[HN Gopher] Nulls: Revisiting null representation in modern colu...
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       Nulls: Revisiting null representation in modern columnar formats
        
       Author : tosh
       Score  : 19 points
       Date   : 2024-10-30 20:26 UTC (1 days ago)
        
 (HTM) web link (dl.acm.org)
 (TXT) w3m dump (dl.acm.org)
        
       | zX41ZdbW wrote:
       | How did it go through peer review without a comparison with
       | ClickHouse?
       | 
       | > Our analysis shows that the Compact layout performs better when
       | Null ratio is high and the Placeholder layout is better when the
       | Null ratio is low or the data is serial-correlated.
       | 
       | ClickHouse uses a placeholder value with a separate stream with
       | NULL-masks, and additionally, it has the Sparse column format,
       | which is named Compact in the paper (but currently, the Sparse
       | format applies to encode default values more efficiently rather
       | than NULL values).
        
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       (page generated 2024-10-31 23:00 UTC)