Add behaviour of no updates if vertex is updated with same value (#1791)

src/flags/general.cpp

@@ -131,6 +131,10 @@ DEFINE_uint64(storage_recovery_thread_count,
 DEFINE_bool(storage_enable_schema_metadata, false,
             "Controls whether metadata should be collected about the resident labels and edge types.");
 
+// NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
+DEFINE_bool(storage_delta_on_identical_property_update, true,
+            "Controls whether updating a property with the same value should create a delta object.");
+
 // NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
 DEFINE_bool(telemetry_enabled, false,
             "Set to true to enable telemetry. We collect information about the "

src/flags/general.hpp

@@ -84,6 +84,8 @@ DECLARE_bool(storage_parallel_schema_recovery);
 DECLARE_uint64(storage_recovery_thread_count);
 // NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
 DECLARE_bool(storage_enable_schema_metadata);
+// NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
+DECLARE_bool(storage_delta_on_identical_property_update);
 
 // NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
 DECLARE_bool(telemetry_enabled);

src/memgraph.cpp

@@ -332,7 +332,8 @@ int main(int argc, char **argv) {
                .durability_directory = FLAGS_data_directory + "/rocksdb_durability",
                .wal_directory = FLAGS_data_directory + "/rocksdb_wal"},
       .salient.items = {.properties_on_edges = FLAGS_storage_properties_on_edges,
-                        .enable_schema_metadata = FLAGS_storage_enable_schema_metadata},
+                        .enable_schema_metadata = FLAGS_storage_enable_schema_metadata,
+                        .delta_on_identical_property_update = FLAGS_storage_delta_on_identical_property_update},
       .salient.storage_mode = memgraph::flags::ParseStorageMode()};
   spdlog::info("config recover on startup {}, flags {} {}", db_config.durability.recover_on_startup,
                FLAGS_storage_recover_on_startup, FLAGS_data_recovery_on_startup);

src/query/frontend/stripped.cpp

@@ -1,4 +1,4 @@
-// Copyright 2023 Memgraph Ltd.
+// Copyright 2024 Memgraph Ltd.
 //
 // Use of this software is governed by the Business Source License
 // included in the file licenses/BSL.txt; by using this file, you agree to be bound by the terms of the Business Source

src/query/plan/operator.cpp

@@ -329,7 +329,7 @@ CreateExpand::CreateExpand(NodeCreationInfo node_info, EdgeCreationInfo edge_inf
 ACCEPT_WITH_INPUT(CreateExpand)
 
 UniqueCursorPtr CreateExpand::MakeCursor(utils::MemoryResource *mem) const {
-  memgraph::metrics::IncrementCounter(memgraph::metrics::CreateNodeOperator);
+  memgraph::metrics::IncrementCounter(memgraph::metrics::CreateExpandOperator);
 
   return MakeUniqueCursorPtr<CreateExpandCursor>(mem, *this, mem);
 }

src/storage/v2/config.hpp

@@ -37,6 +37,7 @@ struct SalientConfig {
   struct Items {
     bool properties_on_edges{true};
     bool enable_schema_metadata{false};
+    bool delta_on_identical_property_update{true};
     friend bool operator==(const Items &lrh, const Items &rhs) = default;
   } items;
 

src/storage/v2/edge_accessor.cpp

@@ -130,9 +130,13 @@ Result<storage::PropertyValue> EdgeAccessor::SetProperty(PropertyId property, co
   if (edge_.ptr->deleted) return Error::DELETED_OBJECT;
   using ReturnType = decltype(edge_.ptr->properties.GetProperty(property));
   std::optional<ReturnType> current_value;
+  const bool skip_duplicate_write = !storage_->config_.salient.items.delta_on_identical_property_update;
   utils::AtomicMemoryBlock atomic_memory_block{
-      [&current_value, &property, &value, transaction = transaction_, edge = edge_]() {
+      [&current_value, &property, &value, transaction = transaction_, edge = edge_, skip_duplicate_write]() {
         current_value.emplace(edge.ptr->properties.GetProperty(property));
+        if (skip_duplicate_write && current_value == value) {
+          return;
+        }
         // We could skip setting the value if the previous one is the same to the new
         // one. This would save some memory as a delta would not be created as well as
         // avoid copying the value. The reason we are not doing that is because the
@@ -184,12 +188,14 @@ Result<std::vector<std::tuple<PropertyId, PropertyValue, PropertyValue>>> EdgeAc
 
   if (edge_.ptr->deleted) return Error::DELETED_OBJECT;
 
