BEx Query Slower in Hana?

[vitran23]

We are in the process of upgrading our BW system to Hana and after some testing on our test hana system we've noticed that one of our queries is taking double the time to run than it does currently on our production system which runs with accelerator.  Has anyone had any issues during their hana upgrading stages ran into queries that took longer to run than it did in a BWA system?

[Former Member]

Hana has inside differents engines that make the calculations on each step of the procces to obtain and show information.

SAP says that you can migrate your current BW content to hana, but in order to get performance improvements, is needed to tune the query bex. Because is possible to have a problems like this.

you need to see where is the bottleneck and attack it.

consider this:

1) Delegate all the calculations to the database level.

2) apply filters in the database level

3) only transfer results (see if you are having issues in your network)

4) what Hana database version are you using with? Investigate if you are using a new HDB system.

5) Hana has several traces inside that you can enable and investigate. look for some information and try to use it.

hope it helps.

[vitran23]

I'm new to BW so do you have a clear step by step of how to complete the steps you just described?

Right now all we are looking for is the same performance that we had before the on BIA.  We have too many queries to currently to tune each one.  I believe when we decided to upgrade our queries would run at the same speed as our current BW system with BIA.

[Former Member]

maybe this document can give you a clue:

http://www.saphana.com/servlet/JiveServlet/previewBody/1888-102-1-2964/Query%20Performance%20in%20BW...

also, please provide  us with your hana server characteristics and HDB version in order to review if there are know issues.

[vitran23]

We are having SAP look into the issue.  We had to reboot our test system and it seem to speed things back up but that isn't a good solution.  Seems to be a memory leak somewhere.

[lbreddemann]

Hi Vi

Typically it can be expected that queries run at least as fast as off from a BWA.

In your case I recommend to check where the time is actually spent (use transaction RSRT for that).

Also worthwhile checking is if the setup of application servers for the old and the new BW instance are similar.

- Lars

[vitran23]

Yeah that's how we started to determine that the query was running slow.  There are a couple of cubes that it's looking that that are more than 4x longer than it was in the non hana system so I'm wondering if there is some configuration in the cube that would need to be done instead of just hana optimizing it.

[lbreddemann]

Ok, so you used RSRT already. Awesome.

Show us the query stats then from the original and from the SAP HANA system.

Should not be too difficult so get an idea of whats going on.

- Lars

[vitran23]

Attached are pictures of the RSRT outputs with sum's.

Production

Test System

[lbreddemann]

Could it be that you uploaded the same picture twice?

[vitran23]

Here's the correct picture.

[lbreddemann]

That's actually rather weird. Less data gets processed but more time is required for that.

Since this is true even for the rather small result sets I propose you check your system setup - especially the network connect to the SAP HANA server.

Also, you might want to open a support incident.

- Lars

[vitran23]

I don't disagree which makes it more odd.  It's not doing it for all queries but this is one of our most used one that we need to resolve the run time issue.

[vitran23]

What could I pass onto the Basis team to look at as far as server configurations or connection?