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Fixed the bug that caused displaying incorrect values in

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the column cardinality of the table information_schema.statistics.
This commit is contained in:
Igor Babaev
2012-05-17 16:54:26 -07:00
parent 2a1afc29f2
commit 9b79feba56
5 changed files with 92 additions and 2 deletions
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35
mysql-test/r/stat_tables.result
View File

@@ -118,6 +118,41 @@ dbt3_s001 partsupp i_ps_suppkey 1 70
dbt3_s001 region PRIMARY 1 1
dbt3_s001 supplier PRIMARY 1 1
dbt3_s001 supplier i_s_nationkey 1 1.1111111111111112
select * from mysql.table_stat where table_name='orders';
db_name table_name cardinality
dbt3_s001 orders 1500
select * from mysql.index_stat where table_name='orders';
db_name table_name index_name prefix_arity avg_frequency
dbt3_s001 orders PRIMARY 1 1
dbt3_s001 orders i_o_orderdate 1 1.3321492007104796
dbt3_s001 orders i_o_custkey 1 15
select (select cardinality from mysql.table_stat where table_name='orders') /
(select avg_frequency from mysql.index_stat
where index_name='i_o_orderdate' and prefix_arity=1) as n_distinct;
n_distinct
1126
select count(distinct o_orderdate) from orders;
count(distinct o_orderdate)
1126
select (select cardinality from mysql.table_stat where table_name='orders') /
(select avg_frequency from mysql.index_stat
where index_name='i_o_custkey' and prefix_arity=1) as n_distinct;
n_distinct
100
select count(distinct o_custkey) from orders;
count(distinct o_custkey)
100
show index from orders;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
orders 0 PRIMARY 1 o_orderkey A 1500 NULL NULL BTREE
orders 1 i_o_orderdate 1 o_orderDATE A 1127 NULL NULL YES BTREE
orders 1 i_o_custkey 1 o_custkey A 100 NULL NULL YES BTREE
select index_name, column_name, cardinality from information_schema.statistics
where table_name='orders';
index_name column_name cardinality
PRIMARY o_orderkey 1500
i_o_orderdate o_orderDATE 1127
i_o_custkey o_custkey 100
set @save_optimizer_switch=@@optimizer_switch;
set optimizer_switch='index_condition_pushdown=off';
EXPLAIN select n_name, sum(l_extendedprice * (1 - l_discount)) as revenue

37
mysql-test/r/stat_tables_innodb.result
View File

@@ -143,6 +143,43 @@ dbt3_s001 region PRIMARY 1 1
dbt3_s001 supplier PRIMARY 1 1
dbt3_s001 supplier i_s_nationkey 1 1.1111111111111112
dbt3_s001 supplier i_s_nationkey 2 1
select * from mysql.table_stat where table_name='orders';
db_name table_name cardinality
dbt3_s001 orders 1500
select * from mysql.index_stat where table_name='orders';
db_name table_name index_name prefix_arity avg_frequency
dbt3_s001 orders PRIMARY 1 1
dbt3_s001 orders i_o_orderdate 1 1.3321492007104796
dbt3_s001 orders i_o_orderdate 2 1
dbt3_s001 orders i_o_custkey 1 15
dbt3_s001 orders i_o_custkey 2 1
select (select cardinality from mysql.table_stat where table_name='orders') /
(select avg_frequency from mysql.index_stat
where index_name='i_o_orderdate' and prefix_arity=1) as n_distinct;
n_distinct
1126
select count(distinct o_orderdate) from orders;
count(distinct o_orderdate)
1126
select (select cardinality from mysql.table_stat where table_name='orders') /
(select avg_frequency from mysql.index_stat
where index_name='i_o_custkey' and prefix_arity=1) as n_distinct;
n_distinct
100
select count(distinct o_custkey) from orders;
count(distinct o_custkey)
100
show index from orders;
Table Non_unique Key_name Seq_in_index Column_name Collation Cardinality Sub_part Packed Null Index_type Comment Index_comment
orders 0 PRIMARY 1 o_orderkey A 1500 NULL NULL BTREE
orders 1 i_o_orderdate 1 o_orderDATE A 1127 NULL NULL YES BTREE
orders 1 i_o_custkey 1 o_custkey A 100 NULL NULL YES BTREE
select index_name, column_name, cardinality from information_schema.statistics
where table_name='orders';
index_name column_name cardinality
PRIMARY o_orderkey 1500
i_o_orderdate o_orderDATE 1127
i_o_custkey o_custkey 100
set @save_optimizer_switch=@@optimizer_switch;
set optimizer_switch='index_condition_pushdown=off';
EXPLAIN select n_name, sum(l_extendedprice * (1 - l_discount)) as revenue

14
mysql-test/t/stat_tables.test
View File

@@ -69,6 +69,20 @@ FLUSH TABLE mysql.table_stat, mysql.index_stat;
select * from mysql.table_stat;
select * from mysql.index_stat;
select * from mysql.table_stat where table_name='orders';
select * from mysql.index_stat where table_name='orders';
select (select cardinality from mysql.table_stat where table_name='orders') /
(select avg_frequency from mysql.index_stat
where index_name='i_o_orderdate' and prefix_arity=1) as n_distinct;
select count(distinct o_orderdate) from orders;
select (select cardinality from mysql.table_stat where table_name='orders') /
(select avg_frequency from mysql.index_stat
where index_name='i_o_custkey' and prefix_arity=1) as n_distinct;
select count(distinct o_custkey) from orders;
show index from orders;
select index_name, column_name, cardinality from information_schema.statistics
where table_name='orders';
set @save_optimizer_switch=@@optimizer_switch;
set optimizer_switch='index_condition_pushdown=off';

1
sql/sql_select.cc
View File

@@ -14102,6 +14102,7 @@ create_tmp_table(THD *thd, TMP_TABLE_PARAM *param, List<Item> &fields,
table->intersect_keys.init();
table->keys_in_use_for_query.init();
table->no_rows_with_nulls= param->force_not_null_cols;
table->read_stat.cardinality_is_null= TRUE;
table->s= share;
init_tmp_table_share(thd, share, "", 0, tmpname, tmpname);

7
sql/sql_show.cc
View File

@@ -5441,9 +5441,12 @@ static int get_schema_stat_record(THD *thd, TABLE_LIST *tables,
TABLE *show_table= tables->table;
KEY *key_info=show_table->s->key_info;
if (show_table->file)
{
show_table->file->info(HA_STATUS_VARIABLE |
HA_STATUS_NO_LOCK |
HA_STATUS_TIME);
set_statistics_for_table(thd, show_table);
}
for (uint i=0 ; i < show_table->s->keys ; i++,key_info++)
{
KEY_PART_INFO *key_part= key_info->key_part;
@@ -5474,8 +5477,8 @@ static int get_schema_stat_record(THD *thd, TABLE_LIST *tables,
KEY *key=show_table->key_info+i;
if (key->rec_per_key[j])
{
ha_rows records=(show_table->file->stats.records /
key->rec_per_key[j]);
ha_rows records=((double) show_table->stat_records() /
key->real_rec_per_key(j));
table->field[9]->store((longlong) records, TRUE);
table->field[9]->set_notnull();
}