+  const bool skip_duplicate_write = !storage_->config_.salient.items.delta_on_identical_property_update;
   using ReturnType = decltype(edge_.ptr->properties.UpdateProperties(properties));
   std::optional<ReturnType> id_old_new_change;
   utils::AtomicMemoryBlock atomic_memory_block{
-      [transaction_ = transaction_, edge_ = edge_, &properties, &id_old_new_change]() {
+      [transaction_ = transaction_, edge_ = edge_, &properties, &id_old_new_change, skip_duplicate_write]() {
         id_old_new_change.emplace(edge_.ptr->properties.UpdateProperties(properties));
         for (auto &[property, old_value, new_value] : *id_old_new_change) {
+          if (skip_duplicate_write && old_value == new_value) continue;
           CreateAndLinkDelta(transaction_, edge_.ptr, Delta::SetPropertyTag(), property, std::move(old_value));
         }
       }};

src/storage/v2/vertex_accessor.cpp

@@ -261,20 +261,31 @@ Result<PropertyValue> VertexAccessor::SetProperty(PropertyId property, const Pro
 
   if (vertex_->deleted) return Error::DELETED_OBJECT;
 
-  auto current_value = vertex_->properties.GetProperty(property);
+  PropertyValue current_value;
-  // We could skip setting the value if the previous one is the same to the new
+  const bool skip_duplicate_write = !storage_->config_.salient.items.delta_on_identical_property_update;
-  // one. This would save some memory as a delta would not be created as well as
-  // avoid copying the value. The reason we are not doing that is because the
-  // current code always follows the logical pattern of "create a delta" and
-  // "modify in-place". Additionally, the created delta will make other
-  // transactions get a SERIALIZATION_ERROR.
-
   utils::AtomicMemoryBlock atomic_memory_block{
-      [transaction = transaction_, vertex = vertex_, &value, &property, &current_value]() {
+      [transaction = transaction_, vertex = vertex_, &value, &property, &current_value, skip_duplicate_write]() {
+        current_value = vertex->properties.GetProperty(property);
+        // We could skip setting the value if the previous one is the same to the new
+        // one. This would save some memory as a delta would not be created as well as
+        // avoid copying the value. The reason we are not doing that is because the
+        // current code always follows the logical pattern of "create a delta" and
+        // "modify in-place". Additionally, the created delta will make other
+        // transactions get a SERIALIZATION_ERROR.
+        if (skip_duplicate_write && current_value == value) {
+          return true;
+        }
+
         CreateAndLinkDelta(transaction, vertex, Delta::SetPropertyTag(), property, current_value);
         vertex->properties.SetProperty(property, value);
+
+        return false;
       }};
-  std::invoke(atomic_memory_block);
+  const bool early_exit = std::invoke(atomic_memory_block);
+
+  if (early_exit) {
+    return std::move(current_value);
+  }
 
   if (transaction_->constraint_verification_info) {
     if (!value.IsNull()) {
@@ -339,27 +350,29 @@ Result<std::vector<std::tuple<PropertyId, PropertyValue, PropertyValue>>> Vertex
 
   if (vertex_->deleted) return Error::DELETED_OBJECT;
 
+  const bool skip_duplicate_update = storage_->config_.salient.items.delta_on_identical_property_update;
   using ReturnType = decltype(vertex_->properties.UpdateProperties(properties));
   std::optional<ReturnType> id_old_new_change;
-  utils::AtomicMemoryBlock atomic_memory_block{
+  utils::AtomicMemoryBlock atomic_memory_block{[storage = storage_, transaction = transaction_, vertex = vertex_,
-      [storage = storage_, transaction = transaction_, vertex = vertex_, &properties, &id_old_new_change]() {
+                                                &properties, &id_old_new_change, skip_duplicate_update]() {
-        id_old_new_change.emplace(vertex->properties.UpdateProperties(properties));
+    id_old_new_change.emplace(vertex->properties.UpdateProperties(properties));
-        if (!id_old_new_change.has_value()) {
+    if (!id_old_new_change.has_value()) {
-          return;
+      return;
+    }
+    for (auto &[id, old_value, new_value] : *id_old_new_change) {
+      storage->indices_.UpdateOnSetProperty(id, new_value, vertex, *transaction);
+      if (skip_duplicate_update && old_value == new_value) continue;
+      CreateAndLinkDelta(transaction, vertex, Delta::SetPropertyTag(), id, std::move(old_value));
+      transaction->manyDeltasCache.Invalidate(vertex, id);
+      if (transaction->constraint_verification_info) {
+        if (!new_value.IsNull()) {
+          transaction->constraint_verification_info->AddedProperty(vertex);
+        } else {
+          transaction->constraint_verification_info->RemovedProperty(vertex);
         }
-        for (auto &[id, old_value, new_value] : *id_old_new_change) {
+      }
-          storage->indices_.UpdateOnSetProperty(id, new_value, vertex, *transaction);
+    }
-          CreateAndLinkDelta(transaction, vertex, Delta::SetPropertyTag(), id, std::move(old_value));
+  }};
-          transaction->manyDeltasCache.Invalidate(vertex, id);
-          if (transaction->constraint_verification_info) {
-            if (!new_value.IsNull()) {
-              transaction->constraint_verification_info->AddedProperty(vertex);
-            } else {
-              transaction->constraint_verification_info->RemovedProperty(vertex);
-            }
-          }
-        }
-      }};
   std::invoke(atomic_memory_block);
 
