select @@global.use_stat_tables; @@global.use_stat_tables COMPLEMENTARY select @@session.use_stat_tables; @@session.use_stat_tables COMPLEMENTARY set @save_use_stat_tables=@@use_stat_tables; set use_stat_tables='preferably'; DROP DATABASE IF EXISTS dbt3_s001; CREATE DATABASE dbt3_s001; use dbt3_s001; set @save_optimizer_switch=@@optimizer_switch; set optimizer_switch='extended_keys=off'; select * from mysql.table_stats; db_name table_name cardinality dbt3_s001 customer 150 dbt3_s001 lineitem 6005 dbt3_s001 nation 25 dbt3_s001 orders 1500 dbt3_s001 part 200 dbt3_s001 partsupp 700 dbt3_s001 region 5 dbt3_s001 supplier 10 select * from mysql.index_stats; db_name table_name index_name prefix_arity avg_frequency dbt3_s001 customer PRIMARY 1 1.0000 dbt3_s001 customer i_c_nationkey 1 6.0000 dbt3_s001 lineitem PRIMARY 1 4.0033 dbt3_s001 lineitem PRIMARY 2 1.0000 dbt3_s001 lineitem i_l_shipdate 1 2.6500 dbt3_s001 lineitem i_l_suppkey_partkey 1 30.0250 dbt3_s001 lineitem i_l_suppkey_partkey 2 8.5786 dbt3_s001 lineitem i_l_partkey 1 30.0250 dbt3_s001 lineitem i_l_suppkey 1 600.5000 dbt3_s001 lineitem i_l_receiptdate 1 2.6477 dbt3_s001 lineitem i_l_orderkey 1 4.0033 dbt3_s001 lineitem i_l_orderkey_quantity 1 4.0033 dbt3_s001 lineitem i_l_orderkey_quantity 2 1.0404 dbt3_s001 lineitem i_l_commitdate 1 2.7160 dbt3_s001 nation PRIMARY 1 1.0000 dbt3_s001 nation i_n_regionkey 1 5.0000 dbt3_s001 orders PRIMARY 1 1.0000 dbt3_s001 orders i_o_orderdate 1 1.3321 dbt3_s001 orders i_o_custkey 1 15.0000 dbt3_s001 part PRIMARY 1 1.0000 dbt3_s001 part i_p_retailprice 1 1.0000 dbt3_s001 partsupp PRIMARY 1 3.5000 dbt3_s001 partsupp PRIMARY 2 1.0000 dbt3_s001 partsupp i_ps_partkey 1 3.5000 dbt3_s001 partsupp i_ps_suppkey 1 70.0000 dbt3_s001 region PRIMARY 1 1.0000 dbt3_s001 supplier PRIMARY 1 1.0000 dbt3_s001 supplier i_s_nationkey 1 1.1111 set optimizer_switch=@save_optimizer_switch; 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 from customer, orders, lineitem, supplier, nation, region where c_custkey = o_custkey and l_orderkey = o_orderkey and l_suppkey = s_suppkey and c_nationkey = s_nationkey and s_nationkey = n_nationkey and n_regionkey = r_regionkey and r_name = 'AMERICA' and o_orderdate >= date '1995-01-01' and o_orderdate < date '1995-01-01' + interval '1' year group by n_name order by revenue desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE orders range PRIMARY,i_o_orderdate,i_o_custkey i_o_orderdate 4 NULL 179 Using where; Using temporary; Using filesort 1 SIMPLE customer eq_ref PRIMARY,i_c_nationkey PRIMARY 4 dbt3_s001.orders.o_custkey 1 Using where 1 SIMPLE nation eq_ref PRIMARY,i_n_regionkey PRIMARY 4 dbt3_s001.customer.c_nationkey 1 1 SIMPLE region ALL PRIMARY NULL NULL NULL 5 Using where; Using join buffer (flat, BNL join) 1 SIMPLE lineitem ref PRIMARY,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity PRIMARY 4 dbt3_s001.orders.o_orderkey 4 Using where 1 SIMPLE supplier eq_ref PRIMARY,i_s_nationkey PRIMARY 4 dbt3_s001.lineitem.l_suppkey 1 Using where select n_name, sum(l_extendedprice * (1 - l_discount)) as revenue from customer, orders, lineitem, supplier, nation, region where c_custkey = o_custkey and l_orderkey = o_orderkey and l_suppkey = s_suppkey and c_nationkey = s_nationkey and s_nationkey = n_nationkey and n_regionkey = r_regionkey and r_name = 'AMERICA' and o_orderdate >= date '1995-01-01' and o_orderdate < date '1995-01-01' + interval '1' year group by n_name order by revenue desc; n_name