[#MDEV-19345] Cleanup inconsistency in setting HA_(BLOB|VAR_LENGTH|BIT)

There are three similar code pieces setting KEY_PART_INFO::key_part_flag, but there is a difference in every piece.

We should check all three pieces for bugs and get rid of duplicate code, for example by introducing new virtual methods in Field, with approximately this prototype:

uint key_part_flags() const;

uint key_part_store_length(const KEY_PART_INFO &part) const;

sql_select.cc: create_tmp_table()

      key_part_info->store_length= key_part_info->length;

      if ((*reg_field)->type() == MYSQL_TYPE_BLOB ||

          (*reg_field)->real_type() == MYSQL_TYPE_VARCHAR ||

          (*reg_field)->type() == MYSQL_TYPE_GEOMETRY)

        if ((*reg_field)->type() == MYSQL_TYPE_BLOB ||

            (*reg_field)->type() == MYSQL_TYPE_GEOMETRY)

          key_part_info->key_part_flag|= HA_BLOB_PART;

        else

          key_part_info->key_part_flag|= HA_VAR_LENGTH_PART;

        key_part_info->store_length+=HA_KEY_BLOB_LENGTH;

      keyinfo->key_length+= key_part_info->store_length;

Does not set HA_BIT_FLAG for the BIT data type
Sets HA_BLOB_PART for the GEOMETRY data type

table.cc: TABLE_SHARE::init_from_binary_frm_image()

        if (field->type() == MYSQL_TYPE_BLOB ||

            field->real_type() == MYSQL_TYPE_VARCHAR ||

            field->type() == MYSQL_TYPE_GEOMETRY)

          if (field->type() == MYSQL_TYPE_BLOB ||

              field->type() == MYSQL_TYPE_GEOMETRY)

            key_part->key_part_flag|= HA_BLOB_PART;

          else

            key_part->key_part_flag|= HA_VAR_LENGTH_PART;

          key_part->store_length+=HA_KEY_BLOB_LENGTH;

          keyinfo->key_length+= HA_KEY_BLOB_LENGTH;

        if (field->type() == MYSQL_TYPE_BIT)

          key_part->key_part_flag|= HA_BIT_PART;

Sets HA_BIT_FLAG for the BIT data type
Sets HA_BLOB_PART for the GEOMETRY data type

table.cc: TABLE::create_key_part_by_field()

  if (field->type() == MYSQL_TYPE_BLOB ||

      field->type() == MYSQL_TYPE_GEOMETRY ||

      field->real_type() == MYSQL_TYPE_VARCHAR)

    key_part_info->store_length+= HA_KEY_BLOB_LENGTH;

    key_part_info->key_part_flag|=

      field->type() == MYSQL_TYPE_BLOB ? HA_BLOB_PART: HA_VAR_LENGTH_PART;

Does not set HA_BIT_FLAG for the BIT data type
Sets HA_VAR_LENGTH_PART for the GEOMETRY data type (the previous two pieces set HA_BLOB_PART for GEOMETRY)

[MDEV-19345] Cleanup inconsistency in setting HA_(BLOB\|VAR_LENGTH\|BIT)_PART flags Created: 2019-04-26 Updated: 2019-09-23 Resolved: 2019-06-04
Status:	Closed
Project:	MariaDB Server
Component/s:	Data types, Optimizer
Fix Version/s:	10.5.0

[MDEV-19345] Cleanup inconsistency in setting HA_(BLOB|VAR_LENGTH|BIT)_PART flags Created: 2019-04-26 Updated: 2019-09-23 Resolved: 2019-06-04

sql_select.cc: create_tmp_table()

table.cc: TABLE_SHARE::init_from_binary_frm_image()

table.cc: TABLE::create_key_part_by_field()