   return id_old_new_change.has_value() ? std::move(id_old_new_change.value()) : ReturnType{};

src/utils/atomic_memory_block.hpp

@@ -29,12 +29,10 @@ class [[nodiscard]] AtomicMemoryBlock {
   AtomicMemoryBlock &operator=(AtomicMemoryBlock &&) = delete;
   ~AtomicMemoryBlock() = default;
 
-  void operator()() {
+  auto operator()() -> std::invoke_result_t<Callable> {
-    {
+    auto check_on_exit = OnScopeExit{[&] { total_memory_tracker.DoCheck(); }};
-      utils::MemoryTracker::OutOfMemoryExceptionBlocker oom_blocker;
+    utils::MemoryTracker::OutOfMemoryExceptionBlocker oom_blocker;
-      function_();
+    return function_();
-    }
-    total_memory_tracker.DoCheck();
   }
 
  private:

src/utils/on_scope_exit.hpp

@@ -35,7 +35,7 @@ namespace memgraph::utils {
  *     // long block of code, might throw an exception
  * }
  */
-template <typename Callable>
+template <std::invocable Callable>
 class [[nodiscard]] OnScopeExit {
  public:
   template <typename U>
@@ -46,7 +46,7 @@ class [[nodiscard]] OnScopeExit {
   OnScopeExit &operator=(OnScopeExit const &) = delete;
   OnScopeExit &operator=(OnScopeExit &&) = delete;
   ~OnScopeExit() {
-    if (doCall_) function_();
+    if (doCall_) std::invoke(std::move(function_));
   }
 
   void Disable() { doCall_ = false; }
@@ -57,5 +57,4 @@ class [[nodiscard]] OnScopeExit {
 };
 template <typename Callable>
 OnScopeExit(Callable &&) -> OnScopeExit<Callable>;
-
 }  // namespace memgraph::utils

tests/e2e/CMakeLists.txt

@@ -77,6 +77,7 @@ add_subdirectory(garbage_collection)
 add_subdirectory(query_planning)
 add_subdirectory(awesome_functions)
 add_subdirectory(high_availability)
+add_subdirectory(concurrency)
 
 add_subdirectory(replication_experimental)
 

tests/e2e/concurrency/CMakeLists.txt

@@ -0,0 +1,6 @@
+function(copy_concurrency_e2e_python_files FILE_NAME)
+    copy_e2e_python_files(concurrency ${FILE_NAME})
+endfunction()
+
+copy_concurrency_e2e_python_files(common.py)
+copy_concurrency_e2e_python_files(concurrency.py)

