performance of SearchCursor and da.SearchCursor

ZachLiu1

I set up a comparison between SearchCursor and da.SearchCursor, the code is like this:

import arcpy, time  shp = r"C:\Users\THINK\Desktop\python\Data\TOWNS.shp"  #da SearchCursor sTime = time.clock() rows = arcpy.da.SearchCursor(shp, ["TOWN", "TOTAL_SQMI"]) for row in rows:     town = row[0]     area = row[1]     print ("The area of %s is %s sq miles."%(town, area))    del row, rows  eTime = time.clock() tDiff = eTime - sTime print "da SearchCursor uses %s seconds."%(tDiff)    #SearchCursor sTime = time.clock() rows = arcpy.SearchCursor(shp) for row in rows:     town = row.getValue("TOWN")     area = row.getValue("TOTAL_SQMI")     print ("The area of %s is %s sq miles."%(town, area)) del row, rows  eTime = time.clock() tDiff = eTime - sTime print "SearchCursor uses %s seconds."%(tDiff)

I assume da.SearchCursor will be faster but it took more than 2 seconds while SearchCursor finished in just 0.5 second.
Is there something wrong with the test?

Luke_Pinner

A few suggestions:

• Take out the print statement from inside the loop, that is adding a big overhead. 
• There's overhead in searchcursor setup, take that out of the timing
• Pass a field list to arcpy.SearchCursor as you are doing with da.SearchCursor i.e. arcpy.SearchCursor(shp, "", "", "TOWN;TOTAL_SQMI")
• In case there's some caching going on behind the scenes, put the tests in separate scripts (one that times the arcpy cursor and one that times the da searchcursor)
• Use the timeit module instead, example below:

if __name__ == '__main__':     import timeit     shp = r"D:\TEMP\test.shp"     print(timeit.timeit('for row in rows:id = row[0]',                         number=10,#run loop 10x and return average                         setup='import arcpy; rows = arcpy.da.SearchCursor(r"%s", ["PNTID"])'%shp))     print(timeit.timeit('for row in rows:id = row.getValue("PNTID")',                         number=10, #run loop 10x and return average                         setup='import arcpy; rows = arcpy.SearchCursor(r"%s", "", "", "PNTID")'%shp))

EDIT:Some performance tests on 1000 points, getting value of a single field.

* Printing field value in for loop
* Not passing field list to arcpy.SearchCursor
* searchcursor setup is included in timing
1. da.SearchCursor:    4.1257697098717925
2. arcpy.SearchCursor: 6.2084034116828475

* Not printing field value in for loop
* Not passing field list to arcpy.SearchCursor
* searchcursor setup is included in timing
3. da.SearchCursor:    0.07970193086012323
4. arcpy.SearchCursor: 2.196710119083276

* Not printing field value in for loop
* Not passing field list to arcpy.SearchCursor
* searchcursor setup is not included in timing
5. da.SearchCursor: 0.00738222613381
6. arcpy.SearchCursor: 0.160204482864

* Not printing field value in for loop
* Passing field list to arcpy.SearchCursor
* searchcursor setup is not included in timing
7. da.SearchCursor: 0.0075200788871
8. arcpy.SearchCursor: 0.118301085773

The above was generated using the following code:

if __name__ == '__main__':     import timeit     shp = r"D:\TEMP\test.shp"     s=''' rows = arcpy.da.SearchCursor(r"%s", ["PNTID"]) for row in rows:     print row[0]'''%shp     a=timeit.timeit(s,number=10,setup='import arcpy')      s=''' rows = arcpy.SearchCursor(r"%s") for row in rows:     print row.getValue("PNTID")'''%shp     b=timeit.timeit(s,number=10,setup='import arcpy')      s=''' rows = arcpy.da.SearchCursor(r"%s", ["PNTID"]) for row in rows:     id=row[0]'''%shp     c=timeit.timeit(s,number=10,setup='import arcpy')      s=''' rows = arcpy.SearchCursor(r"%s") for row in rows:     id=row.getValue("PNTID")'''%shp     d=timeit.timeit(s,number=10, setup='import arcpy')      e=timeit.timeit('for row in rows:id = row[0]',                         number=10,#run loop 10x and return average                         setup='import arcpy; rows = arcpy.da.SearchCursor(r"%s", ["PNTID"])'%shp)     f=timeit.timeit('for row in rows:id = row.getValue("PNTID")',                         number=10, #run loop 10x and return average                         setup='import arcpy; rows = arcpy.SearchCursor(r"%s")'%shp)      g=timeit.timeit('for row in rows:id = row[0]',                         number=10,#run loop 10x and return average                         setup='import arcpy; rows = arcpy.da.SearchCursor(r"%s", ["PNTID"])'%shp)     h=timeit.timeit('for row in rows:id = row.getValue("PNTID")',                         number=10, #run loop 10x and return average                         setup='import arcpy; rows = arcpy.SearchCursor(r"%s", "", "", "PNTID")'%shp)  print '1. da.SearchCursor:',a print '2. arcpy.SearchCursor:',b print '3. da.SearchCursor:',c print '4. arcpy.SearchCursor:',d print '5. da.SearchCursor:',e print '6. arcpy.SearchCursor:',f print '7. da.SearchCursor:',g print '8. arcpy.SearchCursor:',h