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Fix hash join expression matching (#1496)

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Josipmrden 2023-11-12 20:45:02 +01:00 committed by GitHub
parent 17915578f8
commit 3c413a7e50
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3 changed files with 24 additions and 2 deletions
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4
src/query/plan/operator.cpp
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@ -5404,7 +5404,7 @@ class HashJoinCursor : public Cursor {
// Check if the join value from the pulled frame is shared with any left frames
ExpressionEvaluator evaluator(&frame, context.symbol_table, context.evaluation_context, context.db_accessor,
storage::View::OLD);
auto right_value = self_.hash_join_condition_->expression1_->Accept(evaluator);
auto right_value = self_.hash_join_condition_->expression2_->Accept(evaluator);
if (hashtable_.contains(right_value)) {
// If so, finish pulling for now and proceed to joining the pulled frame
right_op_frame_.assign(frame.elems().begin(), frame.elems().end());
@ -5452,7 +5452,7 @@ class HashJoinCursor : public Cursor {
while (left_op_cursor_->Pull(frame, context)) {
ExpressionEvaluator evaluator(&frame, context.symbol_table, context.evaluation_context, context.db_accessor,
storage::View::OLD);
auto left_value = self_.hash_join_condition_->expression2_->Accept(evaluator);
auto left_value = self_.hash_join_condition_->expression1_->Accept(evaluator);
if (left_value.type() != TypedValue::Type::Null) {
hashtable_[left_value].emplace_back(frame.elems().begin(), frame.elems().end());
}

8
src/query/plan/rewrite/join.hpp
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@ -27,6 +27,7 @@
#include "query/plan/operator.hpp"
#include "query/plan/preprocess.hpp"
#include "utils/algorithm.hpp"
namespace memgraph::query::plan {
@ -523,6 +524,13 @@ class JoinRewriter final : public HierarchicalLogicalOperatorVisitor {
auto rhs_property = rhs_lookup->property_;
filter_exprs_for_removal_.insert(filter.expression);
filters_.EraseFilter(filter);
if (utils::Contains(right_symbols, lhs_symbol) && utils::Contains(left_symbols, rhs_symbol)) {
// We need to duplicate this because expressions are shared between plans
join_condition = join_condition->Clone(ast_storage_);
std::swap(join_condition->expression1_, join_condition->expression2_);
}
return std::make_unique<HashJoin>(left_op, left_symbols, right_op, right_symbols, join_condition);
}

14
tests/gql_behave/tests/memgraph_V1/features/cartesian.feature
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@ -186,6 +186,20 @@ Feature: Cartesian
| a | b |
| (:A {id: 1}) | (:B {id: 1}) |
Scenario: Multiple match with WHERE x = y 01 reversed
Given an empty graph
And having executed
"""
CREATE (:A {id: 1}), (:A {id: 2}), (:B {id: 1})
"""
When executing query:
"""
MATCH (a:A) MATCH (b:B) WHERE b.id = a.id RETURN a, b
"""
Then the result should be:
| a | b |
| (:A {id: 1}) | (:B {id: 1}) |
Scenario: Multiple match with WHERE x = y 02
Given an empty graph
And having executed