diff options
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 32 |
1 files changed, 29 insertions, 3 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index d8bf8466f58..2d9d261bb31 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -12009,6 +12009,7 @@ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx, key_part_end=key_part+table->key_info[idx].key_parts; key_part_map const_key_parts=table->const_key_parts[idx]; int reverse=0; + my_bool on_primary_key= FALSE; DBUG_ENTER("test_if_order_by_key"); for (; order ; order=order->next, const_key_parts>>=1) @@ -12023,7 +12024,31 @@ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx, for (; const_key_parts & 1 ; const_key_parts>>= 1) key_part++; - if (key_part == key_part_end || key_part->field != field) + if (key_part == key_part_end) + { + /* + We are at the end of the key. Check if the engine has the primary + key as a suffix to the secondary keys. If it has continue to check + the primary key as a suffix. + */ + if (!on_primary_key && + (table->file->table_flags() & HA_PRIMARY_KEY_IN_READ_INDEX) && + table->s->db_type == DB_TYPE_INNODB && + table->s->primary_key != MAX_KEY) + { + on_primary_key= TRUE; + key_part= table->key_info[table->s->primary_key].key_part; + key_part_end=key_part+table->key_info[table->s->primary_key].key_parts; + const_key_parts=table->const_key_parts[table->s->primary_key]; + + for (; const_key_parts & 1 ; const_key_parts>>= 1) + key_part++; + } + else + DBUG_RETURN(0); + } + + if (key_part->field != field) DBUG_RETURN(0); /* set flag to 1 if we can use read-next on key, else to -1 */ @@ -12034,7 +12059,8 @@ static int test_if_order_by_key(ORDER *order, TABLE *table, uint idx, reverse=flag; // Remember if reverse key_part++; } - *used_key_parts= (uint) (key_part - table->key_info[idx].key_part); + *used_key_parts= on_primary_key ? table->key_info[idx].key_parts : + (uint) (key_part - table->key_info[idx].key_part); if (reverse == -1 && !(table->file->index_flags(idx, *used_key_parts-1, 1) & HA_READ_PREV)) reverse= 0; // Index can't be used @@ -12738,7 +12764,7 @@ remove_duplicates(JOIN *join, TABLE *entry,List<Item> &fields, Item *having) field_count++; } - if (!field_count && !(join->select_options & OPTION_FOUND_ROWS)) + if (!field_count && !(join->select_options & OPTION_FOUND_ROWS) && !having) { // only const items with no OPTION_FOUND_ROWS join->unit->select_limit_cnt= 1; // Only send first row DBUG_RETURN(0); |