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9a4110aa57
The problem was an assignment in test_quick_select() that flagged empty tables with "Impossible where". This test was however wrong as it didn't work correctly for left join. Removed the test, but added checking of empty tables in DELETE and UPDATE to get similar EXPLAIN as before. The new tests is a bit more strict (better) than before as it catches all cases of empty tables in single table DELETE/UPDATE.
275 lines
11 KiB
Text
275 lines
11 KiB
Text
drop table if exists t0, t1;
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create table t0 (a int) engine=myisam;
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insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);
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#
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# Tests for single-table DELETE
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#
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explain select * from t0 where a=3;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
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explain delete from t0 where a=3;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
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# DELETE without WHERE is a special case:
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explain delete from t0;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL 8 Deleting all rows
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create table t1 (a int, b int, filler char(100), key(a), key(b));
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insert into t1
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select A.a+10*B.a + 10*C.a, A.a+10*B.a + 10*C.a, 'filler'
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from t0 A, t0 B, t0 C;
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# This should use an index, possible_keys=NULL because there is no WHERE
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explain delete from t1 order by a limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 index NULL a 5 NULL 2
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# This should use range, possible_keys={a,b}
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explain delete from t1 where a<20 and b < 10;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a,b a 5 NULL 1 Using where
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# This should use ALL + filesort
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explain delete from t1 order by a+1 limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 512 Using filesort
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# This should use range + using filesort
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explain delete from t1 where a<20 order by b limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a a 5 NULL 1 Using where; Using filesort
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# Try some subqueries:
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explain delete from t1 where a < (select max(a) from t0);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 range a a 5 NULL 1 Using where
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2 SUBQUERY t0 ALL NULL NULL NULL NULL 8
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explain delete from t1 where a < (select max(a) from t0 where a < t1.b);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 512 Using where
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2 DEPENDENT SUBQUERY t0 ALL NULL NULL NULL NULL 8 Using where
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#
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# Tests for multi-table DELETE
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#
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explain delete t1 from t0, t1 where t0.a = t1.a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
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1 SIMPLE t1 ref a a 5 test.t0.a 4
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drop table t0, t1;
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# ###################################################################
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# ## EXPLAIN UPDATE tests
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# ###################################################################
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create table t0 (a int) engine=myisam;
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insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);
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explain update t0 set a=3 where a=4;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
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create table t1 (a int, b int, filler char(100), key(a), key(b));
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insert into t1
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select A.a+10*B.a + 10*C.a, A.a+10*B.a + 10*C.a, 'filler'
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from t0 A, t0 B, t0 C;
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explain update t1 set a=a+1 where 3>4;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
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explain update t1 set a=a+1 where a=3 and a=4;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
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# This should use an index, possible_keys=NULL because there is no WHERE
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explain update t1 set a=a+1 order by a limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 512 Using filesort
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# This should use range, possible_keys={a,b}
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explain update t1 set filler='fooo' where a<20 and b < 10;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a,b a 5 NULL 1 Using where
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# This should use ALL + filesort
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explain update t1 set filler='fooo' order by a+1 limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 512 Using filesort
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# This should use range + using filesort
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explain update t1 set filler='fooo' where a<20 order by b limit 2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 range a a 5 NULL 1 Using where; Using filesort
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# Try some subqueries:
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explain update t1 set filler='fooo' where a < (select max(a) from t0);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 range a a 5 NULL 1 Using where
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2 SUBQUERY t0 ALL NULL NULL NULL NULL 8
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explain update t1 set filler='fooo' where a < (select max(a) from t0 where a < t1.b);
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t1 ALL NULL NULL NULL NULL 512 Using where
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2 DEPENDENT SUBQUERY t0 ALL NULL NULL NULL NULL 8 Using where
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#
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# Tests for multi-table UPDATE
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#
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explain update t0, t1 set t1.a=t1.a+1 where t0.a = t1.a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8 Using where
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1 SIMPLE t1 ref a a 5 test.t0.a 4
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drop table t0, t1;
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#
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# Try DELETE ... RETURNING ...
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#
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create table t0 (a int);
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insert into t0 values (1),(2),(3),(4);
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explain delete from t0 where a=1 returning a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 4 Using where
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explain delete from t0 returning a;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 4
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drop table t0;
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#
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# MDEV-5070 - EXPLAIN INSERT ... SELECT crashes on 10.0-base-explain-slowquerylog
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#
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create table t0 (a int);
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insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);
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create table t1 (a int);
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explain insert into t1 select * from t0;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8
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explain replace into t1 select * from t0;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t0 ALL NULL NULL NULL NULL 8
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drop table t0, t1;
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#
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# MDEV-5067: Valgrind warnings (Invalid read) in QPF_table_access::print_explain
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#
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CREATE TABLE t1 (i INT) ENGINE=MyISAM;
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INSERT INTO t1 VALUES (7),(0),(9);
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SELECT * FROM t1 INNER JOIN ( SELECT DISTINCT * FROM t1 ) AS sq ON (sq.i = t1.i);
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i i
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7 7
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0 0
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9 9
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DROP TABLE t1;
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#
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# MDEV-5093, MDEV-5094: EXPLAIN PARTITIONS and EXPLAIN EXTENDED do not
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# work for EXPLAIN UPDATE.
