index_merge.test

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

#
# Index merge tests
#
--disable_warnings
drop table if exists t0, t1, t2, t3, t4;
--enable_warnings

# Create and fill a table with simple keys
create table t0
(
  key1 int not null, 
  INDEX i1(key1)
);

--disable_query_log
insert into t0 values (1),(2),(3),(4),(5),(6),(7),(8);

let $1=7;
set @d=8;
while ($1)
{
  eval insert into t0 select key1+@d from t0;
  eval set @d=@d*2;
  dec $1;
}
--enable_query_log

alter table t0 add key2 int not null, add index i2(key2);
alter table t0 add key3 int not null, add index i3(key3);
alter table t0 add key4 int not null, add index i4(key4);
alter table t0 add key5 int not null, add index i5(key5);
alter table t0 add key6 int not null, add index i6(key6);
alter table t0 add key7 int not null, add index i7(key7);
alter table t0 add key8 int not null, add index i8(key8);

update t0 set key2=key1,key3=key1,key4=key1,key5=key1,key6=key1,key7=key1,key8=1024-key1;
analyze table t0;

# 1. One index 
explain select * from t0 where key1 < 3 or key1 > 1020;

# 2. Simple cases
explain 
select * from t0 where key1 < 3 or key2 > 1020;
select * from t0 where key1 < 3 or key2 > 1020;

explain select * from t0 where key1 < 3 or key2 <4;

explain
select * from t0 where (key1 > 30 and key1<35) or (key2 >32 and key2 < 40);
select * from t0 where (key1 > 30 and key1<35) or (key2 >32 and key2 < 40);

# 3. Check that index_merge doesn't break "ignore/force/use index"
explain select * from t0 ignore index (i2) where key1 < 3 or key2 <4;
explain select * from t0 where (key1 < 3 or key2 <4) and key3 = 50;
explain select * from t0 use index (i1,i2) where (key1 < 3 or key2 <4) and key3 = 50;

explain select * from t0 where (key1 > 1 or key2  > 2);
explain select * from t0 force index (i1,i2) where (key1 > 1 or key2  > 2);


# 4. Check if conjuncts are grouped by keyuse
explain 
  select * from t0 where key1<3 or key2<3 or (key1>5 and key1<8) or 
  (key1>10 and key1<12) or (key2>100 and key2<110);

# 5. Check index_merge with conjuncts that are always true/false
#    verify fallback to "range" if there is only one non-confluent condition
explain select * from t0 where key2 = 45 or key1 <=> null;

explain select * from t0 where key2 = 45 or key1 is not null;
explain select * from t0 where key2 = 45 or key1 is null;

#   the last conj. is always false and will be discarded
explain select * from t0 where key2=10 or key3=3 or key4 <=> null;

#   the last conj. is always true and will cause 'all' scan
explain select * from t0 where key2=10 or key3=3 or key4 is null;

#   some more complicated cases
explain select key1 from t0 where (key1 <=> null) or (key2 < 5) or 
                                   (key3=10) or (key4 <=> null);
explain select key1 from t0 where (key1 <=> null) or (key1 < 5) or 
                                   (key3=10) or (key4 <=> null);

# 6.Several ways to do index_merge, (ignored) index_merge vs. range
explain select * from t0 where 
  (key1 < 3 or key2 < 3) and (key3 < 4 or key4 < 4) and (key5 < 5 or key6 < 5);

explain
select * from t0 where (key1 < 3 or key2 < 6) and (key1 < 7 or key3 < 4);

select * from t0 where (key1 < 3 or key2 < 6) and (key1 < 7 or key3 < 4);


explain select * from t0 where 
  (key1 < 3 or key2 < 3) and (key3 < 4 or key4 < 4) and (key5 < 2 or key6 < 2);
                                                                  
#   now index_merge is not used at all when "range" is possible
explain select * from t0 where 
  (key1 < 3 or key2 < 3) and (key3 < 100);

#   this even can cause "all" scan:
explain select * from t0 where
  (key1 < 3 or key2 < 3) and (key3 < 1000);
  

# 7. Complex cases
#   tree_or(List<SEL_IMERGE>, range SEL_TREE).
explain select * from t0 where 
    ((key1 < 4 or key2 < 4) and (key2 <5 or key3 < 4)) 
  or 
    key2 > 5;

explain select * from t0 where
    ((key1 < 4 or key2 < 4) and (key2 <5 or key3 < 4))
  or
    key1 < 7;

select * from t0 where
    ((key1 < 4 or key2 < 4) and (key2 <5 or key3 < 4))
  or
    key1 < 7;
        
