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feat(optimizer): Implement LIKE expression rule for query optimization #96

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feat(optimizer): Implement LIKE expression rule for query optimization #96

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0e95ab4
feat(optimizer): Implement LIKE operator rule for query optimization
loloxwg Nov 12, 2023
e999789
fmt
loloxwg Nov 12, 2023
5ce7a82
fix(rbo): Rewrite code logic
loloxwg Dec 5, 2023
696232c
fix(rbo): COMMIT
loloxwg Dec 5, 2023
5b1d4ed
fix(rbo): finish
loloxwg Dec 5, 2023
74e622c
cargo fmt
loloxwg Dec 5, 2023
082b635
Test: Add some e2e test and unit test
loloxwg Dec 23, 2023
c699ce3
Fmt: cargo fmt
loloxwg Dec 23, 2023
b3c9992
Merge remote-tracking branch 'upstream/main' into like
loloxwg Dec 23, 2023
143f128
Fix: merge issue
loloxwg Dec 23, 2023
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20 changes: 17 additions & 3 deletions src/db.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -74,10 +74,10 @@ impl<S: Storage> Database<S> {
/// Limit(1)
/// Project(a,b)
let source_plan = binder.bind(&stmts[0])?;
// println!("source_plan plan: {:#?}", source_plan);
//println!("source_plan plan: {:#?}", source_plan);

let best_plan = Self::default_optimizer(source_plan).find_best()?;
// println!("best_plan plan: {:#?}", best_plan);
//println!("best_plan plan: {:#?}", best_plan);

Ok(build(best_plan, &transaction))
}
Expand All @@ -92,7 +92,11 @@ impl<S: Storage> Database<S> {
.batch(
"Simplify Filter".to_string(),
HepBatchStrategy::fix_point_topdown(10),
vec![RuleImpl::SimplifyFilter, RuleImpl::ConstantCalculation],
vec![
RuleImpl::LikeRewrite,
RuleImpl::SimplifyFilter,
RuleImpl::ConstantCalculation,
],
)
.batch(
"Predicate Pushdown".to_string(),
Expand Down Expand Up @@ -305,6 +309,12 @@ mod test {
let _ = kipsql
.run("insert into t3 (a, b) values (4, 4444), (5, 5222), (6, 1.00)")
.await?;
let _ = kipsql
.run("create table t4 (a int primary key, b varchar(100))")
.await?;
let _ = kipsql
.run("insert into t4 (a, b) values (1, 'abc'), (2, 'abdc'), (3, 'abcd'), (4, 'ddabc')")
.await?;

println!("show tables:");
let tuples_show_tables = kipsql.run("show tables").await?;
Expand Down Expand Up @@ -470,6 +480,10 @@ mod test {
let tuples_decimal = kipsql.run("select * from t3").await?;
println!("{}", create_table(&tuples_decimal));

println!("like rewrite:");
let tuples_like_rewrite = kipsql.run("select * from t4 where b like 'abc%'").await?;
println!("{}", create_table(&tuples_like_rewrite));

Ok(())
}
}
5 changes: 4 additions & 1 deletion src/optimizer/rule/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,8 +9,8 @@ use crate::optimizer::rule::pushdown_limit::{
};
use crate::optimizer::rule::pushdown_predicates::PushPredicateIntoScan;
use crate::optimizer::rule::pushdown_predicates::PushPredicateThroughJoin;
use crate::optimizer::rule::simplification::ConstantCalculation;
use crate::optimizer::rule::simplification::SimplifyFilter;
use crate::optimizer::rule::simplification::{ConstantCalculation, LikeRewrite};
use crate::optimizer::OptimizerError;

mod column_pruning;
Expand All @@ -37,6 +37,7 @@ pub enum RuleImpl {
// Simplification
SimplifyFilter,
ConstantCalculation,
LikeRewrite,
}

impl Rule for RuleImpl {
Expand All @@ -53,6 +54,7 @@ impl Rule for RuleImpl {
RuleImpl::PushPredicateIntoScan => PushPredicateIntoScan.pattern(),
RuleImpl::SimplifyFilter => SimplifyFilter.pattern(),
RuleImpl::ConstantCalculation => ConstantCalculation.pattern(),
RuleImpl::LikeRewrite => LikeRewrite.pattern(),
}
}

