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Reduce the application of simplification #2204

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merged 3 commits into from Mar 4, 2020
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Reduce the application of simplification #2204

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b5e96e5
reduce the application of simplification
frankmcsherry Mar 4, 2020
96a9587
use hashset equality
frankmcsherry Mar 4, 2020
9128ad5
correct doctest
frankmcsherry Mar 4, 2020
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230 changes: 125 additions & 105 deletions src/expr/transform/simplify.rs
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Expand Up @@ -42,7 +42,7 @@
//! let complex_equality = ScalarExpr::Column(0).call_binary(ScalarExpr::Column(0), BinaryFunc::Eq);
//! let mut relation = RelationExpr::filter(
//! join,
//! vec![ScalarExpr::Column(1).call_binary(complex_equality.clone(), BinaryFunc::Eq)]
//! vec![ScalarExpr::Column(2).call_binary(complex_equality.clone(), BinaryFunc::Eq)]
//! );
//!
//! SimplifyFilterPredicates.transform(&mut relation);
Expand All @@ -54,7 +54,7 @@
//! // pointing to the newly Map-ped column
//! // 2) The whole RelationExpr to be wrapped in a Project to remove the newly Map-ped column
//! let expected_join = RelationExpr::join(vec![input0.map(vec![complex_equality]), input1], vec![vec![]]);
//! let updated_equality = ScalarExpr::Column(1).call_binary(ScalarExpr::Column(2), BinaryFunc::Eq);
//! let updated_equality = ScalarExpr::Column(3).call_binary(ScalarExpr::Column(2), BinaryFunc::Eq);
//! let expected_relation = expected_join.filter(vec![updated_equality]).project(vec![0, 1, 3, 4]);
//!
//! assert_eq!(relation, expected_relation);
Expand Down Expand Up @@ -125,120 +125,140 @@ impl SimplifyFilterPredicates {
expr2,
} = &predicates[i]
{
match (
supports_complex_equality_on_input(&*expr1, &input_relation),
supports_complex_equality_on_input(&*expr2, &input_relation),
) {
(Some(input_index_1), Some(input_index_2)) => {
// Predicates like `expr1 = expr2` where expr1, expr2 are both complex
// equalities and on the same input will already have been simplified.
// Will only get here if they are on different inputs.
let map_1 = create_map_over_input(
inputs[input_index_1].take_dangerous(),
expr1,
prior_arities[input_index_1],
);
let map_1_arity = map_1.arity();
inputs[input_index_1] = map_1;
// We are interested only when each expression depends on exactly one
// relation, and the two relations are different.
let mut support1 = std::collections::HashSet::new();
expr1.visit(&mut |e| {
if let ScalarExpr::Column(i) = e {
support1.insert(input_relation[*i]);
}
});
let mut support2 = std::collections::HashSet::new();
expr2.visit(&mut |e| {
if let ScalarExpr::Column(i) = e {
support2.insert(input_relation[*i]);
}
});
if support1.len() == 1 && support2.len() == 1 && support1 != support2 {
match (
supports_complex_equality_on_input(&*expr1, &input_relation),
supports_complex_equality_on_input(&*expr2, &input_relation),
) {
(Some(input_index_1), Some(input_index_2)) => {
// Predicates like `expr1 = expr2` where expr1, expr2 are both complex
// equalities and on the same input will already have been simplified.
// Will only get here if they are on different inputs.
let map_1 = create_map_over_input(
inputs[input_index_1].take_dangerous(),
expr1,
prior_arities[input_index_1],
);
let map_1_arity = map_1.arity();
inputs[input_index_1] = map_1;

let mut new_column_input_1_index =
prior_arities[input_index_1] + map_1_arity - 1;
let mut new_column_input_1_index =
prior_arities[input_index_1] + map_1_arity - 1;

let map_2 = create_map_over_input(
inputs[input_index_2].take_dangerous(),
expr2,
prior_arities[input_index_2],
);
let map_2_arity = map_2.arity();
inputs[input_index_2] = map_2;
let map_2 = create_map_over_input(
inputs[input_index_2].take_dangerous(),
expr2,
prior_arities[input_index_2],
);
let map_2_arity = map_2.arity();
inputs[input_index_2] = map_2;

let mut new_column_input_2_index =
prior_arities[input_index_2] + map_2_arity - 1;
if new_column_input_1_index <= new_column_input_2_index {
new_column_input_2_index += 1;
} else {
new_column_input_1_index += 1;
}
columns_to_drop.push(new_column_input_1_index);
columns_to_drop.push(new_column_input_2_index);
let mut new_column_input_2_index =
prior_arities[input_index_2] + map_2_arity - 1;
if new_column_input_1_index <= new_column_input_2_index {
new_column_input_2_index += 1;
} else {
new_column_input_1_index += 1;
}
columns_to_drop.push(new_column_input_1_index);
columns_to_drop.push(new_column_input_2_index);

