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IF THEN ELSE Optimization

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Occasional Contributor
Posts: 8
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IF THEN ELSE Optimization

[ Edited ]

Hello,

 

Part of a program I am working on takes an excessive amount of time to complete; CPU time is slightly over seven minutes, however, real time has been over two hours when run against the full data set of approximately two million records. The program will be scheduled to run daily when complete so any efficiency we can gain will be worth it in the long run. I am working in SAS EG 7.13 via Citrix and there are some known performance problems with our SAS GRID 9.4 at the moment, however, I am hoping there may be a way to better optimize the code below to reduce at least some processing time:

 

/* measure elapsed time and determine sla performance */

data work.out;

set work.in;

format SLA_Performance $Char6. Reporting_Date Extract_Date date9.;


  /* determine reporting_date */

  if disposition in ('Completed','Canceled') then
    do;
      reporting_date = datepart(Last_Modified_DT);
    end;
  else
    do;
      reporting_date = today();
    end;


  /* measure elapsed time */

  real_time = intck('days', DatePart(Submitted_Date), reporting_date);
  bank_time = intck('bankingdays', DatePart(Submitted_Date), reporting_date);


  /* determine SLA Performance */
  
  if SLA_Date = . then
    do;
      SLA_Performance = 'NA';
    end;

  else if SLA_Date >= reporting_date then
    do;
      SLA_Performance = 'Within';
    end;

  else
    do;
      SLA_Performance = 'Over';
    end;


  /* record extract date */

  Extract_Date = today();

run;

 


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Solution
4 weeks ago
Super User
Posts: 13,583

Re: IF THEN ELSE Optimization

Posted in reply to VictorSirianni

One thing to look at:

if SLA_Date = . then
    do;
      SLA_Performance = 'NA';
    end;

  else if SLA_Date >= reporting_date then
    do;
      SLA_Performance = 'Within';
    end;

  else
    do;
      SLA_Performance = 'Over';
    end;


Which of those first two cases occurs most frequently? If you can set it as the first condition then the whole block might runt faster.

 

Example if SLA_date is missing on only 1percent of the records and SLA_date > reporting_date on 80% of the records reversing the order of comparison would reduce the number times the SLA_date is compared to . a whole bunch.

 

If you move the line Extract_Date = today(); to before the first If then you could use

reporting_date = Extract_date; instead of the overhead of calling TODAY(twice).

Similar with calling DatePart(Submitted_Date) twice. I might run faster to create a temporary variable by calling datepart once and using that value in the INTNX calls.

Another consideration may be questioning the datetime values at all. If you don't use them for some other process where the time component is critical perhaps consider replacing them with date values so you need not call the datepart function at all.

 

The Today and Datepart functions may not take up much time but cumulatively over two million + records it might be noticed.

 

Since the code on that data step isn't very complex I suspect either disk usage or network bottlenecks are more likely to be eating you time.

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Regular Contributor
Posts: 164

Re: IF THEN ELSE Optimization

Posted in reply to VictorSirianni

i doubt it will affect processing time but you don't need the 'do' and 'end' statements. Is there some reason for it, eg readability or something?

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Solution
4 weeks ago
Super User
Posts: 13,583

Re: IF THEN ELSE Optimization

Posted in reply to VictorSirianni

One thing to look at:

if SLA_Date = . then
    do;
      SLA_Performance = 'NA';
    end;

  else if SLA_Date >= reporting_date then
    do;
      SLA_Performance = 'Within';
    end;

  else
    do;
      SLA_Performance = 'Over';
    end;


Which of those first two cases occurs most frequently? If you can set it as the first condition then the whole block might runt faster.

 

Example if SLA_date is missing on only 1percent of the records and SLA_date > reporting_date on 80% of the records reversing the order of comparison would reduce the number times the SLA_date is compared to . a whole bunch.

 

If you move the line Extract_Date = today(); to before the first If then you could use

reporting_date = Extract_date; instead of the overhead of calling TODAY(twice).

Similar with calling DatePart(Submitted_Date) twice. I might run faster to create a temporary variable by calling datepart once and using that value in the INTNX calls.

Another consideration may be questioning the datetime values at all. If you don't use them for some other process where the time component is critical perhaps consider replacing them with date values so you need not call the datepart function at all.

 

The Today and Datepart functions may not take up much time but cumulatively over two million + records it might be noticed.

 

Since the code on that data step isn't very complex I suspect either disk usage or network bottlenecks are more likely to be eating you time.

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