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arangodb/arangod/StorageEngine/MMFilesEngine.h

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////////////////////////////////////////////////////////////////////////////////
/// DISCLAIMER
///
/// Copyright 2014-2016 ArangoDB GmbH, Cologne, Germany
/// Copyright 2004-2014 triAGENS GmbH, Cologne, Germany
///
/// Licensed under the Apache License, Version 2.0 (the "License");
/// you may not use this file except in compliance with the License.
/// You may obtain a copy of the License at
///
/// http://www.apache.org/licenses/LICENSE-2.0
///
/// Unless required by applicable law or agreed to in writing, software
/// distributed under the License is distributed on an "AS IS" BASIS,
/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
/// See the License for the specific language governing permissions and
/// limitations under the License.
///
/// Copyright holder is ArangoDB GmbH, Cologne, Germany
///
/// @author Jan Steemann
////////////////////////////////////////////////////////////////////////////////
#ifndef ARANGOD_STORAGE_ENGINE_MMFILES_ENGINE_H
#define ARANGOD_STORAGE_ENGINE_MMFILES_ENGINE_H 1
#include "Basics/Common.h"
#include "Basics/Mutex.h"
#include "StorageEngine/StorageEngine.h"
#include <velocypack/Builder.h>
namespace arangodb {
class MMFilesCleanupThread;
class MMFilesCompactorThread;
/// @brief collection file structure
struct MMFilesEngineCollectionFiles {
std::vector<std::string> journals;
std::vector<std::string> compactors;
std::vector<std::string> datafiles;
std::vector<std::string> indexes;
};
class MMFilesEngine final : public StorageEngine {
public:
// create the storage engine
explicit MMFilesEngine(application_features::ApplicationServer*);
~MMFilesEngine();
// inherited from ApplicationFeature
// ---------------------------------
// add the storage engine's specifc options to the global list of options
void collectOptions(std::shared_ptr<options::ProgramOptions>) override;
// validate the storage engine's specific options
void validateOptions(std::shared_ptr<options::ProgramOptions>) override;
// preparation phase for storage engine. can be used for internal setup.
// the storage engine must not start any threads here or write any files
void prepare() override;
// initialize engine
void start() override;
void stop() override;
// called when recovery is finished
void recoveryDone(TRI_vocbase_t* vocbase) override;
// create storage-engine specific collection
PhysicalCollection* createPhysicalCollection(LogicalCollection*) override;
// inventory functionality
// -----------------------
// fill the Builder object with an array of databases that were detected
// by the storage engine. this method must sort out databases that were not
// fully created (see "createDatabase" below). called at server start only
void getDatabases(arangodb::velocypack::Builder& result) override;
// fills the provided builder with information about the collection
void getCollectionInfo(TRI_vocbase_t* vocbase, TRI_voc_cid_t cid,
arangodb::velocypack::Builder& result,
bool includeIndexes, TRI_voc_tick_t maxTick) override;
// fill the Builder object with an array of collections (and their corresponding
// indexes) that were detected by the storage engine. called at server start separately
// for each database
int getCollectionsAndIndexes(TRI_vocbase_t* vocbase, arangodb::velocypack::Builder& result,
bool wasCleanShutdown, bool isUpgrade) override;
// return the path for a database
std::string databasePath(TRI_vocbase_t const* vocbase) const override {
return databaseDirectory(vocbase->id());
}
// return the path for a collection
std::string collectionPath(TRI_vocbase_t const* vocbase, TRI_voc_cid_t id) const override {
return collectionDirectory(vocbase->id(), id);
}
TRI_vocbase_t* openDatabase(arangodb::velocypack::Slice const& parameters, bool isUpgrade) override;
// database, collection and index management
// -----------------------------------------
// asks the storage engine to create a database as specified in the VPack
// Slice object and persist the creation info. It is guaranteed by the server that
// no other active database with the same name and id exists when this function
// is called. If this operation fails somewhere in the middle, the storage
// engine is required to fully clean up the creation and throw only then,
// so that subsequent database creation requests will not fail.
// the WAL entry for the database creation will be written *after* the call
// to "createDatabase" returns
TRI_vocbase_t* createDatabase(TRI_voc_tick_t id, arangodb::velocypack::Slice const& data) override;
// asks the storage engine to drop the specified database and persist the
// deletion info. Note that physical deletion of the database data must not
// be carried out by this call, as there may still be readers of the database's data.
// It is recommended that this operation only sets a deletion flag for the database
// but let's an async task perform the actual deletion.
