diff options
Diffstat (limited to 'sql/sql_select.h')
| -rw-r--r-- | sql/sql_select.h | 78 |
1 files changed, 63 insertions, 15 deletions
diff --git a/sql/sql_select.h b/sql/sql_select.h index ccdd66d5b95..6ab4463605b 100644 --- a/sql/sql_select.h +++ b/sql/sql_select.h @@ -57,16 +57,16 @@ typedef struct st_table_ref */ key_part_map null_rejecting; table_map depend_map; // Table depends on these tables. - byte *null_ref_key; // null byte position in the key_buf. - // used for REF_OR_NULL optimization. + /* null byte position in the key_buf. Used for REF_OR_NULL optimization */ + byte *null_ref_key; } TABLE_REF; + /* -** CACHE_FIELD and JOIN_CACHE is used on full join to cache records in outer -** table + CACHE_FIELD and JOIN_CACHE is used on full join to cache records in outer + table */ - typedef struct st_cache_field { char *str; uint length,blob_length; @@ -84,7 +84,7 @@ typedef struct st_join_cache { /* -** The structs which holds the join connections and join states + The structs which holds the join connections and join states */ enum join_type { JT_UNKNOWN,JT_SYSTEM,JT_CONST,JT_EQ_REF,JT_REF,JT_MAYBE_REF, JT_ALL, JT_RANGE, JT_NEXT, JT_FT, JT_REF_OR_NULL, @@ -104,6 +104,7 @@ typedef enum_nested_loop_state typedef int (*Read_record_func)(struct st_join_table *tab); Next_select_func setup_end_select_func(JOIN *join); + typedef struct st_join_table { st_join_table() {} /* Remove gcc warning */ TABLE *table; @@ -128,13 +129,28 @@ typedef struct st_join_table { key_map checked_keys; /* Keys checked in find_best */ key_map needed_reg; key_map keys; /* all keys with can be used */ - ha_rows records,found_records,read_time; + + /* Either #rows in the table or 1 for const table. */ + ha_rows records; + /* + Number of records that will be scanned (yes scanned, not returned) by the + best 'independent' access method, i.e. table scan or QUICK_*_SELECT) + */ + ha_rows found_records; + /* + Cost of accessing the table using "ALL" or range/index_merge access + method (but not 'index' for some reason), i.e. this matches method which + E(#records) is in found_records. + */ + ha_rows read_time; + table_map dependent,key_dependent; uint use_quick,index; uint status; // Save status for cache uint used_fields,used_fieldlength,used_blobs; enum join_type type; bool cached_eq_ref_table,eq_ref_table,not_used_in_distinct; + bool sorted; TABLE_REF ref; JOIN_CACHE cache; JOIN *join; @@ -155,15 +171,38 @@ enum_nested_loop_state sub_select_cache(JOIN *join, JOIN_TAB *join_tab, bool enum_nested_loop_state sub_select(JOIN *join,JOIN_TAB *join_tab, bool end_of_records); - -typedef struct st_position /* Used in find_best */ +/* + Information about a position of table within a join order. Used in join + optimization. +*/ +typedef struct st_position { + /* + The "fanout": number of output rows that will be produced (after + pushed down selection condition is applied) per each row combination of + previous tables. + */ double records_read; + + /* + Cost accessing the table in course of the entire complete join execution, + i.e. cost of one access method use (e.g. 'range' or 'ref' scan ) times + number the access method will be invoked. + */ double read_time; JOIN_TAB *table; + + /* + NULL - 'index' or 'range' or 'index_merge' or 'ALL' access is used. + Other - [eq_]ref[_or_null] access is used. Pointer to {t.keypart1 = expr} + */ KEYUSE *key; + + /* If ref-based access is used: bitmap of tables this table depends on */ + table_map ref_depend_map; } POSITION; + typedef struct st_rollup { enum State { STATE_NONE, STATE_INITED, STATE_READY }; @@ -462,12 +501,13 @@ public: store_key(THD *thd, Field *field_arg, char *ptr, char *null, uint length) :null_ptr(null), err(0), null_key(0) { - if (field_arg->type() == FIELD_TYPE_BLOB) + if (field_arg->type() == MYSQL_TYPE_BLOB) { - /* Key segments are always packed with a 2 byte length prefix */ - to_field=new Field_varstring(ptr, length, 2, (uchar*) null, 1, - Field::NONE, field_arg->field_name, - field_arg->table, field_arg->charset()); + /* Key segments are always packed with a 2 byte length prefix */ + to_field= new Field_varstring(ptr, length, 2, (uchar*) null, 1, + Field::NONE, field_arg->field_name, + field_arg->table->s, field_arg->charset()); + to_field->init(field_arg->table); } else to_field=field_arg->new_key_field(thd->mem_root, field_arg->table, @@ -497,7 +537,11 @@ class store_key_field: public store_key } enum store_key_result copy() { + TABLE *table= copy_field.to_field->table; + my_bitmap_map *old_map= dbug_tmp_use_all_columns(table, + table->write_set); copy_field.do_copy(©_field); + dbug_tmp_restore_column_map(table->write_set, old_map); null_key= to_field->is_null(); return err != 0 ? STORE_KEY_FATAL : STORE_KEY_OK; } @@ -518,7 +562,11 @@ public: {} enum store_key_result copy() { + TABLE *table= to_field->table; + my_bitmap_map *old_map= dbug_tmp_use_all_columns(table, + table->write_set); int res= item->save_in_field(to_field, 1); + dbug_tmp_restore_column_map(table->write_set, old_map); null_key= to_field->is_null() || item->null_value; return (err != 0 || res > 2 ? STORE_KEY_FATAL : (store_key_result) res); } @@ -556,7 +604,7 @@ public: const char *name() const { return "const"; } }; -bool cp_buffer_from_ref(THD *thd, TABLE_REF *ref); +bool cp_buffer_from_ref(THD *thd, TABLE *table, TABLE_REF *ref); bool error_if_full_join(JOIN *join); int report_error(TABLE *table, int error); int safe_index_read(JOIN_TAB *tab); |