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#
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create table t1 (i int);
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explain partitions update t1 set i = 3;
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE
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create table t2 (a int, b int) partition by hash(a) partitions 5;
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insert into t2 values (0,0),(1,1),(2,2),(3,3),(4,4);
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explain partitions update t2 set b=3 where a in (3,4);
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 p3,p4 ALL NULL NULL NULL NULL 2 Using where
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explain partitions delete from t2 where a in (3,4);
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 p3,p4 ALL NULL NULL NULL NULL 2 Using where
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explain extended update t2 set b=3 where a in (3,4);
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 2 100.00 Using where
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explain extended delete from t2 where a in (3,4);
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id select_type table type possible_keys key key_len ref rows filtered Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 2 100.00 Using where
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drop table t1,t2;
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#
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# Check the special case where partition pruning removed all partitions
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#
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create table t1 (a int, b int)
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partition by range (a) (
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partition p0 values less than (10),
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partition p1 values less than (20),
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partition p2 values less than (30)
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);
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insert into t1 values (9,9), (19,19), (29,29);
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explain partitions select * from t1 where a in (32,33);
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL Impossible WHERE noticed after reading const tables
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explain partitions delete from t1 where a in (32,33);
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No matching rows after partition pruning
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explain partitions update t1 set b=12345 where a in (32,33);
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id select_type table partitions type possible_keys key key_len ref rows Extra
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1 SIMPLE NULL NULL NULL NULL NULL NULL NULL NULL No matching rows after partition pruning
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drop table t1;
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#
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# Tests for EXPLAIN INSERT ... VALUES
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#
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create table t1 (a int, key(a));
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explain insert into t1 values (1),(2),(3);
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id select_type table type possible_keys key key_len ref rows Extra
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1 INSERT t1 ALL NULL NULL NULL NULL NULL NULL
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insert into t1 values (1),(2),(3);
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create table t2 (a int, b int);
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explain insert into t2 values
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(10, 1+(select max(a) from t1)),
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(11, 1+(select max(a+1) from t1));
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id select_type table type possible_keys key key_len ref rows Extra
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1 INSERT t2 ALL NULL NULL NULL NULL NULL NULL
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3 SUBQUERY t1 index NULL a 5 NULL 3 Using index
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2 SUBQUERY NULL NULL NULL NULL NULL NULL NULL Select tables optimized away
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drop table t1,t2;
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#
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# MDEV-5122: "Commands out of sync", "Malformed packet" or client hang up on unique key violation
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#
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drop table if exists t1;
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Warnings:
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Note 1051 Unknown table 'test.t1'
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drop function if exists f1;
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create table t1 (a int, unique(a));
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create function f1(x int)
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returns int
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begin
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insert into t1 values(x),(x);
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return 10;
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end|
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select f1(100);
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ERROR 23000: Duplicate entry '100' for key 'a'
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select 'OK';
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OK
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OK
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drop function f1;
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drop table t1;
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#
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# MDEV-7038: Assertion `status_var.memory_used == 0' failed in THD::~THD()
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# on disconnect after executing EXPLAIN for multi-table UPDATE
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#
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CREATE TABLE t1 (a INT);
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CREATE VIEW v1 AS SELECT * FROM t1;
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INSERT INTO t1 VALUES (1),(2);
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EXPLAIN UPDATE v1, mysql.user SET v1.a = v1.a + 1;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t1 ALL NULL NULL NULL NULL 2
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1 SIMPLE global_priv index NULL PRIMARY 1149 NULL 5 Using index
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DROP TABLE t1;
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DROP VIEW v1;
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#
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# MDEV-8299: MyISAM or Aria table gets corrupted after EXPLAIN INSERT and INSERT
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#
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CREATE TABLE t1 (pk INT NOT NULL AUTO_INCREMENT PRIMARY KEY, i INT, KEY(i)) ENGINE=MyISAM;
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INSERT INTO t1 (i) VALUES (100),(200);
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CREATE TABLE t2 (j INT) ENGINE=MyISAM;
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INSERT INTO t2 VALUES (10),(20);
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EXPLAIN INSERT INTO t1 (i) SELECT j FROM t2;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 2
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INSERT INTO t1 (i) VALUES (300);
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CHECK TABLE t1;
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Table Op Msg_type Msg_text
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test.t1 check status OK
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DROP TABLE t1, t2;
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#
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# MDEV-8321: Assertion `! is_set()' failed in Diagnostics_area::set_eof_status on EXPLAIN INSERT ... UNION
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#
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CREATE TABLE t1 (a INT);
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CREATE TABLE t2 (b INT);
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CREATE TABLE t3 (c INT);
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INSERT INTO t1 VALUES (1),(2);
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INSERT INTO t2 VALUES (3),(4);
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INSERT INTO t3 VALUES (5),(6);
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EXPLAIN INSERT INTO t1 SELECT * FROM t2 UNION SELECT * FROM t3;
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id select_type table type possible_keys key key_len ref rows Extra
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1 PRIMARY t2 ALL NULL NULL NULL NULL 2
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2 UNION t3 ALL NULL NULL NULL NULL 2
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NULL UNION RESULT <union1,2> ALL NULL NULL NULL NULL NULL
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drop table t1,t2,t3;
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#
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# MDEV-6223: Assertion `! is_set()' fails in Diagnostics_area::set_eof_status on EXPLAIN INSERT executed as a PS
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#
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CREATE TABLE t1 (a INT) ENGINE = MyISAM;
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CREATE TABLE t2 (b INT) ENGINE = MyISAM;
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INSERT INTO t2 VALUES (1),(2);
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PREPARE stmt FROM 'EXPLAIN INSERT INTO t1 SELECT * FROM t2';
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EXECUTE stmt;
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id select_type table type possible_keys key key_len ref rows Extra
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1 SIMPLE t2 ALL NULL NULL NULL NULL 2
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drop table t1,t2;
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