RUN;

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Copyright Info : Copyright (c) 2001-2006 Rodney Sparapani (from `_version.sas`), licensed under GNU General Public License. The macro's HELP block also references 'Copyright 2010-2023 HMS Analytical Software GmbH'.

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