Add batching to writes (#1076)

Fixes #1077

CMakeLists.txt

@@ -184,6 +184,7 @@ if (tests)
     unittests/SubscriptionTests.cpp
     unittests/SubscriptionManagerTests.cpp
     unittests/util/AssertTests.cpp
+    unittests/util/BatchingTests.cpp
     unittests/util/TestObject.cpp
     unittests/util/StringUtils.cpp
     unittests/util/prometheus/CounterTests.cpp

example-config.json

@@ -16,7 +16,8 @@
             //
             // Advanced options. USE AT OWN RISK:
             // ---
-            "core_connections_per_host": 1 // Defaults to 1
+            "core_connections_per_host": 1, // Defaults to 1
+            "write_batch_size": 20 // Defaults to 20
             //
             // Below options will use defaults from cassandra driver if left unspecified.
             // See https://docs.datastax.com/en/developer/cpp-driver/2.17/api/struct.CassCluster/ for details.

src/data/cassandra/SettingsProvider.cpp

@@ -122,8 +122,8 @@ SettingsProvider::parseSettings() const
         config_.valueOr<uint32_t>("max_read_requests_outstanding", settings.maxReadRequestsOutstanding);
     settings.coreConnectionsPerHost =
         config_.valueOr<uint32_t>("core_connections_per_host", settings.coreConnectionsPerHost);
-
     settings.queueSizeIO = config_.maybeValue<uint32_t>("queue_size_io");
+    settings.writeBatchSize = config_.valueOr<std::size_t>("write_batch_size", settings.writeBatchSize);
 
     auto const connectTimeoutSecond = config_.maybeValue<uint32_t>("connect_timeout");
     if (connectTimeoutSecond)

src/data/cassandra/impl/Cluster.cpp

@@ -83,6 +83,7 @@ Cluster::Cluster(Settings const& settings) : ManagedObject{cass_cluster_new(), c
     LOG(log_.info()) << "Threads: " << settings.threads;
     LOG(log_.info()) << "Core connections per host: " << settings.coreConnectionsPerHost;
     LOG(log_.info()) << "IO queue size: " << queueSize;
+    LOG(log_.info()) << "Batched writes auto-chunk size: " << settings.writeBatchSize;
 }
 
 void

src/data/cassandra/impl/Cluster.h

@@ -42,6 +42,8 @@ struct Settings {
     static constexpr std::size_t DEFAULT_CONNECTION_TIMEOUT = 10000;
     static constexpr uint32_t DEFAULT_MAX_WRITE_REQUESTS_OUTSTANDING = 10'000;
     static constexpr uint32_t DEFAULT_MAX_READ_REQUESTS_OUTSTANDING = 100'000;
+    static constexpr std::size_t DEFAULT_BATCH_SIZE = 20;
+
     /**
      * @brief Represents the configuration of contact points for cassandra.
      */
@@ -81,6 +83,9 @@ struct Settings {
     /** @brief The number of connection per host to always have active */
     uint32_t coreConnectionsPerHost = 1u;
 
+    /** @brief Size of batches when writing */
+    std::size_t writeBatchSize = DEFAULT_BATCH_SIZE;
+
     /** @brief Size of the IO queue */
     std::optional<uint32_t> queueSizeIO{};
 

src/data/cassandra/impl/ExecutionStrategy.h

@@ -25,6 +25,7 @@
 #include "data/cassandra/Types.h"
 #include "data/cassandra/impl/AsyncExecutor.h"
 #include "util/Assert.h"
+#include "util/Batching.h"
 #include "util/Expected.h"
 #include "util/log/Logger.h"
 
@@ -59,6 +60,8 @@ class DefaultExecutionStrategy {
     std::uint32_t maxReadRequestsOutstanding_;
     std::atomic_uint32_t numReadRequestsOutstanding_ = 0;
 
+    std::size_t writeBatchSize_;
+
     std::mutex throttleMutex_;
     std::condition_variable throttleCv_;
 
