How to trigger alert Column store unload for reason :unused resource

[Former Member]

Good day,

I have an issue with the column store unload.

As for this alert in hana studio, there are 3 reasons for the alert. Reason: Low memory, Explicit, Unused resource.

First one is lack of memory, so the column table is unloaded. Second is because someone unloads a column table by SQL. These two reason we can see easily and they are usually main reasons for this alert. However, i can't trigger the last one.

Is there any good method to trigger it?

I attached some screens files of the workaround.

Any help will be appreciated.

Thank you!

Best regards

Geoffrey Zhang

Message was edited by: Tom Flanagan

[lbreddemann · Accepted solution]

Why do you want to trigger the unload with a specific reason?

The unload reason you ask about is used when the system determines to get rid of a resource container that has not been used for a long time - it is an automatic feature, that doesn't have a 'user interface'.

Hmm... I wonder why so many SAP colleagues seem to have difficulties with using our internal forums to clarify their questions...

- Lars

[Former Member · Accepted solution]

Thank you very much first.

Because recently I dealing with some alert. And now I need to write the KBA about HANA Alert 55 Column store unloads. So I need to figure out every situation and give the complete method to handle this alert.

As for why people don' t like to use the forums, to be honest, I'm not sure. Maybe language problem, maybe they think it's not easier than email or refer to someone directly, even not real time. I'm really not sure, but I' m really interested in using the forums, like this, I have been troubled by this problem for one day. However, I wrote my problem down, and you saw that, just a few words, had already helped me a lot. It's so great. Of course, not every question or talk can be solve or discuss. For example, I have 3 question in SCN this week, until now there is still one about SSFS needed to be solved. Not real time. Maybe this is a main reason.

No matter what, thanks for your help. I'm in China, if you are interested in China or have other topics want to share, I will be glad to communicate with you.

Nice talk with you.

Geo

[lbreddemann · Accepted solution]

Hi Geo

not too sure if the idea for KBAs has changed but in my understanding they were never meant to replace documentation or to provide complete topic overviews.

Given the nature of this alert, it would be weird to

a) get an alert at all for this

b) have someone reacting to it.

The function to unload containers after they haven't been used in a long time is part of the garbage collection in SAP HANA. Why would it be necessary to have an alert for that?

And then what should anyone do about it? What do DBAs usually do, when long unused data gets displaced to disk?

Exactly: nothing

Concerning my remark about SCN usage of SAP employees: I meant that there are plenty of SAP internal forums and communities available where you can probably get less exposure to the rest of the world and might get answers that provide you with more detailed information than what is possible in SCN.

As English is the corporate language and used in SCN as in the internal forums I don't see how that is an obstacle for using the internal forums.

About your unanswered questions: just like any other forum, SCN is based on voluntary contributions. There should be no expectation about how long it takes to get answers.

Nobody is paid to answer the questions here, so it's all on a community basis.

- Lars

[Former Member · Accepted solution]

Hi Lars,

Of course you are right. Plenty of SAP internal forums and communities are available, and which can help us get less exposure to the rest of the world indeed. And it's also right that nobody is paid to answer the questions here.

However, someone maybe just not used to using internal forums, and so many years before they join in SAP, they are always using other ways to search answers, as Google, Baidu and so on. As we all knows, habit is a terrible and also a respectable strength. So we need to advocate our internal forums and communities as it has so many advantages like you said. More people in, more answers back. And that will be a virtuous circle.

Indeed, nobody is paid to answer the questions here. Because our colleagues are usually busy, sometimes they may not have so much time to SCN or other forums. Some questions can't get the answer in time. So maybe it's also a kind of reason. Hence, I think I'm very lucky that you helped me so quickly. Thanks a lot.

As for the alert, I think we should find every reason of triggering it, even though we may not need to do something for every situation, however, we should know its theory. KBAs are not only for customers, but also for our colleagues. So more in details, more easily we study.

Geo

[lbreddemann · Accepted solution]

Stumbled over this SAP NOTE

2058284

Table loads traced into the unload file

today.

Might be interesting for you and your KBA.

- Lars

[Former Member · Accepted solution]

Thank you Lars! Really usefull information!

Regards!

- Edgar González

[Former Member · Accepted solution]

Thank you very much.

It really helps a lot.

Geo