Some((
ScalarExpr::CallBinary {
func: BinaryFunc::Eq,
expr1: Box::from(ScalarExpr::Column(
new_column_input_1_index,
)),
expr2: Box::from(ScalarExpr::Column(
new_column_input_2_index,
)),
},
i,
vec![new_column_input_1_index, new_column_input_2_index],
))
}
(Some(input_index_1), None) => {
let map = create_map_over_input(
inputs[input_index_1].take_dangerous(),
expr1,
prior_arities[input_index_1],
);
let map_arity = map.arity();
inputs[input_index_1] = map;
Some((
ScalarExpr::CallBinary {
func: BinaryFunc::Eq,
expr1: Box::from(ScalarExpr::Column(
new_column_input_1_index,
)),
expr2: Box::from(ScalarExpr::Column(
new_column_input_2_index,
)),
},
i,
vec![new_column_input_1_index, new_column_input_2_index],
))
}
(Some(input_index_1), None) => {
let map = create_map_over_input(
inputs[input_index_1].take_dangerous(),
expr1,
prior_arities[input_index_1],
);
let map_arity = map.arity();
inputs[input_index_1] = map;

let new_column_index = prior_arities[input_index_1] + map_arity - 1;
columns_to_drop.push(new_column_index);
let new_column_index =
prior_arities[input_index_1] + map_arity - 1;
columns_to_drop.push(new_column_index);

Some((
ScalarExpr::CallBinary {
func: BinaryFunc::Eq,
expr1: Box::from(ScalarExpr::Column(new_column_index)),
expr2: Box::from(match **expr2 {
ScalarExpr::Column(index) => {
if index >= new_column_index {
ScalarExpr::Column(index + 1)
} else {
ScalarExpr::Column(index)
Some((
ScalarExpr::CallBinary {
func: BinaryFunc::Eq,
expr1: Box::from(ScalarExpr::Column(new_column_index)),
expr2: Box::from(match **expr2 {
ScalarExpr::Column(index) => {
if index >= new_column_index {
ScalarExpr::Column(index + 1)
} else {
ScalarExpr::Column(index)
}
}
}
_ => *expr2.clone(),
}),
},
i,
vec![new_column_index],
))
}
(None, Some(input_index_2)) => {
let map = create_map_over_input(
inputs[input_index_2].take_dangerous(),
expr2,
prior_arities[input_index_2],
);
let map_arity = map.arity();
inputs[input_index_2] = map;
_ => *expr2.clone(),
}),
},
i,
vec![new_column_index],
))
}
(None, Some(input_index_2)) => {
let map = create_map_over_input(
inputs[input_index_2].take_dangerous(),
expr2,
prior_arities[input_index_2],
);
let map_arity = map.arity();
inputs[input_index_2] = map;

let new_column_index = prior_arities[input_index_2] + map_arity - 1;
columns_to_drop.push(new_column_index);
let new_column_index =
prior_arities[input_index_2] + map_arity - 1;
columns_to_drop.push(new_column_index);

Some((
ScalarExpr::CallBinary {
func: BinaryFunc::Eq,
expr1: Box::from(match **expr1 {
ScalarExpr::Column(index) => {
if index >= new_column_index {
ScalarExpr::Column(index + 1)
} else {
ScalarExpr::Column(index)
Some((
ScalarExpr::CallBinary {
func: BinaryFunc::Eq,
expr1: Box::from(match **expr1 {
ScalarExpr::Column(index) => {
if index >= new_column_index {
ScalarExpr::Column(index + 1)
} else {
ScalarExpr::Column(index)
}
}
}
_ => *expr1.clone(),
}), // this column needs to be updated.
expr2: Box::from(ScalarExpr::Column(new_column_index)),
},
i,
vec![new_column_index],
))
_ => *expr1.clone(),
}), // this column needs to be updated.
expr2: Box::from(ScalarExpr::Column(new_column_index)),
},
i,
vec![new_column_index],
))
}
(None, None) => None,
}
(None, None) => None,
} else {
None
}
} else {
None
Expand Down