topic Re: How do reset the table buffer in Application Development and Automation Discussions

How do reset the table buffer

former_member610230 — Wed, 10 Feb 2021 14:17:48 GMT

The situation is as follows. After executing the SELECT request, I calculate the processing time. After the second time and further, the processing time is significantly less. Because the data is saved to the buffer. Q: How do I reset the table buffer? It is necessary that the requests after the first time are equal to the first time.

I tried tcode /$SYNC and /$TAB. No changes. It feels like we need to clear something else, or another transaction is needed. There must be something, anyway. Otherwise, if you run the query once a day, it will be equally long. Where is the dog buried???

Don't say it's impossible.

Re: How do reset the table buffer

FredericGirod — Wed, 10 Feb 2021 14:22:54 GMT

why didn't you manage the processing time after the first call ?

in real life you will have only one time the first call and several times the others

Re: How do reset the table buffer

Patrick_vN — Wed, 10 Feb 2021 15:11:21 GMT

Have you considered bypassing the buffer in your SQL statement instead?

  SELECT matnr mtart FROM mara INTO TABLE it_mara BYPASSING BUFFER.

Re: How do reset the table buffer

former_member610230 — Wed, 10 Feb 2021 15:21:31 GMT

The reason is clear. You need to clear the buffer at the database level. I tried to do it using native SQL. In the end, it was refused due to a lack of authority.

Re: How do reset the table buffer

joltdx — Wed, 10 Feb 2021 15:22:15 GMT

Yes, this is the best way for you. But I really wonder WHY you would want this. Why do you want things to go slower? And resetting the buffer resets it for the entire system. The /$SYNC and /$TAB affect many things, so they shouldn't really be used unless really necessary... o_O

Also, this is bypassing the SAP buffer. Depending on the database system, there are most likely other buffers as well on the way from your code to the data. But I really doubt that clearing all of those is a good thing to do. And there's no access to that from within SAP anyway... 🙂

Re: How do reset the table buffer

abo — Wed, 10 Feb 2021 15:25:54 GMT

I find it amusing that the link in the English documentation uses the German spelling "puffer" 😉

Re: How do reset the table buffer

joltdx — Wed, 10 Feb 2021 15:28:17 GMT

I hope you have a good reason, but it's not clear to me... I would strongly advice against clearing any buffers. Especially down in the database. It affects the entire database and SAP system negatively, not only your query!

Re: How do reset the table buffer

joltdx — Wed, 10 Feb 2021 15:31:55 GMT

Please do not clear the buffers.

If the equal processing time is really really important (for some reason I don't get), why don't you run your queries twice each time. The first time to equalize the buffers between runs, and the second time for measurements?