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Here you'll find the recordings of our Techspert Talks sessions (formally Support Techspert Thursdays).

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QlikView Memory Management[1]

In this webinar we will discuss:

  • How QlikView uses memory
  • How to identify your memory hogs
  • Best practices for efficient memory usage

For best viewing, we recommend you set the highest video resolution.

Q&A - QlikView Memory Management

Q: For better memory utilization, do you recommend people to make application as small as possible and utilize dcoument chaining? Do you have other recommendation to have better memory usage?

A: Document chaining is a good way to link bigger documents. The downside when it comes to Memory usage is that the next document will need to be loaded into memory, and that takes time in increases memory footprint.

Q: Does User Input fields on document also increasy memory usage ?

A: Yes, the use of input fields affects memory usage, and also the size of the .Shared file.

Q: How to track each document consumed 3 types of memory that you showed on the graph?

A: The only good way of determining the memory usage fopr a specific document is to load them one at a time on the server and observer the memory usage, both with just the document loaded and when users start to interact with it.

Q: What happens with an old cached data (assuming the app timed out) when a new version of the app is loaded into QVS?

A: The results sets in teh cache wil be kept in the cache until the working set limits are reached, or the QVS restarts.

Q: Where can I find the Audit log?

A: By default, the Audit log can be found in C:\ProgramData\QlikTech\QlikViewServer. Thios location can be changed in the QMC under the settings for the QVS.

Q: When/how is the information in shared file "associated" to a loaded document? In SR12, bookmarks are not visible in a preloaded document until the user close and reopen his session. What can cause this? How do we solve it?

A: The infomration in the Shared file is loaded into memory when the document is. We have seen a bug on this in connection to Preload in recent releases, aso this should be fixed in the lastest ServiceRelease.

Q: Is the "Clear QVS cache" option to all versions of QVS or starting at a specific version?

A: This settng has been in the QVS since at least QlikView 10

Q: Aside from QVS restart/cache, is there any value in restarting all services on a regular basis? If so, why would we want to do that?

A: No, restarting the services will just remove the cache from memory, and will make the end user experience worse.

Q: If I set ClearCacheTimesPerDay, will it wait for jobs to finish before clearing QVS cache?

A: No, but tasks will not be affected by the QVS cache clearing.

Q: Is the cache cleared after a reload?

A: No.

Q: is there a document outlining type of data models and their expected memory impact on RAM?

A: ll documentation ond research we have in this are is on our community under Scalability Center. https://community.qlik.com/groups/qlikview-scalability

Q: Assume that all cache and user session data related to document is completely cleared when new version of document is availlable?

A: No, the cache remains and the session remains, it is only the data in the document that changes.

Q: I know that the minimum memory requirement for a 64-bit machine is 8GB. From your experience, what is an acceptable amount of memory to allocate to the QV server based on each additional QV document being stored in memory? (assuming each doc is complex)

A: There really is no way of answer that question except for testing each document for its own memory footprint.

Q: We are not preloading any document but we have qlik publisher and server on same box and preloading document is off.

does it mean all document will be kept in RAM after refreshed via publisher?

A: If the documents are not preloaded, they will be governed by the Document timeout as shown in this session. The clock for the timeout will start ticking when the last user session has left the document. Reload tasks will have no effect on this behavior.

Q: Why are cache results not removed from memory as QVW is reloaded+republished? Our app is reloaded every 2 hours, but still mem used by QVS.EXE increases on user interaction until limits are reached.

A: The cached result sets will be kept in cache until the working set limits are reached, as they might be reused to improve the end user experience.

Q: Can time out set differently for each document?

A: The document tiemout is a global setting. Setting it low and then setting "Preloaded" on the documents you want to always be in memory is a workaround that gives some flexibility.

Q: What happens to the windows virtual memory ? do we have to configure it to the minimum to force Windows to use physical RAM?

A: We normally advice to let Windows manage Page file size, as it will prioritize using RAM.

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