#   tree_or(List<SEL_IMERGE>, List<SEL_IMERGE>).   
explain select * from t0 where 
    ((key1 < 4 or key2 < 4) and (key3 <5 or key5 < 4)) 
  or 
    ((key5 < 5 or key6 < 6) and (key7 <7 or key8 < 4));

explain select * from t0 where
    ((key3 <5 or key5 < 4) and (key1 < 4 or key2 < 4))
  or
    ((key7 <7 or key8 < 4) and (key5 < 5 or key6 < 6));
    
explain select * from t0 where
    ((key3 <5 or key5 < 4) and (key1 < 4 or key2 < 4))
  or
    ((key3 <7 or key5 < 2) and (key5 < 5 or key6 < 6));

explain select * from t0 where
    ((key3 <5 or key5 < 4) and (key1 < 4 or key2 < 4))
  or
    (((key3 <7 and key7 < 6) or key5 < 2) and (key5 < 5 or key6 < 6));

explain select * from t0 where
    ((key3 <5 or key5 < 4) and (key1 < 4 or key2 < 4))
  or
    ((key3 >=5 or key5 < 2) and (key5 < 5 or key6 < 6));

explain select * from t0 force index(i1, i2, i3, i4, i5, i6 ) where
    ((key3 <5 or key5 < 4) and (key1 < 4 or key2 < 4))
  or
    ((key3 >=5 or key5 < 2) and (key5 < 5 or key6 < 6));
    
# 8. Verify that "order by" after index merge uses filesort
select * from t0 where key1 < 5 or key8 < 4 order by key1;

explain
select * from t0 where key1 < 5 or key8 < 4 order by key1;

# 9. Check that index_merge cost is compared to 'index' where possible
create table t2 like t0;
insert into t2 select * from t0;

alter table t2 add index i1_3(key1, key3);
alter table t2 add index i2_3(key2, key3);
alter table t2 drop index i1;
alter table t2 drop index i2;
alter table t2 add index i321(key3, key2, key1);

#   index_merge vs 'index', index_merge is better.
explain select key3 from t2 where key1 = 100 or key2 = 100;

#   index_merge vs 'index', 'index' is better.
explain select key3 from t2 where key1 <100 or key2 < 100;

#   index_merge vs 'all', index_merge is better.
explain select key7 from t2 where key1 <100 or key2 < 100;

# 10. Multipart keys.
create table t4 (
  key1a int not null,
  key1b int not null,
  key2  int not null,
  key2_1 int not null,
  key2_2 int not null,
  key3  int not null,
  
  index i1a (key1a, key1b),
  index i1b (key1b, key1a),
  
  index i2_1(key2, key2_1),
  index i2_2(key2, key2_1)
);

insert into t4 select key1,key1,key1 div 10, key1 % 10, key1 % 10, key1 from t0;

#   the following will be handled by index_merge:
select * from t4 where key1a = 3 or key1b = 4; 
explain select * from t4 where key1a = 3 or key1b = 4; 

#   and the following will not
explain select * from t4 where key2 = 1 and (key2_1 = 1 or key3 = 5);

explain select * from t4 where key2 = 1 and (key2_1 = 1 or key2_2 = 5);

explain select * from t4 where key2_1 = 1 or key2_2 = 5;


# 11. Multitable selects
create table t1 like t0;
insert into t1 select * from t0;

#  index_merge on first table in join
explain select * from t0 left join t1 on (t0.key1=t1.key1) 
  where t0.key1=3 or t0.key2=4; 

select * from t0 left join t1 on (t0.key1=t1.key1)
  where t0.key1=3 or t0.key2=4;

explain 
select * from t0,t1 where (t0.key1=t1.key1) and ( t0.key1=3 or t0.key2=4);

#  index_merge vs. ref
explain 
select * from t0,t1 where (t0.key1=t1.key1) and 
  (t0.key1=3 or t0.key2=4) and t1.key1<200;

#  index_merge vs. ref
explain 
select * from t0,t1 where (t0.key1=t1.key1) and 
  (t0.key1=3 or t0.key2<4) and t1.key1=2;