diff --git a/mysql-test/r/partition.result b/mysql-test/r/partition.result index 2d54a66fe1190de23c65bc3d835830c8d2306152..6611d39628f201d8b44a9fb89ecf93bbdcff0ad7 100644 --- a/mysql-test/r/partition.result +++ b/mysql-test/r/partition.result @@ -50,6 +50,21 @@ t1 CREATE TABLE `t1` ( PARTITION p3 VALUES LESS THAN (733969) ENGINE = MyISAM, PARTITION pmax VALUES LESS THAN MAXVALUE ENGINE = MyISAM) */ DROP TABLE t1; +create table t1 (a int, b int, key(a)) +partition by list (a) +( partition p0 values in (1), +partition p1 values in (2)); +insert into t1 values (1,1),(2,1),(2,2),(2,3); +show indexes from t1; +Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment +t1 1 a 1 a A NULL NULL NULL YES BTREE +analyze table t1; +Table Op Msg_type Msg_text +test.t1 analyze status OK +show indexes from t1; +Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment +t1 1 a 1 a A 1 NULL NULL YES BTREE +drop table t1; CREATE TABLE t1 (a INT, FOREIGN KEY (a) REFERENCES t0 (a)) ENGINE=MyISAM PARTITION BY HASH (a); diff --git a/mysql-test/t/partition.test b/mysql-test/t/partition.test index c5ed098b6784be1b1e4faaf06dd336b071c4d3cb..1dfc53c6232c5dc2deb2059d189c17cb55693851 100644 --- a/mysql-test/t/partition.test +++ b/mysql-test/t/partition.test @@ -61,6 +61,19 @@ SELECT * FROM t1; SHOW CREATE TABLE t1; DROP TABLE t1; +# +# Bug#44059: rec_per_key on empty partition gives weird optimiser results +# +create table t1 (a int, b int, key(a)) +partition by list (a) +( partition p0 values in (1), + partition p1 values in (2)); +insert into t1 values (1,1),(2,1),(2,2),(2,3); +show indexes from t1; +analyze table t1; +show indexes from t1; +drop table t1; + # # Bug#36001: Partitions: spelling and using some error messages # diff --git a/sql/ha_partition.cc b/sql/ha_partition.cc index df5badccb1e407d9b522172acb325ad3ca427800..ac55c4e718e35fb4d81d32634953171eb53ec3ed 100644 --- a/sql/ha_partition.cc +++ b/sql/ha_partition.cc @@ -5011,8 +5011,9 @@ int ha_partition::info(uint flag) If the handler doesn't support statistics, it should set all of the above to 0. - We will allow the first handler to set the rec_per_key and use - this as an estimate on the total table. + We first scans through all partitions to get the one holding most rows. + We will then allow the handler with the most rows to set + the rec_per_key and use this as an estimate on the total table. max_data_file_length: Maximum data file length We ignore it, is only used in @@ -5024,14 +5025,33 @@ int ha_partition::info(uint flag) ref_length: We set this to the value calculated and stored in local object create_time: Creation time of table - Set by first handler - So we calculate these constants by using the variables on the first - handler. + So we calculate these constants by using the variables from the + handler with most rows. */ - handler *file; + handler *file, **file_array; + ulonglong max_records= 0; + uint32 i= 0; + uint32 handler_instance= 0; + + file_array= m_file; + do + { + file= *file_array; + /* Get variables if not already done */ + if (!(flag & HA_STATUS_VARIABLE) || + !bitmap_is_set(&(m_part_info->used_partitions), + (file_array - m_file))) + file->info(HA_STATUS_VARIABLE); + if (file->stats.records > max_records) + { + max_records= file->stats.records; + handler_instance= i; + } + i++; + } while (*(++file_array)); - file= m_file[0]; + file= m_file[handler_instance]; file->info(HA_STATUS_CONST); stats.create_time= file->stats.create_time; ref_length= m_ref_length;