Expand All @@ -69,6 +71,7 @@ impl Rule for RuleImpl {
RuleImpl::SimplifyFilter => SimplifyFilter.apply(node_id, graph),
RuleImpl::PushPredicateIntoScan => PushPredicateIntoScan.apply(node_id, graph),
RuleImpl::ConstantCalculation => ConstantCalculation.apply(node_id, graph),
RuleImpl::LikeRewrite => LikeRewrite.apply(node_id, graph),
}
}
}
Expand Down
208 changes: 200 additions & 8 deletions src/optimizer/rule/simplification.rs
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Original file line number Diff line number Diff line change
@@ -1,11 +1,21 @@
use crate::expression::{BinaryOperator, ScalarExpression};
use crate::optimizer::core::pattern::{Pattern, PatternChildrenPredicate};
use crate::optimizer::core::rule::Rule;
use crate::optimizer::heuristic::graph::{HepGraph, HepNodeId};
use crate::optimizer::OptimizerError;
use crate::planner::operator::filter::FilterOperator;
use crate::planner::operator::join::JoinCondition;
use crate::planner::operator::Operator;
use crate::types::value::{DataValue, ValueRef};
use crate::types::LogicalType;
use lazy_static::lazy_static;
lazy_static! {
static ref LIKE_REWRITE_RULE: Pattern = {
Pattern {
predicate: |op| matches!(op, Operator::Filter(_)),
children: PatternChildrenPredicate::None,
}
};
static ref CONSTANT_CALCULATION_RULE: Pattern = {
Pattern {
predicate: |_| true,
Expand Down Expand Up @@ -109,6 +119,99 @@ impl Rule for SimplifyFilter {
}
}

pub struct LikeRewrite;

impl Rule for LikeRewrite {
fn pattern(&self) -> &Pattern {
&LIKE_REWRITE_RULE
}

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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@KKould KKould Dec 25, 2023 •
edited
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Use the operator_mut method to modify directly instead of replace

if let ScalarExpression::Binary {
op: BinaryOperator::Like,
ref mut left_expr,
ref mut right_expr,
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

if let DataValue::Utf8(value_str) = (**value).clone() {
Self::process_value_str(value_str, left_expr, ty, &mut filter_op);
}
}
}
graph.replace_node(node_id, Operator::Filter(filter_op))
}
Ok(())
}
}

impl LikeRewrite {
fn process_value_str(
value_str: Option<String>,
left_expr: &mut Box<ScalarExpression>,
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

if value_str.ends_with('%') {
let left_bound = value_str.trim_end_matches('%');
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@KKould KKould Dec 25, 2023 •
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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,
     );
}

let right_bound = increment_last_char(left_bound);
right_bound.map(|rb| {
filter_op.predicate = Self::create_new_expr(
&mut left_expr.clone(),
ty,
left_bound.to_string(),
rb,
);
});
}
});
}

fn create_new_expr(
left_expr: &mut Box<ScalarExpression>,
ty: LogicalType,
left_bound: String,
right_bound: String,
) -> ScalarExpression {
let new_expr = ScalarExpression::Binary {
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Meaningless variable declaration -> new_expr

op: BinaryOperator::And,
left_expr: Box::new(ScalarExpression::Binary {
op: BinaryOperator::GtEq,
left_expr: left_expr.clone(),
right_expr: Box::new(ScalarExpression::Constant(ValueRef::from(DataValue::Utf8(
Some(left_bound),
)))),
ty,
}),

right_expr: Box::new(ScalarExpression::Binary {
op: BinaryOperator::Lt,
left_expr: left_expr.clone(),
right_expr: Box::new(ScalarExpression::Constant(ValueRef::from(DataValue::Utf8(
Some(right_bound),
)))),
ty,
}),
ty,
};
new_expr
}
}

fn increment_last_char(s: &str) -> Option<String> {
let mut chars: Vec<char> = s.chars().collect();
for i in (0..chars.len()).rev() {
if let Some(next_char) = std::char::from_u32(chars[i] as u32 + 1) {
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chars[i] = next_char;
return Some(chars.into_iter().collect());
}
}
None
}

#[cfg(test)]
mod test {
use crate::binder::test::select_sql_run;
Expand All @@ -118,6 +221,7 @@ mod test {
use crate::expression::{BinaryOperator, ScalarExpression, UnaryOperator};
use crate::optimizer::heuristic::batch::HepBatchStrategy;
use crate::optimizer::heuristic::optimizer::HepOptimizer;
use crate::optimizer::rule::simplification::increment_last_char;
use crate::optimizer::rule::RuleImpl;
use crate::planner::operator::filter::FilterOperator;
use crate::planner::operator::Operator;
Expand All @@ -127,6 +231,13 @@ mod test {
use std::collections::Bound;
use std::sync::Arc;

#[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

assert_eq!(increment_last_char("abz"), Some("ab{".to_string()));
assert_eq!(increment_last_char("ab}"), Some("ab~".to_string()));
}

