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  1. MariaDB ColumnStore
  2. MCOL-4834

Help text and definition for columnstore_compression_type are inconsistent about support for NO_COMPRESSION

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Details

    • Bug
    • Status: Closed (View Workflow)
    • Major
    • Resolution: Fixed
    • 6.1.1
    • 6.3.1
    • None
    • None
    • 2021-15, 2021-17

    Description

      In ColumnStore 6.1.1, the NO_COMPRESSION option for columnstore_compression_type was replaced with a third occurrence of SNAPPY:

      const char* mcs_compression_type_names[] = {
          "SNAPPY", // 0
          "SNAPPY", // 1
          "SNAPPY", // 2
      #ifdef HAVE_LZ4
          "LZ4",    // 3
      #endif
          NullS
      };
      

      https://github.com/mariadb-corporation/mariadb-columnstore-engine/blob/columnstore-6.1.1-1/dbcon/mysql/ha_mcs_sysvars.cpp#L24

      However, the help text for the system variable still refers to the NO_COMPRESSION option:

      // compression type
      static MYSQL_THDVAR_ENUM(
          compression_type,
          PLUGIN_VAR_RQCMDARG,
          "Controls compression algorithm for create tables. Possible values are: "
          "NO_COMPRESSION segment files aren't compressed; "
          "SNAPPY segment files are Snappy compressed (default);"
          "LZ4 segment files are LZ4 compressed;",
          NULL, // check
          NULL, // update
          1, //default
          &mcs_compression_type_names_lib); // values lib
      

      https://github.com/mariadb-corporation/mariadb-columnstore-engine/blob/columnstore-6.1.1-1/dbcon/mysql/ha_mcs_sysvars.cpp#L41

      So these two items are inconsistent:

      • If columnstore_compression_type should no longer support NO_COMPRESSION, then it should most likely be removed from the help text.
      • If columnstore_compression_type should still support NO_COMPRESSION, then it should most likely be added back to mcs_compression_type_names.

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            dleeyh Daniel Lee (Inactive)
            GeoffMontee Geoff Montee (Inactive)
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            Dates

              Created:
              Updated:
              Resolved:

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