diff options
Diffstat (limited to 'sql/table.cc')
| -rw-r--r-- | sql/table.cc | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/sql/table.cc b/sql/table.cc index c951351fba8..2347e74e13c 100644 --- a/sql/table.cc +++ b/sql/table.cc @@ -6117,6 +6117,52 @@ void TABLE::create_key_part_by_field(KEY *keyinfo, /** @brief + Check validity of a possible key for the derived table + + @param key the number of the key + @param key_parts number of components of the key + @param next_field_no the call-back function that returns the number of + the field used as the next component of the key + @param arg the argument for the above function + + @details + The function checks whether a possible key satisfies the constraints + imposed on the keys of any temporary table. + + @return TRUE if the key is valid + @return FALSE otherwise +*/ + +bool TABLE::check_tmp_key(uint key, uint key_parts, + uint (*next_field_no) (uchar *), uchar *arg) +{ + Field **reg_field; + uint i; + uint key_len= 0; + + for (i= 0; i < key_parts; i++) + { + uint fld_idx= next_field_no(arg); + reg_field= field + fld_idx; + uint fld_store_len= (uint16) (*reg_field)->key_length(); + if ((*reg_field)->real_maybe_null()) + fld_store_len+= HA_KEY_NULL_LENGTH; + if ((*reg_field)->type() == MYSQL_TYPE_BLOB || + (*reg_field)->real_type() == MYSQL_TYPE_VARCHAR || + (*reg_field)->type() == MYSQL_TYPE_GEOMETRY) + fld_store_len+= HA_KEY_BLOB_LENGTH; + key_len+= fld_store_len; + } + /* + We use MI_MAX_KEY_LENGTH (myisam's default) below because it is + smaller than MAX_KEY_LENGTH (heap's default) and it's unknown whether + myisam or heap will be used for the temporary table. + */ + return key_len <= MI_MAX_KEY_LENGTH; +} + +/** + @brief Add one key to a temporary table @param key the number of the key @@ -6146,6 +6192,7 @@ bool TABLE::add_tmp_key(uint key, uint key_parts, KEY* keyinfo; Field **reg_field; uint i; + bool key_start= TRUE; KEY_PART_INFO* key_part_info= (KEY_PART_INFO*) alloc_root(&mem_root, sizeof(KEY_PART_INFO)*key_parts); |