tests/e2e/concurrency/common.py

@@ -0,0 +1,60 @@
+# Copyright 2023 Memgraph Ltd.
+#
+# Use of this software is governed by the Business Source License
+# included in the file licenses/BSL.txt; by using this file, you agree to be bound by the terms of the Business Source
+# License, and you may not use this file except in compliance with the Business Source License.
+#
+# As of the Change Date specified in that file, in accordance with
+# the Business Source License, use of this software will be governed
+# by the Apache License, Version 2.0, included in the file
+# licenses/APL.txt.
+
+import typing
+
+import mgclient
+import pytest
+
+
+def execute_and_fetch_all(cursor: mgclient.Cursor, query: str, params: dict = {}) -> typing.List[tuple]:
+    cursor.execute(query, params)
+    return cursor.fetchall()
+
+
+def execute_and_fetch_all_with_commit(
+    connection: mgclient.Connection, query: str, params: dict = {}
+) -> typing.List[tuple]:
+    cursor = connection.cursor()
+    cursor.execute(query, params)
+    results = cursor.fetchall()
+    connection.commit()
+    return results
+
+
+@pytest.fixture
+def first_connection(**kwargs) -> mgclient.Connection:
+    connection = mgclient.connect(host="localhost", port=7687, **kwargs)
+    connection.autocommit = True
+    cursor = connection.cursor()
+    execute_and_fetch_all(cursor, "USE DATABASE memgraph")
+    try:
+        execute_and_fetch_all(cursor, "DROP DATABASE clean")
+    except:
+        pass
+    execute_and_fetch_all(cursor, "MATCH (n) DETACH DELETE n")
+    connection.autocommit = False
+    yield connection
+
+
+@pytest.fixture
+def second_connection(**kwargs) -> mgclient.Connection:
+    connection = mgclient.connect(host="localhost", port=7687, **kwargs)
+    connection.autocommit = True
+    cursor = connection.cursor()
+    execute_and_fetch_all(cursor, "USE DATABASE memgraph")
+    try:
+        execute_and_fetch_all(cursor, "DROP DATABASE clean")
+    except:
+        pass
+    execute_and_fetch_all(cursor, "MATCH (n) DETACH DELETE n")
+    connection.autocommit = False
+    yield connection

tests/e2e/concurrency/concurrency.py

@@ -0,0 +1,57 @@
+# Copyright 2023 Memgraph Ltd.
+#
+# Use of this software is governed by the Business Source License
+# included in the file licenses/BSL.txt; by using this file, you agree to be bound by the terms of the Business Source
+# License, and you may not use this file except in compliance with the Business Source License.
+#
+# As of the Change Date specified in that file, in accordance with
+# the Business Source License, use of this software will be governed
+# by the Apache License, Version 2.0, included in the file
+# licenses/APL.txt.
+
+import sys
+
+import pytest
+from common import execute_and_fetch_all, first_connection, second_connection
+
+
+def test_concurrency_if_no_delta_on_same_node_property_update(first_connection, second_connection):
+    m1c = first_connection.cursor()
+    m2c = second_connection.cursor()
+
+    execute_and_fetch_all(m1c, "CREATE (:Node {prop: 1})")
+    first_connection.commit()
+
+    test_has_error = False
+    try:
+        m1c.execute("MATCH (n) SET n.prop = 1")
+        m2c.execute("MATCH (n) SET n.prop = 1")
+        first_connection.commit()
+        second_connection.commit()
+    except Exception as e:
+        test_has_error = True
+
+    assert test_has_error is False
+
+
+def test_concurrency_if_no_delta_on_same_edge_property_update(first_connection, second_connection):
+    m1c = first_connection.cursor()
+    m2c = second_connection.cursor()
+
+    execute_and_fetch_all(m1c, "CREATE ()-[:TYPE {prop: 1}]->()")
+    first_connection.commit()
+
+    test_has_error = False
+    try:
+        m1c.execute("MATCH (n)-[r]->(m) SET r.prop = 1")
+        m2c.execute("MATCH (n)-[r]->(m) SET n.prop = 1")
+        first_connection.commit()
+        second_connection.commit()
+    except Exception as e:
+        test_has_error = True
+
+    assert test_has_error is False
+
+
+if __name__ == "__main__":
+    sys.exit(pytest.main([__file__, "-rA"]))

tests/e2e/concurrency/workloads.yaml

@@ -0,0 +1,14 @@
+concurrency_cluster: &concurrency_cluster
+  cluster:
+    main:
+      args: ["--bolt-port", "7687", "--log-level=TRACE", "--storage-delta-on-identical-property-update=false"]
+      log_file: "concurrency.log"
+      setup_queries: []
+      validation_queries: []
+
+
+workloads:
+  - name: "Concurrency"
+    binary: "tests/e2e/pytest_runner.sh"
+    args: ["concurrency/concurrency.py"]
+    <<: *concurrency_cluster

tests/e2e/configuration/default_config.py

@@ -141,6 +141,11 @@ startup_config_dict = {
         "1",
         "The time duration between two replica checks/pings. If < 1, replicas will NOT be checked at all. NOTE: The MAIN instance allocates a new thread for each REPLICA.",
     ),
+    "storage_delta_on_identical_property_update": (
+        "true",
+        "true",
+        "Controls whether updating a property with the same value should create a delta object.",
+    ),
     "storage_gc_cycle_sec": ("30", "30", "Storage garbage collector interval (in seconds)."),
     "storage_python_gc_cycle_sec": ("180", "180", "Storage python full garbage collection interval (in seconds)."),
     "storage_items_per_batch": (