Extract to helper function

ad-freiburg · Feb 21, 2025 · 1b75e84 · 1b75e84
1 parent 9699068
commit 1b75e84
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Showing 2 changed files with 39 additions and 24 deletions.
diff --git a/src/engine/QueryPlanner.cpp b/src/engine/QueryPlanner.cpp
@@ -2047,6 +2047,41 @@ auto QueryPlanner::createSpatialJoin(const SubtreePlan& a, const SubtreePlan& b,
   return plan;
 }
 
+// _____________________________________________________________________________________________________________________
+
+namespace {
+// Helper function that maps the indices from the unions' columns to the
+// children's columns if possible. Otherwise the entry in `jcs` is dropped.
+std::pair<QueryPlanner::JoinColumns, QueryPlanner::JoinColumns>
+mapColumnsInUnion(size_t columnIndex, const Union& unionOperation,
+                  const QueryPlanner::JoinColumns& jcs) {
+  QueryPlanner::JoinColumns leftMapping;
+  leftMapping.reserve(jcs.size());
+  QueryPlanner::JoinColumns rightMapping;
+  rightMapping.reserve(jcs.size());
+  auto mapColumns = [columnIndex, &unionOperation](
+                        bool isLeft, std::array<ColumnIndex, 2> columns)
+      -> std::optional<array<ColumnIndex, 2>> {
+    ColumnIndex& column = columns.at(columnIndex);
+    auto tmp = unionOperation.getOriginalColumn(isLeft, column);
+    if (tmp.has_value()) {
+      column = tmp.value();
+      return columns;
+    }
+    return std::nullopt;
+  };
+  for (const auto& joinColumns : jcs) {
+    if (auto mappedColumn = mapColumns(true, joinColumns)) {
+      leftMapping.push_back(mappedColumn.value());
+    }
+    if (auto mappedColumn = mapColumns(false, joinColumns)) {
+      rightMapping.push_back(mappedColumn.value());
+    }
+  }
+  return {std::move(leftMapping), std::move(rightMapping)};
+}
+}  // namespace
+
 // _____________________________________________________________________________________________________________________
 auto QueryPlanner::applyJoinDistributivelyToUnion(SubtreePlan a, SubtreePlan b,
                                                   const JoinColumns& jcs) const
@@ -2069,29 +2104,8 @@ auto QueryPlanner::applyJoinDistributivelyToUnion(SubtreePlan a, SubtreePlan b,
     const auto& leftCandidate = flipped ? other : tmpPlan;
     const auto& rightCandidate = flipped ? tmpPlan : clonedOther;
 
-    JoinColumns leftMapping;
-    leftMapping.reserve(jcs.size());
-    JoinColumns rightMapping;
-    rightMapping.reserve(jcs.size());
-    auto mapColumns = [flipped, &unionOperation](
-                          bool isLeft, std::array<ColumnIndex, 2> columns)
-        -> std::optional<array<ColumnIndex, 2>> {
-      ColumnIndex& column = columns.at(flipped);
-      auto tmp = unionOperation->getOriginalColumn(isLeft, column);
-      if (tmp.has_value()) {
-        column = tmp.value();
-        return columns;
-      }
-      return std::nullopt;
-    };
-    for (const auto& joinColumns : jcs) {
-      if (auto mappedColumn = mapColumns(true, joinColumns)) {
-        leftMapping.push_back(mappedColumn.value());
-      }
-      if (auto mappedColumn = mapColumns(false, joinColumns)) {
-        rightMapping.push_back(mappedColumn.value());
-      }
-    }
+    auto [leftMapping, rightMapping] =
+        mapColumnsInUnion(flipped, *unionOperation, jcs);
 
     tmpPlan._qet = unionOperation->leftChild();
     auto joinedLeft =

diff --git a/src/engine/QueryPlanner.h b/src/engine/QueryPlanner.h
@@ -23,7 +23,6 @@ class QueryPlanner {
   using CancellationHandle = ad_utility::SharedCancellationHandle;
   template <typename T>
   using vector = std::vector<T>;
-  using JoinColumns = std::vector<std::array<ColumnIndex, 2>>;
 
   ParsedQuery::DatasetClauses activeDatasetClauses_;
   // The variable of the innermost `GRAPH ?var` clause that the planner
@@ -33,6 +32,8 @@ class QueryPlanner {
   std::optional<Variable> activeGraphVariable_;
 
  public:
+  using JoinColumns = std::vector<std::array<ColumnIndex, 2>>;
+
   explicit QueryPlanner(QueryExecutionContext* qec,
                         CancellationHandle cancellationHandle);