revenue PERU 321915.8715 ARGENTINA 69817.1451 set optimizer_switch=@save_optimizer_switch; delete from mysql.index_stats; select * from mysql.table_stats; db_name table_name cardinality dbt3_s001 customer 150 dbt3_s001 lineitem 6005 dbt3_s001 nation 25 dbt3_s001 orders 1500 dbt3_s001 part 200 dbt3_s001 partsupp 700 dbt3_s001 region 5 dbt3_s001 supplier 10 select * from mysql.index_stats; db_name table_name index_name prefix_arity avg_frequency dbt3_s001 customer PRIMARY 1 1.0000 dbt3_s001 customer i_c_nationkey 1 6.0000 dbt3_s001 lineitem PRIMARY 1 4.0033 dbt3_s001 lineitem PRIMARY 2 1.0000 dbt3_s001 lineitem i_l_shipdate 1 2.6500 dbt3_s001 lineitem i_l_suppkey_partkey 1 30.0250 dbt3_s001 lineitem i_l_suppkey_partkey 2 8.5786 dbt3_s001 lineitem i_l_partkey 1 30.0250 dbt3_s001 lineitem i_l_suppkey 1 600.5000 dbt3_s001 lineitem i_l_receiptdate 1 2.6477 dbt3_s001 lineitem i_l_orderkey 1 4.0033 dbt3_s001 lineitem i_l_orderkey_quantity 1 4.0033 dbt3_s001 lineitem i_l_orderkey_quantity 2 1.0404 dbt3_s001 lineitem i_l_commitdate 1 2.7160 dbt3_s001 nation PRIMARY 1 1.0000 dbt3_s001 nation i_n_regionkey 1 5.0000 dbt3_s001 orders PRIMARY 1 1.0000 dbt3_s001 orders i_o_orderdate 1 1.3321 dbt3_s001 orders i_o_custkey 1 15.0000 dbt3_s001 part PRIMARY 1 1.0000 dbt3_s001 part i_p_retailprice 1 1.0000 dbt3_s001 partsupp PRIMARY 1 3.5000 dbt3_s001 partsupp PRIMARY 2 1.0000 dbt3_s001 partsupp i_ps_partkey 1 3.5000 dbt3_s001 partsupp i_ps_suppkey 1 70.0000 dbt3_s001 region PRIMARY 1 1.0000 dbt3_s001 supplier PRIMARY 1 1.0000 dbt3_s001 supplier i_s_nationkey 1 1.1111 select * from mysql.table_stats where table_name='orders'; db_name table_name cardinality dbt3_s001 orders 1500 select * from mysql.index_stats where table_name='orders'; db_name table_name index_name prefix_arity avg_frequency dbt3_s001 orders PRIMARY 1 1.0000 dbt3_s001 orders i_o_orderdate 1 1.3321 dbt3_s001 orders i_o_custkey 1 15.0000 select (select cardinality from mysql.table_stats where table_name='orders') / (select avg_frequency from mysql.index_stats where index_name='i_o_orderdate' and prefix_arity=1) as n_distinct; n_distinct 1126.0416 select count(distinct o_orderdate) from orders; count(distinct o_orderdate) 1126 select (select cardinality from mysql.table_stats where table_name='orders') / (select avg_frequency from mysql.index_stats where index_name='i_o_custkey' and prefix_arity=1) as n_distinct; n_distinct 100.0000 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 1126 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 1126 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 from customer, orders, lineitem, supplier, nation, region where c_custkey = o_custkey and l_orderkey = o_orderkey and l_suppkey = s_suppkey and c_nationkey = s_nationkey and s_nationkey = n_nationkey and n_regionkey = r_regionkey and r_name = 'AMERICA' and o_orderdate >= date '1995-01-01' and o_orderdate < date '1995-01-01' + interval '1' year group by n_name order by revenue desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE orders range PRIMARY,i_o_orderdate,i_o_custkey i_o_orderdate 4 NULL 179 Using where; Using temporary; Using filesort 1 SIMPLE customer eq_ref PRIMARY,i_c_nationkey PRIMARY 4 dbt3_s001.orders.o_custkey 1 Using where 1 SIMPLE nation eq_ref PRIMARY,i_n_regionkey PRIMARY 4 dbt3_s001.customer.c_nationkey 1 1 SIMPLE region ALL PRIMARY NULL NULL NULL 5 Using where; Using join buffer (flat, BNL join) 1 SIMPLE lineitem ref