Performance wise which one is better: loop inside select single or select outside loop and reading inside loop

[Former Member]

Hi All,

I am having code like shown below...

loop at it_vbeln.

   SELECT * FROM vbfa  WHERE vbeln = it_vbeln-vbeln.

   SELECT SINGLE * FROM vbkd WHERE vbeln = vbfa-vbelv.

endloop.

whether can i use the select statements outside the loop?

select VBELN

          POSNR

          KDGRP

          PLTYP

from vbfa

into table it_vbfa

for all entries in it_vbeln

where vbeln = it_vbeln-vbeln.

after that...

loop at it_vbeln.

read table it_vbfa into wa_vbaf with key vbeln = it_vbeln-vbeln.

endloop.

Which one is better....inside loop select single is better or use select outside the loop and read the table...

But when i seen the execution time select single inside loop is taking less time as compared with select outside loop and reading inside loop.

Please advise.

Regards

Ram

[yuri_ziryukin]

Hello Ram,

1) as far as I remember selecting from VBFA with VBELN is bad (no index). There is a good SAP note for this, please study carefully: 185530.

2) Select outside a loop should be better. The other results might be caused by the differences between subsequent executions. Please select outside of loop!

Yuri

[HermannGahm]

additionally make sure it_vbfa is a sorted table (binary search).

in my system there is a delivered non activated index on

MANDT

VBELN

POSNN

vor vbfa (index M01).

check if you need to activate it...

[matt]

http://scn.sap.com/thread/3254323

locked.