abstractdog commented on PR #6758:
URL: https://github.com/apache/hive/pull/6758#issuecomment-5567313232

   benchmark results: different filter selectivity, done for plain and 
dictionary types:
   ```
   ┌────────┬────────────────┬────────────────┬───────────────┬────────────────┐
   │ filter │   dict × on    │   dict × off   │  plain × on   │  plain × off   │
   ├────────┼────────────────┼────────────────┼───────────────┼────────────────┤
   │ none   │ baseline 10681 │ baseline 10627 │ baseline 9875 │ baseline 10013 │
   ├────────┼────────────────┼────────────────┼───────────────┼────────────────┤
   │ 10     │ −24.4%         │ −20.8%         │ −5.6%         │ −4.2%          │
   ├────────┼────────────────┼────────────────┼───────────────┼────────────────┤
   │ 50     │ −17.8%         │ −18.2%         │ −4.7%         │ −3.7%          │
   ├────────┼────────────────┼────────────────┼───────────────┼────────────────┤
   │ 90     │ +1.2%          │ −7.8%          │ −0.7%         │ −8.5%          │
   └────────┴────────────────┴────────────────┴───────────────┴────────────────┘
   ```
   Dict path: the bulk-skip fast path pays. At 10% pass (skip 90% of rows), 
reject runs coalesce into single RunLengthBitPackingHybridDecoder.skipInts 
calls and the bench saves ~24% wall-clock. At 50% pass it's still ~18%. At 90% 
pass, the gap collapses because most rows still materialize.


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