PRIMARY,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity PRIMARY 4 dbt3_s001.orders.o_orderkey 4 Using where 1 SIMPLE supplier eq_ref PRIMARY,i_s_nationkey PRIMARY 4 dbt3_s001.lineitem.l_suppkey 1 Using where select n_name, sum(l_extendedprice * (1 - l_discount)) as revenue from customer, orders, lineitem, supplier, nation, region where c_custkey = o_custkey and l_orderkey = o_orderkey and l_suppkey = s_suppkey and c_nationkey = s_nationkey and s_nationkey = n_nationkey and n_regionkey = r_regionkey and r_name = 'AMERICA' and o_orderdate >= date '1995-01-01' and o_orderdate < date '1995-01-01' + interval '1' year group by n_name order by revenue desc; n_name revenue PERU 321915.8715 ARGENTINA 69817.1451 set optimizer_switch=@save_optimizer_switch; EXPLAIN select o_year, sum(case when nation = 'UNITED STATES' then volume else 0 end) / sum(volume) as mkt_share from (select extract(year from o_orderdate) as o_year, l_extendedprice * (1-l_discount) as volume, n2.n_name as nation from part, supplier, lineitem, orders, customer, nation n1, nation n2, region where p_partkey = l_partkey and s_suppkey = l_suppkey and l_orderkey = o_orderkey and o_custkey = c_custkey and c_nationkey = n1.n_nationkey and n1.n_regionkey = r_regionkey and r_name = 'AMERICA' and s_nationkey = n2.n_nationkey and o_orderdate between date '1995-01-01' and date '1996-12-31' and p_type = 'STANDARD BRUSHED STEEL' ) as all_nations group by o_year order by o_year; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE orders ALL PRIMARY,i_o_orderdate,i_o_custkey NULL NULL NULL 1500 Using where; Using temporary; Using filesort 1 SIMPLE customer eq_ref PRIMARY,i_c_nationkey PRIMARY 4 dbt3_s001.orders.o_custkey 1 Using where 1 SIMPLE n1 eq_ref PRIMARY,i_n_regionkey PRIMARY 4 dbt3_s001.customer.c_nationkey 1 1 SIMPLE region ALL PRIMARY NULL NULL NULL 5 Using where; Using join buffer (flat, BNL join) 1 SIMPLE lineitem ref PRIMARY,i_l_suppkey_partkey,i_l_partkey,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity PRIMARY 4 dbt3_s001.orders.o_orderkey 4 Using where 1 SIMPLE part eq_ref PRIMARY PRIMARY 4 dbt3_s001.lineitem.l_partkey 1 Using where 1 SIMPLE supplier eq_ref PRIMARY,i_s_nationkey PRIMARY 4 dbt3_s001.lineitem.l_suppkey 1 Using where 1 SIMPLE n2 eq_ref PRIMARY PRIMARY 4 dbt3_s001.supplier.s_nationkey 1 select o_year, sum(case when nation = 'UNITED STATES' then volume else 0 end) / sum(volume) as mkt_share from (select extract(year from o_orderdate) as o_year, l_extendedprice * (1-l_discount) as volume, n2.n_name as nation from part, supplier, lineitem, orders, customer, nation n1, nation n2, region where p_partkey = l_partkey and s_suppkey = l_suppkey and l_orderkey = o_orderkey and o_custkey = c_custkey and c_nationkey = n1.n_nationkey and n1.n_regionkey = r_regionkey and r_name = 'AMERICA' and s_nationkey = n2.n_nationkey and o_orderdate between date '1995-01-01' and date '1996-12-31' and p_type = 'STANDARD BRUSHED STEEL' ) as all_nations group by o_year order by o_year; o_year mkt_share 1995 0.4495521838895718 1996 0.024585468215352495 EXPLAIN select nation, o_year, sum(amount) as sum_profit from (select n_name as nation, extract(year from o_orderdate) as o_year, l_extendedprice * (1 - l_discount) - ps_supplycost * l_quantity as amount from part, supplier, lineitem, partsupp, orders, nation where s_suppkey = l_suppkey and ps_suppkey = l_suppkey and ps_partkey = l_partkey and p_partkey = l_partkey and o_orderkey = l_orderkey and s_nationkey = n_nationkey and