Extend expression pushdown support

[assaf2]

At ConnectorExpressionTranslator, support conversion of expressions such Cast, NotExpression, IsNullPredicate, IsNotNullPredicate, ArithmeticBinaryExpression. These expressions can be represented as function calls rather than new types of ConnectorExpression.

EDIT: GenericLiteral, LogicalExpression, ComparisonExpression and Cast were implemented at #11086.

[slhmy]

@assaf2 I'm trying to implement visitArithmeticBinary for ArithmeticBinaryExpression.
Then I found when the left and right expression of ArithmeticBinaryExpression are in different type, they are CastExpression wrapped outside them.

CAST(DECIMAL '1.0' AS decimal(2, 1))

So I think CastExpression also needed conversion.

[slhmy]

Also, does this issue means we need to implement Functions like AND, OR and so on?
I tried to pushdown these expression down as Call, then I found they can not be handled like $like_pattern.

I found ArithmeticBinaryExpression and ComparisonExpression will not have the above problem, they have implemented ScalarOperators.
But LogicalExpression is different, it has an unsure params count, and don't have ScalarOperator/Function to handle them.

My solution is making a nested call for LogicalExpression which make every logical call have two parameters, then implementing a function for AND and OR.
Obviously it's not a good solution..

[assaf2]

@slhmy Thanks for sharing this, I'll check it when I'll start working on this issue, immediately after #7994 is merged.

[findepi]

NotExpression, IsNullPredicate, IsNotNullPredicate, ArithmeticBinaryExpression. These expressions can be represented as function calls rather than new types of ConnectorExpression.

i think the biggest cost related to adding support for these is to define how they should be modeled, and the rest is just executing on the plan

I propose

• NotExpression -> Call("$not")
• IsNullPredicate -> Call("$is_null")
• IsNotNullPredicate -> Call("$not", Call("$is_null"))
• ArithmeticBinaryExpression -> Call with $plus, $minus, $multiply, $divide function names

(The reason for using $ in all names is to avoid collisions with existing, or potentially existing, functions with similar names.)

@martint please comment or upvote this.

cc @hashhar @wendigo @losipiuk

[findepi]

ArithmeticBinaryExpression -> Call with $plus, $minus, $multiply, $divide function names

#11511

• NotExpression -> Call("$not")
• IsNullPredicate -> Call("$is_null")
• IsNotNullPredicate -> Call("$not", Call("$is_null"))

#11514

[assaf2]

CAST: #11551
BETWEEN translation: #11684 (already pushed down as $and(val >= min, val <= max))
COALESCE #11535

[assaf2]

IF and CASE #11699