// the WAL entry for database deletion will be written *after* the call
// to "prepareDropDatabase" returns
int prepareDropDatabase(TRI_vocbase_t* vocbase) override;
// perform a physical deletion of the database
int dropDatabase(TRI_vocbase_t* vocbase) override;
/// @brief wait until a database directory disappears
int waitUntilDeletion(TRI_voc_tick_t id, bool force) override;
// asks the storage engine to create a collection as specified in the VPack
// Slice object and persist the creation info. It is guaranteed by the server
// that no other active collection with the same name and id exists in the same
// database when this function is called. If this operation fails somewhere in
// the middle, the storage engine is required to fully clean up the creation
// and throw only then, so that subsequent collection creation requests will not fail.
// the WAL entry for the collection creation will be written *after* the call
// to "createCollection" returns
std::string createCollection(TRI_vocbase_t* vocbase, TRI_voc_cid_t id,
arangodb::LogicalCollection const* parameters) override;
// asks the storage engine to drop the specified collection and persist the
// deletion info. Note that physical deletion of the collection data must not
// be carried out by this call, as there may
// still be readers of the collection's data. It is recommended that this operation
// only sets a deletion flag for the collection but let's an async task perform
// the actual deletion.
// the WAL entry for collection deletion will be written *after* the call
// to "dropCollection" returns
void prepareDropCollection(TRI_vocbase_t* vocbase, arangodb::LogicalCollection* collection) override;
// perform a physical deletion of the collection
void dropCollection(TRI_vocbase_t* vocbase, arangodb::LogicalCollection* collection) override;
// asks the storage engine to change properties of the collection as specified in
// the VPack Slice object and persist them. If this operation fails
// somewhere in the middle, the storage engine is required to fully revert the
// property changes and throw only then, so that subsequent operations will not fail.
// the WAL entry for the propery change will be written *after* the call
// to "changeCollection" returns
void changeCollection(TRI_vocbase_t* vocbase, TRI_voc_cid_t id,
arangodb::LogicalCollection const* parameters,
bool doSync) override;
// asks the storage engine to create an index as specified in the VPack
// Slice object and persist the creation info. The database id, collection id
// and index data are passed in the Slice object. Note that this function
// is not responsible for inserting the individual documents into the index.
// If this operation fails somewhere in the middle, the storage engine is required
// to fully clean up the creation and throw only then, so that subsequent index
// creation requests will not fail.
// the WAL entry for the index creation will be written *after* the call
// to "createIndex" returns
void createIndex(TRI_vocbase_t* vocbase, TRI_voc_cid_t collectionId,
TRI_idx_iid_t id, arangodb::velocypack::Slice const& data) override;
// asks the storage engine to drop the specified index and persist the deletion
// info. Note that physical deletion of the index must not be carried out by this call,
// as there may still be users of the index. It is recommended that this operation
// only sets a deletion flag for the index but let's an async task perform
// the actual deletion.
// the WAL entry for index deletion will be written *after* the call
// to "dropIndex" returns
void dropIndex(TRI_vocbase_t* vocbase, TRI_voc_cid_t collectionId,
TRI_idx_iid_t id) override;
void unloadCollection(TRI_vocbase_t* vocbase, TRI_voc_cid_t collectionId) override;
void signalCleanup(TRI_vocbase_t* vocbase) override;
// document operations
// -------------------
// iterate all documents of the underlying collection
// this is called when a collection is openend, and all its documents need to be added to
// indexes etc.
