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  1. Ignite
  2. IGNITE-14557

Improve row layout.

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    Details

    • Type: Improvement
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: None
    • Component/s: None
    • Labels:
    • Ignite Flags:
      Docs Required, Release Notes Required

      Description

      Motivation.

      When one try to read a column value from a row, the very first check will be a null-check.
      As Null-Table resides right after an Offset-Table, the we need 2 jumps to for the null-check.

      Description.

      Assuming, Null-Table reserves a bit for each columns even if the columns is not Nullable,
      Null-table has constant size (within same version of schema) and we no need extra bytes to persist it's length into the tuple.

      • Null-checks will not require extra read for Offset-Table size and extra jump.
      • Offset-Table will not need extra read/jump to reach as Null-Table size is constant.

      Let's just swap these tables in layout and fix docs README.md and IEP.

       

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              • Assignee:
                amashenkov Andrey Mashenkov
                Reporter:
                amashenkov Andrey Mashenkov
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