Merge pull request #4700 from Daniel-B-Smith/range-read-copy

Remove unnecessary copy of KVS entries into range read response
apple · Apr 22, 2021 · e3ce689 · e3ce689
2 parents 77af97c + aeb4938
commit e3ce689
Showing 1 changed file with 6 additions and 3 deletions.
diff --git a/fdbserver/storageserver.actor.cpp b/fdbserver/storageserver.actor.cpp
@@ -1437,7 +1437,7 @@ ACTOR Future<Void> getShardStateQ(StorageServer* data, GetShardStateRequest req)
 void merge(Arena& arena,
            VectorRef<KeyValueRef, VecSerStrategy::String>& output,
            VectorRef<KeyValueRef> const& vm_output,
-           VectorRef<KeyValueRef> const& base,
+           Standalone<RangeResultRef> const& base,
            int& vCount,
            int limit,
            bool stopAtEndOfBase,
@@ -1448,6 +1448,9 @@ void merge(Arena& arena,
 // start is still inclusive and end is exclusive
 {
 	ASSERT(limit != 0);
+	// Add a dependency of the new arena on the result from the KVS so that we don't have to copy any of the KVS
+	// results.
+	arena.dependsOn(base.arena());
 
 	bool forward = limit > 0;
 	if (!forward)
@@ -1458,7 +1461,7 @@ void merge(Arena& arena,
 	KeyValueRef const* baseEnd = base.end();
 	while (baseStart != baseEnd && vCount > 0 && output.size() < adjustedLimit && accumulatedBytes < limitBytes) {
 		if (forward ? baseStart->key < vm_output[pos].key : baseStart->key > vm_output[pos].key) {
-			output.push_back_deep(arena, *baseStart++);
+			output.push_back(arena, *baseStart++);
 		} else {
 			output.push_back_deep(arena, vm_output[pos]);
 			if (baseStart->key == vm_output[pos].key)
@@ -1469,7 +1472,7 @@ void merge(Arena& arena,
 		accumulatedBytes += sizeof(KeyValueRef) + output.end()[-1].expectedSize();
 	}
 	while (baseStart != baseEnd && output.size() < adjustedLimit && accumulatedBytes < limitBytes) {
-		output.push_back_deep(arena, *baseStart++);
+		output.push_back(arena, *baseStart++);
 		accumulatedBytes += sizeof(KeyValueRef) + output.end()[-1].expectedSize();
 	}
 	if (!stopAtEndOfBase) {