diff options
Diffstat (limited to 'sql/sql_select.cc')
| -rw-r--r-- | sql/sql_select.cc | 62 |
1 files changed, 55 insertions, 7 deletions
diff --git a/sql/sql_select.cc b/sql/sql_select.cc index 127409a01bf..8b32ae47e3d 100644 --- a/sql/sql_select.cc +++ b/sql/sql_select.cc @@ -2074,6 +2074,7 @@ make_join_statistics(JOIN *join, TABLE_LIST *tables, COND *conds, s->key_dependent= 0; if (tables->schema_table) table->file->stats.records= 2; + table->quick_condition_rows= table->file->records(); s->on_expr_ref= &tables->on_expr; if (*s->on_expr_ref) @@ -3754,15 +3755,25 @@ best_access_path(JOIN *join, { // Check full join ha_rows rnd_records= s->found_records; /* - If there is a restriction on the table, assume that 25% of the - rows can be skipped on next part. - This is to force tables that this table depends on before this - table + If there is a filtering condition on the table (i.e. ref analyzer found + at least one "table.keyXpartY= exprZ", where exprZ refers only to tables + preceding this table in the join order we're now considering), then + assume that 25% of the rows will be filtered out by this condition. + + This heuristic is supposed to force tables used in exprZ to be before + this table in join order. */ if (found_constraint) rnd_records-= rnd_records/4; /* + If applicable, get a more accurate estimate. Don't use the two + heuristics at once. + */ + if (s->table->quick_condition_rows != s->found_records) + rnd_records= s->table->quick_condition_rows; + + /* Range optimizer never proposes a RANGE if it isn't better than FULL: so if RANGE is present, it's always preferred to FULL. Here we estimate its cost. @@ -3773,6 +3784,10 @@ best_access_path(JOIN *join, For each record we: - read record range through 'quick' - skip rows which does not satisfy WHERE constraints + TODO: + We take into account possible use of join cache for ALL/index + access (see first else-branch below), but we don't take it into + account here for range/index_merge access. Find out why this is so. */ tmp= record_count * (s->quick->read_time + @@ -4342,6 +4357,8 @@ best_extension_by_limited_search(JOIN *join, return; DBUG_ENTER("best_extension_by_limited_search"); + DBUG_EXECUTE("opt", print_plan(join, idx, read_time, record_count, idx, + "SOFAR:");); /* 'join' is a partial plan with lower cost than the best plan so far, @@ -14065,6 +14082,8 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, item_list.push_back(item_null); if (join->thd->lex->describe & DESCRIBE_PARTITIONS) item_list.push_back(item_null); + if (join->thd->lex->describe & DESCRIBE_EXTENDED) + item_list.push_back(item_null); item_list.push_back(new Item_string(message,strlen(message),cs)); if (result->send_data(item_list)) @@ -14110,6 +14129,9 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, } item_list.push_back(new Item_string(table_name_buffer, len, cs)); } + /* partitions */ + if (join->thd->lex->describe & DESCRIBE_PARTITIONS) + item_list.push_back(item_null); /* type */ item_list.push_back(new Item_string(join_type_str[JT_ALL], strlen(join_type_str[JT_ALL]), @@ -14122,6 +14144,9 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, item_list.push_back(item_null); /* ref */ item_list.push_back(item_null); + /* in_rows */ + if (join->thd->lex->describe & DESCRIBE_EXTENDED) + item_list.push_back(item_null); /* rows */ item_list.push_back(item_null); /* extra */ @@ -14277,10 +14302,33 @@ static void select_describe(JOIN *join, bool need_tmp_table, bool need_order, item_list.push_back(item_null); item_list.push_back(item_null); } + /* Add "rows" field to item_list. */ - item_list.push_back(new Item_int((longlong) (ulonglong) - join->best_positions[i]. records_read, - 21)); + ha_rows examined_rows; + if (tab->select && tab->select->quick) + examined_rows= tab->select->quick->records; + else if (tab->type == JT_NEXT || tab->type == JT_ALL) + examined_rows= tab->table->file->records(); + else + examined_rows=(ha_rows)join->best_positions[i].records_read; + + item_list.push_back(new Item_int((longlong) (ulonglong) examined_rows, + 21)); + + /* Add "filtered" field to item_list. */ + if (join->thd->lex->describe & DESCRIBE_EXTENDED) + { + Item_float *filtered; + float f; + if (examined_rows) + f= 100.0 * join->best_positions[i].records_read / examined_rows; + else + f= 0.0; + item_list.push_back((filtered= new Item_float(f))); + filtered->decimals= 2; + } + + /* Build "Extra" field and add it to item_list. */ my_bool key_read=table->key_read; if ((tab->type == JT_NEXT || tab->type == JT_CONST) && |