p_name like '%green%') as profit group by nation, o_year order by nation, o_year desc; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE supplier ALL PRIMARY,i_s_nationkey NULL NULL NULL 10 Using where; Using temporary; Using filesort 1 SIMPLE nation eq_ref PRIMARY PRIMARY 4 dbt3_s001.supplier.s_nationkey 1 1 SIMPLE partsupp ref PRIMARY,i_ps_partkey,i_ps_suppkey i_ps_suppkey 4 dbt3_s001.supplier.s_suppkey 70 1 SIMPLE part eq_ref PRIMARY PRIMARY 4 dbt3_s001.partsupp.ps_partkey 1 Using where 1 SIMPLE lineitem ref PRIMARY,i_l_suppkey_partkey,i_l_partkey,i_l_suppkey,i_l_orderkey,i_l_orderkey_quantity i_l_suppkey_partkey 10 dbt3_s001.partsupp.ps_partkey,dbt3_s001.supplier.s_suppkey 8 1 SIMPLE orders eq_ref PRIMARY PRIMARY 4 dbt3_s001.lineitem.l_orderkey 1 select nation, o_year, sum(amount) as sum_profit from (select n_name as nation, extract(year from o_orderdate) as o_year, l_extendedprice * (1 - l_discount) - ps_supplycost * l_quantity as amount from part, supplier, lineitem, partsupp, orders, nation where s_suppkey = l_suppkey and ps_suppkey = l_suppkey and ps_partkey = l_partkey and p_partkey = l_partkey and o_orderkey = l_orderkey and s_nationkey = n_nationkey and p_name like '%green%') as profit group by nation, o_year order by nation, o_year desc; nation o_year sum_profit ARGENTINA 1997 18247.873399999993 ARGENTINA 1996 7731.089399999995 ARGENTINA 1995 134490.5697 ARGENTINA 1994 36767.101500000004 ARGENTINA 1993 35857.08 ARGENTINA 1992 35740 ETHIOPIA 1998 2758.7801999999992 ETHIOPIA 1997 19419.294599999997 ETHIOPIA 1995 51231.87439999999 ETHIOPIA 1994 3578.9478999999974 ETHIOPIA 1992 1525.8234999999986 IRAN 1998 37817.229600000006 IRAN 1997 52643.77359999999 IRAN 1996 70143.7761 IRAN 1995 84094.58260000001 IRAN 1994 18140.925599999995 IRAN 1993 78655.1676 IRAN 1992 87142.23960000002 IRAQ 1998 22860.8082 IRAQ 1997 93676.24359999999 IRAQ 1996 45103.3242 IRAQ 1994 36010.728599999995 IRAQ 1993 33221.9399 IRAQ 1992 47755.05900000001 KENYA 1998 44194.831999999995 KENYA 1997 57578.36259999999 KENYA 1996 59195.90210000001 KENYA 1995 79262.6278 KENYA 1994 102360.66609999999 KENYA 1993 128422.0196 KENYA 1992 181517.2089 MOROCCO 1998 41797.823199999984 MOROCCO 1997 23685.801799999994 MOROCCO 1996 62115.19579999998 MOROCCO 1995 42442.64300000001 MOROCCO 1994 48655.878000000004 MOROCCO 1993 22926.744400000003 MOROCCO 1992 32239.8088 PERU 1998 86999.36459999997 PERU 1997 121110.41070000001 PERU 1996 177040.40759999995 PERU 1995 122247.94520000002 PERU 1994 88046.25329999998 PERU 1993 49379.813799999996 PERU 1992 80646.86050000001 UNITED KINGDOM 1998 50577.25560000001 UNITED KINGDOM 1997 114288.8605 UNITED KINGDOM 1996 147684.46480000002 UNITED KINGDOM 1995 225267.65759999998 UNITED KINGDOM 1994 140595.5864 UNITED KINGDOM 1993 322548.49210000003 UNITED KINGDOM 1992 67747.88279999999 UNITED STATES 1998 3957.0431999999996 UNITED STATES 1997 94729.5704 UNITED STATES 1996 79297.85670000002 UNITED STATES 1995 62201.23360000001 UNITED STATES 1994 43075.629899999985 UNITED STATES 1993 27168.486199999996 UNITED STATES 1992 34092.366 set @save_optimizer_switch=@@optimizer_switch; set optimizer_switch='extended_keys=on'; EXPLAIN select o_orderkey, p_partkey from part, lineitem, orders where p_retailprice > 1100 and o_orderdate='1997-01-01' and o_orderkey=l_orderkey and p_partkey=l_partkey; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE orders ref PRIMARY,i_o_orderdate i_o_orderdate 4 const 1 1 SIMPLE lineitem ref