From d706a91b1bacbad8d6cdd1916ff354670e2c9aec Mon Sep 17 00:00:00 2001
From: Teon Banek <teon.banek@memgraph.io>
Date: Thu, 25 May 2017 15:45:03 +0200
Subject: [PATCH] Don't make an Expansion of single node if it is expanded
Summary:
We would redundantly generate an Expansion for the first node if it was part of
an expand. For example, the pattern `(n) -[r]- (m)` would generate
`Expansion{n}` and `Expansion{n, r, m}`, when only the latter is enough. This
change corrects that behaviour by dropping the first Expansion.
Reviewers: florijan, mislav.bradac
Reviewed By: florijan
Subscribers: pullbot
Differential Revision: https://phabricator.memgraph.io/D412
---
src/query/plan/planner.cpp | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/src/query/plan/planner.cpp b/src/query/plan/planner.cpp
index c698cb2d9..5ef9a1b65 100644
--- a/src/query/plan/planner.cpp
+++ b/src/query/plan/planner.cpp
@@ -593,15 +593,19 @@ LogicalOperator *HandleWriteClause(Clause *clause, LogicalOperator *input_op,
std::vector<Expansion> NormalizePatterns(
const std::vector<Pattern *> &patterns) {
std::vector<Expansion> expansions;
- auto collect_node = [&](auto *node) {
- expansions.emplace_back(Expansion{node});
- };
+ auto ignore_node = [&](auto *node) {};
auto collect_expansion = [&](auto *prev_node, auto *edge,
auto *current_node) {
expansions.emplace_back(Expansion{prev_node, edge, current_node});
};
for (const auto &pattern : patterns) {
- ForeachPattern(*pattern, collect_node, collect_expansion);
+ if (pattern->atoms_.size() == 1U) {
+ auto *node = dynamic_cast<NodeAtom *>(pattern->atoms_[0]);
+ debug_assert(node, "First pattern atom is not a node");
+ expansions.emplace_back(Expansion{node});
+ } else {
+ ForeachPattern(*pattern, ignore_node, collect_expansion);
+ }
}
return expansions;
}