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  1. Ignite
  2. IGNITE-14846

Default statistics

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    Description

      To simplify optimizer and to get a little bit more accurate estimation Ignite can generate some default statistics for each table (each column and so on) based on tables metadata. For example:

      boolean non null field can produce a following statistics:

      min: false

      max: true

      nulls: 0

      distinct: 2

      total: <table_size>

      while

      uuid nullable column can produce:

      min: 00-00-00-00...

      max: FF-FF-FF-...

      nulls: <table_size> * 0.1

      distinct: <table_size> * 0.5

      total: <table size>

      It can be generated on the fly by statistics subsystem (and cached for future usages).

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          is blocked by

          Improvement - An improvement or enhancement to an existing feature or task. IGNITE-14307 Calcite. Use statistics in cost model.

          • Critical - Crashes, loss of data, severe memory leak.
          • Resolved
          is part of

          New Feature - A new feature of the product, which has yet to be developed. IGNITE-12248 Apache Calcite based query execution engine

          • Major - Major loss of function.
          • Open

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              Unassigned Unassigned
              Berkov Alexander Belyak
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                Created:
                Updated: