refactor: Revert "perf: Remove unnecessary caches (#5439)" (#7359)

Co-authored-by: Bart <11445373+bthomee@users.noreply.github.com>

cfg/xrpld-example.cfg

@@ -953,6 +953,21 @@
 #
 #   Optional keys for NuDB and RocksDB:
 #
+#       cache_size          Size of cache for database records. Default is 16384.
+#                           Setting this value to 0 will use the default value.
+#
+#       cache_age           Length of time in minutes to keep database records
+#                           cached. Default is 5 minutes. Setting this value to
+#                           0 will use the default value.
+#
+#                           Note: if cache_size or cache_age is not specified,
+#                           default values will be used for the unspecified
+#                           parameter.
+#
+#                           Note: the cache will not be created if online_delete
+#                           is specified, because the rotating NodeStore does
+#                           not use this cache).
+#
 #       fast_load           Boolean. If set, load the last persisted ledger
 #                           from disk upon process start before syncing to
 #                           the network. This is likely to improve performance

include/xrpl/nodestore/Database.h

@@ -131,6 +131,10 @@ public:
         std::uint32_t ledgerSeq,
         std::function<void(std::shared_ptr<NodeObject> const&)>&& callback);
 
+    /** Remove expired entries from the positive and negative caches. */
+    virtual void
+    sweep() = 0;
+
     /** Gather statistics pertaining to read and write activities.
      *
      * @param obj Json object reference into which to place counters.

include/xrpl/nodestore/detail/DatabaseNodeImp.h

@@ -22,6 +22,32 @@ public:
         beast::Journal j)
         : Database(scheduler, readThreads, config, j), backend_(std::move(backend))
     {
+        std::optional<int> cacheSize, cacheAge;
+
+        if (config.exists("cache_size"))
+        {
+            cacheSize = get<int>(config, "cache_size");
+            if (cacheSize.value() < 0)
+                Throw<std::runtime_error>("Specified negative value for cache_size");
+        }
+
+        if (config.exists("cache_age"))
+        {
+            cacheAge = get<int>(config, "cache_age");
+            if (cacheAge.value() < 0)
+                Throw<std::runtime_error>("Specified negative value for cache_age");
+        }
+
+        if (cacheSize.has_value() || cacheAge.has_value())
+        {
+            cache_ = std::make_shared<TaggedCache<uint256, NodeObject>>(
+                "DatabaseNodeImp",
+                cacheSize.value_or(0),
+                std::chrono::minutes(cacheAge.value_or(0)),
+                stopwatch(),
+                j);
+        }
+
         XRPL_ASSERT(
             backend_,
             "xrpl::NodeStore::DatabaseNodeImp::DatabaseNodeImp : non-null "
@@ -73,7 +99,13 @@ public:
         std::uint32_t ledgerSeq,
         std::function<void(std::shared_ptr<NodeObject> const&)>&& callback) override;
 
+    void
+    sweep() override;
+
 private:
+    // Cache for database objects. This cache is not always initialized. Check
+    // for null before using.
+    std::shared_ptr<TaggedCache<uint256, NodeObject>> cache_;
     // Persistent key/value storage
     std::shared_ptr<Backend> backend_;
 

include/xrpl/nodestore/detail/DatabaseRotatingImp.h

@@ -55,6 +55,9 @@ public:
     void
     sync() override;
 
+    void
+    sweep() override;
+
 private:
     std::shared_ptr<Backend> writableBackend_;
     std::shared_ptr<Backend> archiveBackend_;

src/libxrpl/nodestore/DatabaseNodeImp.cpp

@@ -24,6 +24,13 @@ DatabaseNodeImp::store(NodeObjectType type, Blob&& data, uint256 const& hash, st
 
     auto obj = NodeObject::createObject(type, std::move(data), hash);
     backend_->store(obj);
+    if (cache_)
+    {
+        // After the store, replace a negative cache entry if there is one
+        cache_->canonicalize(hash, obj, [](std::shared_ptr<NodeObject> const& n) {
+            return n->getType() == NodeObjectType::Dummy;
+        });
+    }
 }
 
 void
@@ -32,9 +39,25 @@ DatabaseNodeImp::asyncFetch(
     std::uint32_t ledgerSeq,
     std::function<void(std::shared_ptr<NodeObject> const&)>&& callback)
 {
+    if (cache_)
+    {
+        std::shared_ptr<NodeObject> const obj = cache_->fetch(hash);
+        if (obj)
+        {
+            callback(obj->getType() == NodeObjectType::Dummy ? nullptr : obj);
+            return;
+        }
+    }
     Database::asyncFetch(hash, ledgerSeq, std::move(callback));
 }
 
+void
+DatabaseNodeImp::sweep()
+{
+    if (cache_)
+        cache_->sweep();
+}
+
 std::shared_ptr<NodeObject>
 DatabaseNodeImp::fetchNodeObject(
     uint256 const& hash,
@@ -42,32 +65,58 @@ DatabaseNodeImp::fetchNodeObject(
     FetchReport& fetchReport,
     bool duplicate)
 {
-    std::shared_ptr<NodeObject> nodeObject = nullptr;
-    Status status = Status::Ok;
+    std::shared_ptr<NodeObject> nodeObject = cache_ ? cache_->fetch(hash) : nullptr;
+    if (!nodeObject)
+    {
+        JLOG(j_.trace()) << "fetchNodeObject " << hash << ": record not "
+                         << (cache_ ? "cached" : "found");
 
-    try
-    {
-        status = backend_->fetch(hash, &nodeObject);
-    }
-    catch (std::exception const& e)
-    {
-        JLOG(j_.fatal()) << "fetchNodeObject " << hash
-                         << ": Exception fetching from backend: " << e.what();
-        rethrow();
-    }
+        Status status = Status::Ok;
+        try
+        {
+            status = backend_->fetch(hash, &nodeObject);
+        }
+        catch (std::exception const& e)
+        {
+            JLOG(j_.fatal()) << "fetchNodeObject " << hash
+                             << ": Exception fetching from backend: " << e.what();
+            rethrow();
+        }
 
-    switch (status)
+        switch (status)
+        {
+            case Status::Ok:
+                if (cache_)
+                {
+                    if (nodeObject)
+                    {
+                        cache_->canonicalizeReplaceClient(hash, nodeObject);
+                    }
+                    else
+                    {
+                        auto notFound = NodeObject::createObject(NodeObjectType::Dummy, {}, hash);
+                        cache_->canonicalizeReplaceClient(hash, notFound);
+                        if (notFound->getType() != NodeObjectType::Dummy)
+                            nodeObject = notFound;
+                    }
+                }
+                break;
+            case Status::NotFound:
+                break;
+            case Status::DataCorrupt:
+                JLOG(j_.fatal()) << "fetchNodeObject " << hash << ": nodestore data is corrupted";
+                break;
+            default:
+                JLOG(j_.warn()) << "fetchNodeObject " << hash << ": backend returns unknown result "
+                                << static_cast<int>(status);
+                break;
+        }
+    }
+    else
     {
-        case Status::Ok:
-        case Status::NotFound:
-            break;
-        case Status::DataCorrupt:
-            JLOG(j_.fatal()) << "fetchNodeObject " << hash << ": nodestore data is corrupted";
-            break;
-        default:
-            JLOG(j_.warn()) << "fetchNodeObject " << hash << ": backend returns unknown result "
-                            << static_cast<int>(status);
-            break;
+        JLOG(j_.trace()) << "fetchNodeObject " << hash << ": record found in cache";
+        if (nodeObject->getType() == NodeObjectType::Dummy)
+            nodeObject.reset();
     }
 
     if (nodeObject)

src/libxrpl/nodestore/DatabaseRotatingImp.cpp

@@ -113,6 +113,12 @@ DatabaseRotatingImp::store(NodeObjectType type, Blob&& data, uint256 const& hash
     storeStats(1, nObj->getData().size());
 }
 
+void
+DatabaseRotatingImp::sweep()
+{
+    // Nothing to do.
+}
+
 std::shared_ptr<NodeObject>
 DatabaseRotatingImp::fetchNodeObject(
     uint256 const& hash,

src/test/app/SHAMapStore_test.cpp

@@ -520,6 +520,25 @@ public:
         /////////////////////////////////////////////////////////////
         // Create NodeStore with two backends to allow online deletion of data.
         // Normally, SHAMapStoreImp handles all these details.
+        auto nscfg = env.app().config().section(ConfigSection::nodeDatabase());
+
+        // Provide default values.
+        if (!nscfg.exists("cache_size"))
+        {
+            nscfg.set(
+                "cache_size",
+                std::to_string(
+                    env.app().config().getValueFor(SizedItem::TreeCacheSize, std::nullopt)));
+        }
+
+        if (!nscfg.exists("cache_age"))
+        {
+            nscfg.set(
+                "cache_age",
+                std::to_string(
+                    env.app().config().getValueFor(SizedItem::TreeCacheAge, std::nullopt)));
+        }
+
         NodeStoreScheduler scheduler(env.app().getJobQueue());
 
         std::string const writableDb = "write";
@@ -528,7 +547,6 @@ public:
         auto archiveBackend = makeBackendRotating(env, scheduler, archiveDb);
 
         static constexpr int kReadThreads = 4;
-        auto nscfg = env.app().config().section(ConfigSection::nodeDatabase());
         auto dbr = std::make_unique<NodeStore::DatabaseRotatingImp>(
             scheduler,
             kReadThreads,

src/xrpld/app/main/Application.cpp

@@ -998,6 +998,10 @@ public:
             JLOG(journal_.debug()) << "MasterTransaction sweep.  Size before: " << oldMasterTxSize
                                    << "; size after: " << masterTxCache.size();
         }
+        {
+            // Sweep NodeStore database cache(s), if enabled.
+            getNodeStore().sweep();
+        }
         {
             std::size_t const oldLedgerMasterCacheSize = getLedgerMaster().getFetchPackCacheSize();
 

src/xrpld/app/misc/SHAMapStoreImp.cpp

@@ -165,6 +165,22 @@ std::unique_ptr<NodeStore::Database>
 SHAMapStoreImp::makeNodeStore(int readThreads)
 {
     auto nscfg = app_.config().section(ConfigSection::nodeDatabase());
+
+    // Provide default values.
+    if (!nscfg.exists("cache_size"))
+    {
+        nscfg.set(
+            "cache_size",
+            std::to_string(app_.config().getValueFor(SizedItem::TreeCacheSize, std::nullopt)));
+    }
+
+    if (!nscfg.exists("cache_age"))
+    {
+        nscfg.set(
+            "cache_age",
+            std::to_string(app_.config().getValueFor(SizedItem::TreeCacheAge, std::nullopt)));
+    }
+
     std::unique_ptr<NodeStore::Database> db;
 
     if (deleteInterval_ != 0u)
@@ -254,6 +270,8 @@ SHAMapStoreImp::run()
     LedgerIndex lastRotated = stateDb_.getState().lastRotated;
     netOPs_ = &app_.getOPs();
     ledgerMaster_ = &app_.getLedgerMaster();
+    fullBelowCache_ = &(*app_.getNodeFamily().getFullBelowCache());
+    treeNodeCache_ = &(*app_.getNodeFamily().getTreeNodeCache());
 
     if (advisoryDelete_)
         canDelete_ = stateDb_.getCanDelete();
@@ -542,16 +560,16 @@ SHAMapStoreImp::clearCaches(LedgerIndex validatedSeq)
     // Also clear the FullBelowCache so its generation counter is bumped.
     // This prevents stale "full below" markers from persisting across
     // backend rotation/online deletion and interfering with SHAMap sync.
-    app_.getNodeFamily().getFullBelowCache()->clear();
+    fullBelowCache_->clear();
 }
 
 void
 SHAMapStoreImp::freshenCaches()
 {
-    if (freshenCache(*app_.getNodeFamily().getTreeNodeCache()))
+    if (freshenCache(*treeNodeCache_))
+        return;
+    if (freshenCache(app_.getMasterTransaction().getCache()))
         return;
-
-    freshenCache(app_.getMasterTransaction().getCache());
 }
 
 void

src/xrpld/app/misc/SHAMapStoreImp.h

@@ -7,6 +7,8 @@
 #include <xrpl/nodestore/Scheduler.h>
 #include <xrpl/rdb/DatabaseCon.h>
 #include <xrpl/server/State.h>
+#include <xrpl/shamap/FullBelowCache.h>
+#include <xrpl/shamap/TreeNodeCache.h>
 
 #include <atomic>
 #include <chrono>
@@ -93,6 +95,8 @@ private:
     // as of run() or before
     NetworkOPs* netOPs_ = nullptr;
     LedgerMaster* ledgerMaster_ = nullptr;
+    FullBelowCache* fullBelowCache_ = nullptr;
+    TreeNodeCache* treeNodeCache_ = nullptr;
 
     static constexpr auto kNodeStoreName = "NodeStore";