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Is there any better way to improve performance of the TOPK-Projections?

We have some tables which are created in temporal model. For that I believe TOPK projections could be helpful. However refreshing and creating a fresh new topk projection takes lot of time especially table with 800K + records. Is there any best practices for creating and managing TOPK projections to improve the performance. Additionally, sometimes when using TOPK projections, the query hits the MaxOptMemMB although we set the size this to 400MB.

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Answers

  • Is the table partitioned? That might improve the performance, and allow it some "breathing room" for the calculation. The order by clause of the projection is also gonna have a pretty significant impact, as well as the "depth" of the top-k. So, if you're drilling down a bunch of columns into the top-k, it's gonna have to do a lot of work as well. Can you provide some more specifics about what you're creating and what it looks like?

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