Performance COEP / COVP index

[Missschaaa]

Hello guys,

I know there are lots of threads about COEP performance problems and many opinions. But maybe someone can give me a clear statement about the best way to read data from COEP / COVP with non-key fields.

My problem is, that I select the data by field OBJNR from COEP/COVP. The first question is which table is better for performance? Normally I would say COEP because it catches only data from one table. But maybe COVP is optimized for reading?

The second thing is about the way to select the data. In normal case I only have OBJNR as value for the select. In better cases I also can use KSTAR, GJAHR and PERIO. Now I see in COEP there is a database index

MANDT / KSTAR / GJAHR / PERIO / OBJNR

which looks pretty good for my problem. What happens now if I have selection criteria for other non key fields e.g. the WRTYP field. Is it more performant if also use them in the select satement or would it be even more unperformant?

Regards
Michael

[FredericGirod]

Hi Michael,

the answer is never simple with SAP & performance, for me it depends of your system & your administrator.

Why? Because it depends of the index quality of your database. The first thing is to analyse the selection made in your development. You could do it using ST05 and explain. SAP will estimate the time for several way to find your data, these estimation are made using the index statistic.

If the index quality is poor & the statistic never refresh ... the result will be a disaster, even if your code is perfect.

regards

Fred

[Missschaaa]

Hey Fred,

thanks a lot for your answer. I do not have that much knowledge about response times etc. from databases, I'm just writing the abap code 🙂 So the ST05 are some kind of cryptic for me. On which factors can I see that the statistic never refreshs and the index quality is poor?

My second problem is how to use the ST05. I found some wikis about it but it looks like that SAP updated the transaction for a couple of time. I first wanted to have a look which index has been used but could not find it. There is no button 'Explain' anymore in ST05 and the execution plan looks a little bit reduced than I can see it from screenshots in SAP wiki.

Regards

Michael