PRIMARY,i_l_suppkey_partkey,i_l_partkey,i_l_orderkey,i_l_orderkey_quantity PRIMARY 4 dbt3_s001.orders.o_orderkey 4 Using where 1 SIMPLE part eq_ref PRIMARY,i_p_retailprice PRIMARY 4 dbt3_s001.lineitem.l_partkey 1 Using where select o_orderkey, p_partkey from part, lineitem, orders where p_retailprice > 1100 and o_orderdate='1997-01-01' and o_orderkey=l_orderkey and p_partkey=l_partkey; o_orderkey p_partkey 5895 200 set optimizer_switch=@save_optimizer_switch; DROP DATABASE dbt3_s001; use test; # # Bug mdev-473: ANALYZE table locked for write # set use_stat_tables='complementary'; create table t1 (i int); lock table t1 write; analyze table t1; Table Op Msg_type Msg_text test.t1 analyze status Engine-independent statistics collected test.t1 analyze status Table is already up to date alter table t1 add column a varchar(8); drop table t1; # # Bug mdev-487: memory leak in ANALYZE with stat tables # SET use_stat_tables = 'preferably'; CREATE TABLE t1 (a INT); INSERT INTO t1 VALUES (1),(2); DELETE FROM t1 WHERE a=1; ANALYZE TABLE t1; Table Op Msg_type Msg_text test.t1 analyze status Engine-independent statistics collected test.t1 analyze status OK DROP TABLE t1; # # Bug mdev-518: corrupted/missing statistical tables # CREATE TABLE t1 (i int) ENGINE=MyISAM; INSERT INTO t1 VALUES (1),(2); FLUSH TABLE t1; SET use_stat_tables='never'; EXPLAIN SELECT * FROM t1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 2 FLUSH TABLES; SET use_stat_tables='preferably'; EXPLAIN SELECT * FROM t1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 ALL NULL NULL NULL NULL 2 DROP TABLE t1; set use_stat_tables=@save_use_stat_tables; # # Bug mdev-5204: invalid impossible where after reading const tables # when use_stat_tables = 'preferably' # set use_stat_tables = 'preferably'; CREATE TABLE t1 (id int PRIMARY KEY) ENGINE=MyISAM; INSERT INTO t1 VALUES (1),(2); ANALYZE TABLE t1; Table Op Msg_type Msg_text test.t1 analyze status Engine-independent statistics collected test.t1 analyze status OK CREATE TABLE t2 (name char(3)) ENGINE=MyISAM; ANALYZE TABLE t2; Table Op Msg_type Msg_text test.t2 analyze status Engine-independent statistics collected test.t2 analyze status Table is already up to date INSERT INTO t2 VALUES ('USA'),('AUS'); SELECT * FROM t1 STRAIGHT_JOIN t2 WHERE name IN ( 'AUS','YEM' ) AND id = 1; id name 1 AUS EXPLAIN SELECT * FROM t1 STRAIGHT_JOIN t2 WHERE name IN ( 'AUS','YEM' ) AND id = 1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1 Using index 1 SIMPLE t2 ALL NULL NULL NULL NULL 0 Using where ANALYZE TABLE t2; Table Op Msg_type Msg_text test.t2 analyze status Engine-independent statistics collected test.t2 analyze status OK SELECT * FROM t1 STRAIGHT_JOIN t2 WHERE name IN ( 'AUS','YEM' ) AND id = 1; id name 1 AUS EXPLAIN SELECT * FROM t1 STRAIGHT_JOIN t2 WHERE name IN ( 'AUS','YEM' ) AND id = 1; id select_type table type possible_keys key key_len ref rows Extra 1 SIMPLE t1 const PRIMARY PRIMARY 4 const 1 Using index 1 SIMPLE t2 ALL NULL NULL NULL NULL 2 Using where DROP TABLE t1,t2; # # MDEV-7370: Server deadlocks on renaming a table for which persistent statistics exists # drop database if exists db1; drop database if exists db1; create database db1; create database db2; use db1; # # First, run the original testcase: # create table t1 (i int); insert into t1 values (10),(20); analyze table t1 persistent for all; Table Op Msg_type Msg_text db1.t1 analyze status Engine-independent statistics collected db1.t1 analyze status OK