@@ -93,6 +96,7 @@ public:
     )
         : maxWriteRequestsOutstanding_{settings.maxWriteRequestsOutstanding}
         , maxReadRequestsOutstanding_{settings.maxReadRequestsOutstanding}
+        , writeBatchSize_{settings.writeBatchSize}
         , work_{ioc_}
         , handle_{std::cref(handle)}
         , thread_{[this]() { ioc_.run(); }}
@@ -214,22 +218,28 @@ public:
         if (statements.empty())
             return;
 
+        util::forEachBatch(std::move(statements), writeBatchSize_, [this](auto begin, auto end) {
             auto const startTime = std::chrono::steady_clock::now();
+            auto chunk = std::vector<StatementType>{};
+
+            chunk.reserve(std::distance(begin, end));
+            std::move(begin, end, std::back_inserter(chunk));
 
             incrementOutstandingRequestCount();
-
             counters_->registerWriteStarted();
+
             // Note: lifetime is controlled by std::shared_from_this internally
-        AsyncExecutor<std::decay_t<decltype(statements)>, HandleType>::run(
+            AsyncExecutor<std::decay_t<decltype(chunk)>, HandleType>::run(
                 ioc_,
                 handle_,
-            std::move(statements),
+                std::move(chunk),
                 [this, startTime](auto const&) {
                     decrementOutstandingRequestCount();
                     counters_->registerWriteFinished(startTime);
                 },
                 [this]() { counters_->registerWriteRetry(); }
             );
+        });
     }
 
     /**

src/util/Batching.h

@@ -0,0 +1,45 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2024, the clio developers.
+
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#pragma once
+
+#include "util/Assert.h"
+
+#include <algorithm>
+#include <cstdint>
+#include <ranges>
+
+namespace util {
+
+void
+forEachBatch(std::ranges::forward_range auto&& container, std::size_t batchSize, auto&& fn)
+{
+    ASSERT(batchSize > 0, "Batch size must be greater than 0");
+
+    auto const totalSize = container.size();
+    auto const batches = totalSize / batchSize + (totalSize % batchSize ? 1 : 0);
+
+    for (auto i = 0u; i < batches; ++i) {
+        auto const start = i * batchSize;
+        auto const end = std::min(start + batchSize, totalSize);
+        fn(container.begin() + start, container.begin() + end);
+    }
+}
+
+}  // namespace util

unittests/util/BatchingTests.cpp

@@ -0,0 +1,76 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of clio: https://github.com/XRPLF/clio
+    Copyright (c) 2024, the clio developers.
+
+    Permission to use, copy, modify, and distribute this software for any
+    purpose with or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL,  DIRECT,  INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include "util/Batching.h"
+
+#include <gtest/gtest.h>
+
+#include <algorithm>
+
+TEST(BatchingTests, simpleBatch)
+{
+    std::vector<int> const input{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+    std::vector<int> output;
+
+    util::forEachBatch(input, 3, [&](auto begin, auto end) {
+        std::copy(begin, end, std::back_inserter(output));
+        EXPECT_LE(std::distance(begin, end), 3);
+    });
+
+    EXPECT_EQ(input, output);
+}
+
+TEST(BatchingTests, simpleBatchEven)
+{
+    std::vector<int> const input{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+    std::vector<int> output;
+
+    util::forEachBatch(input, 2, [&](auto begin, auto end) {
+        std::copy(begin, end, std::back_inserter(output));
+        EXPECT_LE(std::distance(begin, end), 2);
+    });
+
+    EXPECT_EQ(input, output);
+}
+
+TEST(BatchingTests, batchSizeBiggerThanInput)
+{
+    std::vector<int> const input{1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
+    std::vector<int> output;
+
+    util::forEachBatch(input, 20, [&](auto begin, auto end) {
+        std::copy(begin, end, std::back_inserter(output));
+        EXPECT_LE(std::distance(begin, end), 20);
+    });
+
+    EXPECT_EQ(input, output);
+}
+
+TEST(BatchingTests, emptyInput)
+{
+    std::vector<int> const input{};
+    std::vector<int> output;
+
+    util::forEachBatch(input, 20, [&](auto begin, auto end) {
+        std::copy(begin, end, std::back_inserter(output));
+        ASSERT_FALSE(true) << "Should not be called";
+    });
+
+    EXPECT_EQ(input, output);
+}