This directory is the new SQL layer, including the new analyzer and cascades like optimizer and exec plan builder

|-- README
|-- analyzer
|== optimizer
|   |-- cost
|   |-- operator
|   |   |-- logical
|   |   |-- pattern
|   |   |-- physical
|   |   |-- scalar
|   |-- rule
|   |-- statistics
|-- plan (exec plan fragment build)
|-- tree (basic classes for tree structure traversal)

## Plan

### HashJoinNode
#### eqJoinConjuncts
Equal conjuncts in Join On
For SQL
```
select * from t1 join t2 on t1.id = t2.id and t1.id2 = t2.id2;
```
`t1.id = t2.id` and `t1.id2 = t2.id2` is eqJoinConjuncts
#### otherJoinConjuncts
Conjuncts in Join On and is not eqJoinConjuncts
For SQL
```
select * from t1 join t2 on t1.id = t2.id and t1.id2 > 3;
```
`t1.id2 > 3` is otherJoinConjuncts
#### conjuncts
Join followed by a filter predicate, usually in Where and Having
For SQL
```
select * from t1 join t2 on t1.id = t2.id where t1.id2 > 3;
```
`t1.id2 > 3` is conjuncts