Date: Thu, 22 Jan 2009 17:58:18 -0600
Reply-To: Joe Matise <snoopy369@GMAIL.COM>
Sender: "SAS(r) Discussion" <SAS-L@LISTSERV.UGA.EDU>
From: Joe Matise <snoopy369@GMAIL.COM>
Subject: Re: Work Folder ??
In-Reply-To: <200901222330.n0MLW8Fv011379@malibu.cc.uga.edu>
Content-Type: text/plain; charset=ISO-8859-1
I'm highly confused by the DATA A times. They're nearly identical to the
CPU times. In my experience that's never true for writing out a significant
dataset... I/O times are always far more significant than simple processing.
Does that suggest that DATA A is writing to memory, and WORK.A is writing to
disk?? I'm fairly sure that datasets for me are always written to disk ...
I ran a similar test (identical code, except for correcting the missing
CARDS; statement, and 1/4 as many records to make it not too slow on my
desktop) and got much more variable results; this is on an early Core2Duo
dual core machine (1GB RAM, SATA2 HDD)
All runs are DATA A / DATA WORK.A and are actual times, not CPU times. CPU
time is nearly identical across all runs, 0.50 sec +/- 0.05 sec.
First run: 7.03 / 5.71
Second: 14.26/15.62
Third: 8.15/4.31
Fourth: 3.42/3.76
It's certainly possible that Outlook or something else might have started up
during one or the other, so this is far from conclusive, but I certainly
don't seem to see a difference here.
Does your log show both like
The data set WORK.A has 1500000 observations and 3 variables.
(but with a different number of obs.)? Or does the one show something other
than WORK.A ?
-Joe
On Thu, Jan 22, 2009 at 5:30 PM, Arthur Tabachneck <art297@netscape.net>wrote:
> Hopefully, those more knowledgeable than me will chime in once I post this.
>
> I have always thought that the two were equivalent but, from the test I
> just ran, they don't appear to be.
>
> The two programs I ran, fifteen times in succession, and their results are
> shown below. I was extremely surprised that 'data a' ALWAYS ran faster
> than 'data work.a'.
>
> Can anyone explain why I obtained those results? FWIW, the tests were run
> on a 4-processor windows-based server running 9.1.3 after everyone else
> had left the office.
>
> Art
>
> DATA A; DATA work.a;
> INPUT A B; INPUT A B;
> do i=1 to 2000000; do i=1 to 2000000;
> output; output;
> end; end;
> cards;
> 1 2 1 2
> 1 3 1 3
> 2 5 2 5
> ; ;
> results:
>
> real time 2.07 seconds 7.29 seconds
> cpu time 2.01 seconds 2.01 seconds
>
> real time 2.06 seconds 5.87 seconds
> cpu time 2.04 seconds 2.00 seconds
>
> real time 2.09 seconds 5.29 seconds
> cpu time 2.07 seconds 2.01 seconds
>
> real time 2.17 seconds 6.10 seconds
> cpu time 2.04 seconds 1.99 seconds
>
> real time 2.37 seconds 5.46 seconds
> cpu time 2.04 seconds 2.03 seconds
>
> real time 2.09 seconds 4.73 seconds
> cpu time 2.09 seconds 2.00 seconds
>
> real time 2.01 seconds 5.67 seconds
> cpu time 1.99 seconds 2.10 seconds
>
> real time 2.07 seconds 5.38 seconds
> cpu time 2.09 seconds 2.04 seconds
>
> real time 2.15 seconds 8.45 seconds
> cpu time 2.00 seconds 2.01 seconds
>
> real time 2.01 seconds 4.53 seconds
> cpu time 2.00 seconds 1.97 seconds
>
> real time 2.01 seconds 5.03 seconds
> cpu time 2.00 seconds 2.01 seconds
>
> real time 2.04 seconds 6.10 seconds
> cpu time 2.03 seconds 2.06 seconds
>
> real time 5.65 seconds 6.48 seconds
> cpu time 2.04 seconds 2.04 seconds
>
> real time 2.17 seconds 5.62 seconds
> cpu time 2.03 seconds 1.98 seconds
>
> real time 2.04 seconds 6.67 seconds
> cpu time 2.01 seconds 2.01 seconds
> --------
> On Thu, 22 Jan 2009 16:28:50 -0500, SAS_learner <proccontents@GMAIL.COM>
> wrote:
>
> >Hello _all_,
> >
> >Once upon a time Long ago one fellow SAS programer told me that there is
> >difference between way we create work datasets. Say for example
> >
> >data test ;
> > set sashelp.class;
> >Run;
> >
> >is different
> >
> >Data work.test;
> > set sashelp.class ;
> >run;
> >
> >In the Second Method dataset test is stored in the work folder (either on
> C:
> >or Network ) ?? When You delete where would those datasets go not to
> recycle
> >bin
> >
> >thanks
> >SL
>
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