More predictable LevelDB latency, LevelDB write batching.

src/cpp/ripple/Application.cpp

@@ -180,8 +180,6 @@ void Application::setup()
 			options.filter_policy = leveldb::NewBloomFilterPolicy(10);
 		if (theConfig.LDB_IMPORT)
 			options.write_buffer_size = 32 << 20;
-		options.write_buffer_size = std::max(options.write_buffer_size,
-			static_cast<size_t>(theConfig.getSize(siLDBWriteSize) << 20));
 		leveldb::Status status = leveldb::DB::Open(options, (theConfig.DATA_DIR / "hashnode").string(), &mHashNodeLDB);
 		if (!status.ok() || !mHashNodeLDB)
 		{

src/cpp/ripple/Config.cpp

@@ -516,7 +516,6 @@ int Config::getSize(SizedItemName item)
 		{ siHashNodeDBCache,	{	24,		48,		64,		128,		256		} },
 		{ siTxnDBCache,			{	4,		12,		48,		96,			192		} },
 		{ siLgrDBCache,			{	4,		8,		32,		64,			128		} },
-		{ siLDBWriteSize,		{	8,		16,		32,		64,			128		} }
 	};
 
 	for (int i = 0; i < (sizeof(sizeTable) / sizeof(SizedItem)); ++i)

src/cpp/ripple/Config.h

@@ -68,7 +68,6 @@ enum SizedItemName
 	siHashNodeDBCache,
 	siTxnDBCache,
 	siLgrDBCache,
-	siLDBWriteSize
 };
 
 struct SizedItem

src/cpp/ripple/HashedObject.cpp

@@ -1,8 +1,8 @@
-
 #include "HashedObject.h"
 
 #ifdef USE_LEVELDB
 #include "leveldb/db.h"
+#include "leveldb/write_batch.h"
 #endif
 
 #include <boost/lexical_cast.hpp>
@@ -68,34 +68,72 @@ bool HashedObjectStore::storeLevelDB(HashedObjectType type, uint32 index,
 	HashedObject::pointer object = boost::make_shared<HashedObject>(type, index, data, hash);
 	if (!mCache.canonicalize(hash, object))
 	{
-		LoadEvent::autoptr event(theApp->getJobQueue().getLoadEventAP(jtHO_WRITE, "HOS::store"));
+		boost::mutex::scoped_lock sl(mWriteMutex);
+		mWriteSet.push_back(object);
+		if (!mWritePending)
+		{
+			mWritePending = true;
+			theApp->getJobQueue().addJob(jtWRITE, "HashedObject::store",
+				BIND_TYPE(&HashedObjectStore::bulkWriteLevelDB, this));
+		}
+	}
+	mNegativeCache.del(hash);
+	return true;
+}
 
-		std::vector<unsigned char> rawData(9 + data.size());
+void HashedObjectStore::bulkWriteLevelDB()
+{
+	assert(mLevelDB);
+	while (1)
+	{
+		std::vector< boost::shared_ptr<HashedObject> > set;
+		set.reserve(128);
+
+		{
+			boost::mutex::scoped_lock sl(mWriteMutex);
+			mWriteSet.swap(set);
+			assert(mWriteSet.empty());
+			++mWriteGeneration;
+			mWriteCondition.notify_all();
+			if (set.empty())
+			{
+				mWritePending = false;
+				return;
+			}
+		}
+
+		{
+			leveldb::WriteBatch batch;
+
+			BOOST_FOREACH(const boost::shared_ptr<HashedObject>& it, set)
+			{
+				const HashedObject& obj = *it;
+				std::vector<unsigned char> rawData(9 + obj.mData.size());
 				unsigned char* bufPtr = &rawData.front();
 
-		*reinterpret_cast<uint32*>(bufPtr + 0) = ntohl(index);
-		*reinterpret_cast<uint32*>(bufPtr + 4) = ntohl(index);
-		*(bufPtr + 8) = static_cast<unsigned char>(type);
-		memcpy(bufPtr + 9, &data.front(), data.size());
+				*reinterpret_cast<uint32*>(bufPtr + 0) = ntohl(obj.mLedgerIndex);
+				*reinterpret_cast<uint32*>(bufPtr + 4) = ntohl(obj.mLedgerIndex);
+				*(bufPtr + 8) = static_cast<unsigned char>(obj.mType);
+				memcpy(bufPtr + 9, &obj.mData.front(), obj.mData.size());
 
-		leveldb::Status st = theApp->getHashNodeLDB()->Put(leveldb::WriteOptions(),
-			leveldb::Slice(reinterpret_cast<const char *>(hash.begin()), hash.size()),
-			leveldb::Slice(reinterpret_cast<const char *>(bufPtr), 9 + data.size()));
+				batch.Put(leveldb::Slice(reinterpret_cast<const char *>(obj.mHash.begin()), obj.mHash.size()),
+					leveldb::Slice(reinterpret_cast<const char *>(bufPtr), rawData.size()));
+			}
+
+			leveldb::Status st = theApp->getHashNodeLDB()->Write(leveldb::WriteOptions(), &batch);
 			if (!st.ok())
 			{
 				cLog(lsFATAL) << "Failed to store hash node";
 				assert(false);
 			}
 		}
-	else
-		cLog(lsDEBUG) << "HOS: store race";
-	return true;
+	}
 }
 
 HashedObject::pointer HashedObjectStore::retrieveLevelDB(const uint256& hash)
 {
 	HashedObject::pointer obj = mCache.fetch(hash);
-	if (obj)
+	if (obj || mNegativeCache.isPresent(hash))
 		return obj;
 
 	if (!theApp || !theApp->getHashNodeLDB())
@@ -153,7 +191,7 @@ bool HashedObjectStore::storeSQLite(HashedObjectType type, uint32 index,
 		{
 			mWritePending = true;
 			theApp->getJobQueue().addJob(jtWRITE, "HashedObject::store",
-				BIND_TYPE(&HashedObjectStore::bulkWrite, this));
+				BIND_TYPE(&HashedObjectStore::bulkWriteSQLite, this));
 		}
 	}
 //	else
@@ -172,7 +210,7 @@ void HashedObjectStore::waitWrite()
 		mWriteCondition.wait(sl);
 }
 
-void HashedObjectStore::bulkWrite()
+void HashedObjectStore::bulkWriteSQLite()
 {
 	assert(!mLevelDB);
 	while (1)

src/cpp/ripple/HashedObject.h

@@ -88,14 +88,16 @@ public:
 	bool storeSQLite(HashedObjectType type, uint32 index, const std::vector<unsigned char>& data,
 		const uint256& hash);
 	HashedObject::pointer retrieveSQLite(const uint256& hash);
+	void bulkWriteSQLite();
 
 #ifdef USE_LEVELDB
 	bool storeLevelDB(HashedObjectType type, uint32 index, const std::vector<unsigned char>& data,
 		const uint256& hash);
 	HashedObject::pointer retrieveLevelDB(const uint256& hash);
+	void bulkWriteLevelDB();
 #endif
 
-	void bulkWrite();
+
 	void waitWrite();
 	void tune(int size, int age);
 	void sweep() { mCache.sweep(); mNegativeCache.sweep(); }