#[tokio::test]
async fn test_constant_calculation_omitted() -> Result<(), DatabaseError> {
// (2 + (-1)) < -(c1 + 1)
Expand Down Expand Up @@ -343,7 +454,7 @@ mod test {
cb_1_c1,
Some(ConstantBinary::Scope {
min: Bound::Unbounded,
max: Bound::Excluded(Arc::new(DataValue::Int32(Some(-2))))
max: Bound::Excluded(Arc::new(DataValue::Int32(Some(-2)))),
})
);

Expand All @@ -353,7 +464,7 @@ mod test {
cb_1_c2,
Some(ConstantBinary::Scope {
min: Bound::Excluded(Arc::new(DataValue::Int32(Some(2)))),
max: Bound::Unbounded
max: Bound::Unbounded,
})
);

Expand All @@ -363,7 +474,7 @@ mod test {
cb_2_c1,
Some(ConstantBinary::Scope {
min: Bound::Excluded(Arc::new(DataValue::Int32(Some(2)))),
max: Bound::Unbounded
max: Bound::Unbounded,
})
);

Expand All @@ -373,7 +484,7 @@ mod test {
cb_1_c1,
Some(ConstantBinary::Scope {
min: Bound::Unbounded,
max: Bound::Excluded(Arc::new(DataValue::Int32(Some(-2))))
max: Bound::Excluded(Arc::new(DataValue::Int32(Some(-2)))),
})
);

Expand All @@ -383,7 +494,7 @@ mod test {
cb_3_c1,
Some(ConstantBinary::Scope {
min: Bound::Unbounded,
max: Bound::Excluded(Arc::new(DataValue::Int32(Some(-1))))
max: Bound::Excluded(Arc::new(DataValue::Int32(Some(-1)))),
})
);

Expand All @@ -393,7 +504,7 @@ mod test {
cb_3_c2,
Some(ConstantBinary::Scope {
min: Bound::Excluded(Arc::new(DataValue::Int32(Some(0)))),
max: Bound::Unbounded
max: Bound::Unbounded,
})
);

Expand All @@ -403,7 +514,7 @@ mod test {
cb_4_c1,
Some(ConstantBinary::Scope {
min: Bound::Excluded(Arc::new(DataValue::Int32(Some(0)))),
max: Bound::Unbounded
max: Bound::Unbounded,
})
);

Expand All @@ -413,7 +524,7 @@ mod test {
cb_4_c2,
Some(ConstantBinary::Scope {
min: Bound::Unbounded,
max: Bound::Excluded(Arc::new(DataValue::Int32(Some(-1))))
max: Bound::Excluded(Arc::new(DataValue::Int32(Some(-1)))),
})
);

Expand Down Expand Up @@ -450,4 +561,85 @@ mod test {

Ok(())
}

#[tokio::test]
async fn test_like_rewrite() -> Result<(), DatabaseError> {
let plan = select_sql_run("select * from t1 where c1 like 'abc%%'").await?;
let best_plan = HepOptimizer::new(plan.clone())
.batch(
"test_like_rewrite".to_string(),
HepBatchStrategy::once_topdown(),
vec![RuleImpl::LikeRewrite],
)
.find_best()?;
assert_eq!(best_plan.childrens.len(), 1);

match best_plan.operator {
Operator::Project(op) => {
assert_eq!(op.exprs.len(), 2);
}
_ => unreachable!(),
}

match &best_plan.childrens[0].operator {
Operator::Filter(op) => {
assert_eq!(
op.predicate,
ScalarExpression::Binary {
op: BinaryOperator::And,
left_expr: Box::new(ScalarExpression::Binary {
op: BinaryOperator::GtEq,
left_expr: Box::new(ScalarExpression::ColumnRef(Arc::new(
ColumnCatalog {
summary: ColumnSummary {
id: Some(0),
name: "c1".to_string(),
},
nullable: false,
desc: ColumnDesc {
column_datatype: LogicalType::Integer,
is_primary: true,
is_unique: false,
default: None,
},
ref_expr: None,
}
))),
right_expr: Box::new(ScalarExpression::Constant(Arc::new(
DataValue::Utf8(Some("abc".to_string()))
))),
ty: LogicalType::Boolean,
}),
right_expr: Box::new(ScalarExpression::Binary {
op: BinaryOperator::Lt,
left_expr: Box::new(ScalarExpression::ColumnRef(Arc::new(
ColumnCatalog {
summary: ColumnSummary {
id: Some(0),
name: "c1".to_string(),
},
nullable: false,
desc: ColumnDesc {
column_datatype: LogicalType::Integer,
is_primary: true,
is_unique: false,
default: None,
},
ref_expr: None,
}
))),
right_expr: Box::new(ScalarExpression::Constant(Arc::new(
DataValue::Utf8(Some("abd".to_string()))
))),
ty: LogicalType::Boolean,
}),
ty: LogicalType::Boolean,
}
);
}
_ => unreachable!(),
}

Ok(())
}
}
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