feat(optimizer): Implement LIKE expression rule for query optimization #96
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The commit introduces a new rule for the optimization of LIKE operator in SQL queries. The LIKE operator expressions are rewritten to make use of binary operators such as GtEq and Lt in certain cases which enhances the performance of queries. Additionally, new tests for incremented character rule have been added, and `LikeRewrite` has been added to optimizer rules in the rule set.
loloxwg
changed the title
KKould
reviewed
Nov 12, 2023
KKould
reviewed
Nov 12, 2023
KKould
reviewed
Nov 12, 2023
KKould
reviewed
Nov 12, 2023
src/optimizer/rule/simplification.rs
Outdated
| { | ||
| // if left is column and right is constant | ||
| if let ScalarExpression::ColumnRef(_) = left_expr.as_ref() { | ||
| if let ScalarExpression::Constant(value) = right_expr.as_ref() { |
There was a problem hiding this comment.
reduce unnecessary nesting and matching
if let ScalarExpression::Constant(DataValue::Utf8(mut val)) = right_expr.as_ref() {
KKould
reviewed
Nov 12, 2023
|
It looks good, but it lacks the test of the rules. Reference: https://github.com/KipData/KipSQL/blob/main/src/optimizer/rule/column_pruning.rs#L166 |
KKould
reviewed
Dec 25, 2023
| } | ||
|
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||
| fn apply(&self, node_id: HepNodeId, graph: &mut HepGraph) -> Result<(), OptimizerError> { | ||
| if let Operator::Filter(mut filter_op) = graph.operator(node_id).clone() { |
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Use the operator_mut method to modify directly instead of replace
KKould
reviewed
Dec 25, 2023
| ty, | ||
| } = filter_op.predicate.clone() | ||
| { | ||
| if let ScalarExpression::Constant(value) = right_expr.as_ref() { |
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if let ScalarExpression::Constant(DataValue::Utf8(Some(value))) = right_expr.as_mut()
Instead of pattern matching layer by layer again
KKould
reviewed
Dec 25, 2023
| ty: LogicalType, | ||
| filter_op: &mut FilterOperator, | ||
| ) { | ||
| value_str.map(|value_str| { |
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Method encapsulation of little significance, just to collapse the nesting
KKould
reviewed
Dec 25, 2023
| ) { | ||
| value_str.map(|value_str| { | ||
| if value_str.ends_with('%') { | ||
| let left_bound = value_str.trim_end_matches('%'); |
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if let Some(right_bound) = increment_last_char(left_bound) {
filter_op.predicate = Self::create_new_expr(
&mut left_expr.clone(),
ty,
left_bound.to_string(),
right_bound,
);
}
KKould
reviewed
Dec 25, 2023
| left_bound: String, | ||
| right_bound: String, | ||
| ) -> ScalarExpression { | ||
| let new_expr = ScalarExpression::Binary { |
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Meaningless variable declaration -> new_expr
KKould
reviewed
Dec 25, 2023
| @@ -127,6 +231,13 @@ mod test { | |||
| use std::collections::Bound; | |||
| use std::sync::Arc; | |||
|
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| #[test] | |||
| fn test_increment_char() { | |||
| assert_eq!(increment_last_char("abc"), Some("abd".to_string())); | |||
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There are too few test cases and there is no test carry situation
KKould
reviewed
Dec 25, 2023
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The commit introduces a new rule for the optimization of LIKE operator in SQL queries. The LIKE operator expressions are rewritten to make use of binary operators such as GtEq and Lt in certain cases which enhances the performance of queries. Additionally, new tests for incremented character rule have been added, and
LikeRewritehas been added to optimizer rules in the rule set.What problem does this PR solve?
Add corresponding issue link with summary if exists -->
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What is changed and how it works?
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