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Does use of DocValues provide any performance improvement for Grouping ? I' looked into the blog which mentions improving Grouping performance through DocValues.

https://lucidworks.com/blog/fun-with-docvalues-in-solr-4-2/

Right now, Group by queries (which I can't sadly avoid) has become a huge bottleneck. It has an overhead of 60-70% compared to the same query san group by. Unfortunately, I'm not able to be CollapsingQParserPlugin as it doesn't have a support similar to "group.facet" feature.

My understanding on DocValues is that it's intended for faceting and sorting. Just wondering if anyone have tried DocValues for Grouping and saw any improvements?

mlissner
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Shamik
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  • yes, i write some code that act similar to grouping (block join stuff) and I used docvalues, it helps. – Mysterion Jan 21 '15 at 21:34
  • @Mysterion .. thanks, I'm giving it a shot, hopefully will see some improvement. – Shamik Jan 22 '15 at 23:59
  • @Shamik did you see any improvement? – BestPractices Aug 20 '15 at 01:03
  • @BestPractices .. Unfortunately no, docvalues didn't make any difference in grouping performance. I'm looking forward to this --> https://issues.apache.org/jira/browse/SOLR-4763 . I don't see any traction on CollapsingQParserPlugin group.facet support yet. – Shamik Aug 21 '15 at 06:07
  • @Shamik did you have any luck improving group.facet performance? – Ovidiu Sep 15 '15 at 14:55
  • My understanding of the CollapseQParserPlugin is that it facets based on the grouped results. Is that your intent? From the ticket that created the feature, it says, "The result count and facet counts automatically line up with the collapsed doclist/docset." – mlissner Oct 19 '16 at 23:36
  • https://issues.apache.org/jira/browse/LUCENE-9328 Sorting by DocValues while grouping is slower than old good FieldCache – mkhludnev Dec 04 '21 at 21:21

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