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  1. MariaDB Server
  2. MDEV-20760

Add Type_handler::KEY_pack_flags()

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      Description

      This code in mysql_prepare_create_table() is not friendly to data type plugins:

             /* Use packed keys for long strings on the first column */
             if (!((*db_options) & HA_OPTION_NO_PACK_KEYS) &&
                 !((create_info->table_options & HA_OPTION_NO_PACK_KEYS)) &&
                 (key_part_length >= KEY_DEFAULT_PACK_LENGTH &&
                  (sql_field->real_field_type() == MYSQL_TYPE_STRING ||
                   sql_field->real_field_type() == MYSQL_TYPE_VARCHAR ||
                   f_is_blob(sql_field->pack_flag))) && !is_hash_field_needed)
             {
               if ((column_nr == 0 && f_is_blob(sql_field->pack_flag)) ||
                   sql_field->real_field_type() == MYSQL_TYPE_VARCHAR)
                 key_info->flags|= HA_BINARY_PACK_KEY | HA_VAR_LENGTH_KEY;
               else
                 key_info->flags|= HA_PACK_KEY;
             }
      

      Let's add a new method in Type_handler:

      virtual ulong KEY_pack_flags(uint column_nr) const { return 0; }
      

      So the above code will change to:

             /* Use packed keys for long strings on the first column */
             if (!((*db_options) & HA_OPTION_NO_PACK_KEYS) &&
                 !((create_info->table_options & HA_OPTION_NO_PACK_KEYS)) &&
                 (key_part_length >= KEY_DEFAULT_PACK_LENGTH) &&
                 !is_hash_field_needed)
             {
               key_info->flags|= sql_field->type_handler()->KEY_pack_flags(column_nr);
             }
      

      Data type plugins will be able to override this method.

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              Assignee:
              bar Alexander Barkov
              Reporter:
              bar Alexander Barkov
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                Created:
                Updated:
                Resolved: