| Date: | Tue, 16 Apr 2002 12:53:58 -0700 |
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| Reply-To: | "Wagner, Eric J. (V15)" <Eric.Wagner@MED.VA.GOV> |
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| Sender: | "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU> |
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| From: | "Wagner, Eric J. (V15)" <Eric.Wagner@MED.VA.GOV> |
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| Subject: | Proc merge data set order |
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| Content-Type: | text/plain; charset="iso-8859-1" |
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Greetings,
When performing a PROC MERGE, where one dataset is much larger than the
other, is it faster to list the large dataset first or second? I am trying
to minimize CPU cycles used and execution time. For example:
DATA combined;
MERGE IN1.SUMMARY (IN=A keep=fundgrp scrssn ) IN6.SSN (IN=B);
By ssn;
RUN;
or
DATA combined;
MERGE IN6.SCRSSN (IN=B) IN1.SUMMARY (IN=A keep=fundgrp scrssn );
By ssn;
RUN;
where IN1.SUMMARY is on the order of 1GB in size and IN6.SSN is about 200k.
Thank you,
Eric Wagner
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