executor, cmd: refine HashJoinExec for specific JoinType if outer/inner is nil

[XuHuaiyu]

What problem does this PR solve?

1. Exit HashJoinExec immediately when the inner table is nil for InnerJoin and SemiJoin.
2. Exit HashJoinExec immediately when the outer table is nil for all the join types.

What is changed and how it works?

Check List

Tests

• Integration test
• Manual test

drop table if exists t1, t2;
create table t1(a int, b int);
create table t2(a int, b int);
insert into t1 values(1,1),(2,2),(3,3),(4,4),(5,5);
select count(*) from t1;
count(*)
5
select count(*) from t2;
count(*)
0
set @@tidb_max_chunk_size=1;
explain analyze select /*+ TIDB_HJ(t1, t2) */ * from t1 where exists (select a from t2 where t1.a = t2.a);
id	count	task	operator info	execution info
HashLeftJoin_9	8000.00	root	semi join, inner:TableReader_13, equal:[eq(test.t1.a, test.t2.a)]	time:1.036712ms, loops:1, rows:0
├─TableReader_11	10000.00	root	data:TableScan_10	time:441.096µs, loops:1, rows:1
│ └─TableScan_10	10000.00	cop	table:t1, range:[-inf,+inf], keep order:false, stats:pseudo	
└─TableReader_13	10000.00	root	data:TableScan_12	time:212.376µs, loops:1, rows:0
  └─TableScan_12	10000.00	cop	table:t2, range:[-inf,+inf], keep order:false, stats:pseudo	
insert into t2 select * from t1;
delete from t1;
select count(*) from t1;
count(*)
0
select count(*) from t2;
count(*)
5
explain analyze select /*+ TIDB_HJ(t1, t2) */ * from t1 where not exists (select a from t2 where t1.a = t2.a);
id	count	task	operator info	execution info
HashLeftJoin_9	8000.00	root	anti semi join, inner:TableReader_13, equal:[eq(test.t1.a, test.t2.a)]	time:534.643µs, loops:1, rows:0
├─TableReader_11	10000.00	root	data:TableScan_10	time:35.042µs, loops:1, rows:0
│ └─TableScan_10	10000.00	cop	table:t1, range:[-inf,+inf], keep order:false, stats:pseudo	
└─TableReader_13	10000.00	root	data:TableScan_12	time:0s, loops:0, rows:0
  └─TableScan_12	10000.00	cop	table:t2, range:[-inf,+inf], keep order:false, stats:pseudo	
explain analyze select /*+ TIDB_HJ(t1, t2) */ * from t1 left outer join t2 on t1.a = t2.a;
id	count	task	operator info	execution info
HashLeftJoin_6	12500.00	root	left outer join, inner:TableReader_10, equal:[eq(test.t1.a, test.t2.a)]	time:502.553µs, loops:1, rows:0
├─TableReader_8	10000.00	root	data:TableScan_7	time:27.302µs, loops:1, rows:0
│ └─TableScan_7	10000.00	cop	table:t1, range:[-inf,+inf], keep order:false, stats:pseudo	
└─TableReader_10	10000.00	root	data:TableScan_9	time:0s, loops:0, rows:0
  └─TableScan_9	10000.00	cop	table:t2, range:[-inf,+inf], keep order:false, stats:pseudo	

Code changes

• Has exported function/method change

Side effects

Related changes

• Need to cherry-pick to the release branch
  release-2.1

[alivxxx]

LGTM

[zz-jason]

it's better to put this together with cmd/explaintest/explain-test.out

[zz-jason]

please fix ci.

[XuHuaiyu]

/run-all-tests

[zz-jason]

LGTM

[zz-jason]

/run-common-test

[zz-jason]

@XuHuaiyu This PR needs to be cherry-picked to release-2.1 branch