Let the Modification Executor also produce data, even if no FullCount is used.

mchacki · mchacki · commit b1c6af5674de · 2020-03-04T09:34:09.000+01:00
diff --git a/arangod/Aql/ModificationExecutor.cpp b/arangod/Aql/ModificationExecutor.cpp
@@ -201,7 +201,6 @@ template <typename FetcherType, typename ModifierType>
     doCollect(input, output.numRowsLeft());
     upstreamState = input.upstreamState();
   }
-
   if (_modifier.nrOfOperations() > 0) {
     _modifier.transact();
 
@@ -234,7 +233,10 @@ template <typename FetcherType, typename ModifierType>
 
   // only produce at most output.numRowsLeft() many results
   ExecutorState upstreamState = input.upstreamState();
-  while (input.hasDataRow() && call.needSkipMore()) {
+  // These executors need to be executed on HARD LIMIT 0.
+  // If we do a fullCount or not.
+  while (input.hasDataRow() &&
+         (call.getOffset() > 0 || (call.getLimit() == 0 && call.hasHardLimit()))) {
     _modifier.reset();
     size_t toSkip = call.getOffset();
     if (call.getLimit() == 0 && call.hasHardLimit()) {
@@ -266,8 +268,10 @@ template <typename FetcherType, typename ModifierType>
         stats.addWritesExecuted(_modifier.nrOfWritesExecuted());
         stats.addWritesIgnored(_modifier.nrOfWritesIgnored());
       }
-
-      call.didSkip(_modifier.nrOfOperations());
+      if (call.needSkipMore()) {
+        // We only need to report skip, if we actually skip.
+        call.didSkip(_modifier.nrOfOperations());
+      }
     }
   }
 
diff --git a/arangod/Aql/SkipResult.cpp b/arangod/Aql/SkipResult.cpp
@@ -45,6 +45,14 @@ auto SkipResult::didSkip(size_t skipped) -> void {
   _skipped.back() += skipped;
 }
 
+auto SkipResult::didSkipSubquery(size_t skipped, size_t depth) -> void {
+  TRI_ASSERT(!_skipped.empty());
+  TRI_ASSERT(_skipped.size() > depth + 1);
+  size_t index = _skipped.size() - depth - 2;
+  size_t& localSkip = _skipped.at(index);
+  localSkip += skipped;
+}
+
 auto SkipResult::nothingSkipped() const noexcept -> bool {
   TRI_ASSERT(!_skipped.empty());
   return std::all_of(_skipped.begin(), _skipped.end(),
diff --git a/arangod/Aql/SkipResult.h b/arangod/Aql/SkipResult.h
@@ -52,6 +52,8 @@ class SkipResult {
 
   auto didSkip(size_t skipped) -> void;
 
+  auto didSkipSubquery(size_t skipped, size_t depth) -> void;
+
   auto nothingSkipped() const noexcept -> bool;
 
   auto toVelocyPack(arangodb::velocypack::Builder& builder) const noexcept -> void;