rename table t1 to db2.t1; # Verify that stats in the old database are gone: select * from mysql.column_stats where db_name='db1' and table_name='t1'; db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram select * from mysql.table_stats where db_name='db1' and table_name='t1'; db_name table_name cardinality # Verify that stats are present in the new database: select * from mysql.column_stats where db_name='db2' and table_name='t1'; db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram db2 t1 i 10 20 0.0000 4.0000 1.0000 0 NULL NULL select * from mysql.table_stats where db_name='db2' and table_name='t1'; db_name table_name cardinality db2 t1 2 # # Now, try with more than one column and with indexes: # use test; create table t1(a int primary key); insert into t1 values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9); use db1; create table t2 (a int, b int, c int, key IDX1(a), key IDX2(a,b)); insert into t2 select a/10, a/2, a from test.t1; analyze table t2 persistent for all; Table Op Msg_type Msg_text db1.t2 analyze status Engine-independent statistics collected db1.t2 analyze status Table is already up to date alter table t2 rename db2.t2; # Verify that stats in the old database are gone: select * from mysql.table_stats where db_name='db1' and table_name='t2'; db_name table_name cardinality select * from mysql.column_stats where db_name='db1' and table_name='t2'; db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram select * from mysql.index_stats where db_name='db1' and table_name='t2'; db_name table_name index_name prefix_arity avg_frequency # Verify that stats are present in the new database: select * from mysql.table_stats where db_name='db2' and table_name='t2'; db_name table_name cardinality db2 t2 10 select * from mysql.column_stats where db_name='db2' and table_name='t2'; db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram db2 t2 a 0 1 0.0000 4.0000 5.0000 0 NULL NULL db2 t2 b 0 5 0.0000 4.0000 1.6667 0 NULL NULL db2 t2 c 0 9 0.0000 4.0000 1.0000 0 NULL NULL select * from mysql.index_stats where db_name='db2' and table_name='t2'; db_name table_name index_name prefix_arity avg_frequency db2 t2 IDX1 1 5.0000 db2 t2 IDX2 1 5.0000 db2 t2 IDX2 2 1.6667 use db2; # # Now, rename within the same database and verify: # rename table t2 to t3; # No stats under old name: select * from mysql.table_stats where db_name='db2' and table_name='t2'; db_name table_name cardinality select * from mysql.column_stats where db_name='db2' and table_name='t2'; db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram select * from mysql.index_stats where db_name='db2' and table_name='t2'; db_name table_name index_name prefix_arity avg_frequency # Stats under the new name: select * from mysql.table_stats where db_name='db2' and table_name='t3'; db_name table_name cardinality db2 t3 10 select * from mysql.column_stats where db_name='db2' and table_name='t3'; db_name table_name column_name min_value max_value nulls_ratio avg_length avg_frequency hist_size hist_type histogram db2 t3 a 0 1 0.0000 4.0000 5.0000 0 NULL NULL db2 t3 b 0 5 0.0000 4.0000 1.6667 0 NULL NULL db2 t3 c 0 9 0.0000 4.0000 1.0000 0 NULL NULL select * from mysql.index_stats where db_name='db2' and table_name='t3'; db_name table_name index_name prefix_arity avg_frequency db2 t3 IDX1 1 5.0000 db2 t3 IDX2 1 5.0000 db2 t3 IDX2 2 1.6667 use test; drop database db1; drop database db2; drop table t1; set use_stat_tables=@save_use_stat_tables;