@ciaran2  - No I don't have any experiences to share regarding multi-threading. Have you read the paper linked above? Most DS2 multi-threaded examples tried were slower than a single-threaded version.   In my experience minimising and tuning IO results in significant performance improvements. Also if you really want to speed up a SAS application, parallel processing, if appropriate, can reduce processing time massively. I have one parallel processing job that originally took over 14 hours to run and now takes under 4 hours. The nice thing about parallel processing is you don't need to recode you just split it into separate SAS sessions.   ... View more

Maybe it depends on the server settings, but on my machine this code works :). I have SAS 9.4.6. NOTE: Variable COUNT is uninitialized. NOTE: The data set WORK.TABLE_OUTPUT has 4 observations and 2 variables. NOTE: There were 10 observations read from the data set WORK.TABLE_INPUT. Table table_output: X    COUNT 2    1 3    2 4    2 7    5 In the output I have the number of observations X in the table_input set. ... View more