void iterateDocuments(TRI_voc_tick_t databaseId, TRI_voc_cid_t collectionId,
std::function<void(arangodb::velocypack::Slice const&)> const& cb) override;
// adds a document to the storage engine
// this will be called by the WAL collector when surviving documents are being moved
// into the storage engine's realm
void addDocumentRevision(TRI_voc_tick_t databaseId, TRI_voc_cid_t collectionId,
arangodb::velocypack::Slice const& document) override;
// removes a document from the storage engine
// this will be called by the WAL collector when non-surviving documents are being removed
// from the storage engine's realm
void removeDocumentRevision(TRI_voc_tick_t databaseId, TRI_voc_cid_t collectionId,
arangodb::velocypack::Slice const& document) override;
/// @brief scans a collection and locates all files
MMFilesEngineCollectionFiles scanCollectionDirectory(std::string const& path);
/// @brief remove data of expired compaction blockers
bool cleanupCompactionBlockers(TRI_vocbase_t* vocbase) override;
/// @brief insert a compaction blocker
int insertCompactionBlocker(TRI_vocbase_t* vocbase, double ttl, TRI_voc_tick_t& id) override;
/// @brief touch an existing compaction blocker
int extendCompactionBlocker(TRI_vocbase_t* vocbase, TRI_voc_tick_t id, double ttl) override;
/// @brief remove an existing compaction blocker
int removeCompactionBlocker(TRI_vocbase_t* vocbase, TRI_voc_tick_t id) override;
/// @brief a callback function that is run while it is guaranteed that there is no compaction ongoing
void preventCompaction(TRI_vocbase_t* vocbase,
std::function<void(TRI_vocbase_t*)> const& callback) override;
/// @brief a callback function that is run there is no compaction ongoing
bool tryPreventCompaction(TRI_vocbase_t* vocbase,
std::function<void(TRI_vocbase_t*)> const& callback,
bool checkForActiveBlockers) override;
int shutdownDatabase(TRI_vocbase_t* vocbase) override;
int openCollection(TRI_vocbase_t* vocbase, LogicalCollection* collection, bool ignoreErrors) override;
/// @brief transfer markers into a collection
int transferMarkers(LogicalCollection* collection, wal::CollectorCache*,
wal::OperationsType const&) override;
private:
/// @brief: check the initial markers in a datafile
bool checkDatafileHeader(TRI_datafile_t* datafile, std::string const& filename) const;
/// @brief transfer markers into a collection, worker function
int transferMarkersWorker(LogicalCollection* collection, wal::CollectorCache*,
wal::OperationsType const&);
/// @brief sync the active journal of a collection
int syncJournalCollection(LogicalCollection* collection);
/// @brief get the next free position for a new marker of the specified size
char* nextFreeMarkerPosition(LogicalCollection* collection,
TRI_voc_tick_t, TRI_df_marker_type_t,
TRI_voc_size_t, wal::CollectorCache*);
/// @brief set the tick of a marker and calculate its CRC value
void finishMarker(char const*, char*, LogicalCollection* collection,
TRI_voc_tick_t, wal::CollectorCache*);
void verifyDirectories();
std::vector<std::string> getDatabaseNames() const;
/// @brief create a new database directory
int createDatabaseDirectory(TRI_voc_tick_t id, std::string const& name);
/// @brief save a parameter.json file for a database
int saveDatabaseParameters(TRI_voc_tick_t id, std::string const& name, bool deleted);
arangodb::velocypack::Builder databaseToVelocyPack(TRI_voc_tick_t databaseId,
std::string const& name,
bool deleted) const;
std::string databaseDirectory(TRI_voc_tick_t databaseId) const;
std::string databaseParametersFilename(TRI_voc_tick_t databaseId) const;
std::string collectionDirectory(TRI_voc_tick_t databaseId, TRI_voc_cid_t collectionId) const;
std::string collectionParametersFilename(TRI_voc_tick_t databaseId, TRI_voc_cid_t collectionId) const;
std::string indexFilename(TRI_voc_tick_t databaseId, TRI_voc_cid_t collectionId, TRI_idx_iid_t indexId) const;
std::string indexFilename(TRI_idx_iid_t indexId) const;
int openDatabases();
/// @brief open an existing database. internal function
TRI_vocbase_t* openExistingDatabase(TRI_voc_tick_t id, std::string const& name, bool wasCleanShutdown, bool isUpgrade);
/// @brief note the maximum local tick
void noteTick(TRI_voc_tick_t tick) {
if (tick > _maxTick) { _maxTick = tick; }
}
/// @brief physically erases the database directory
int dropDatabaseDirectory(std::string const& path);
/// @brief iterate over a set of datafiles, identified by filenames
/// note: the files will be opened and closed
bool iterateFiles(std::vector<std::string> const& files);
/// @brief find the maximum tick in a collection's journals
bool findMaxTickInJournals(std::string const& path);
/// @brief create a full directory name for a collection
std::string createCollectionDirectoryName(std::string const& basePath, TRI_voc_cid_t cid);
void registerCollectionPath(TRI_voc_tick_t databaseId, TRI_voc_cid_t id, std::string const& path);
void unregisterCollectionPath(TRI_voc_tick_t databaseId, TRI_voc_cid_t id);
void saveCollectionInfo(TRI_vocbase_t* vocbase,
TRI_voc_cid_t id,
arangodb::LogicalCollection const* parameters,
bool forceSync) const;
LogicalCollection* loadCollectionInfo(TRI_vocbase_t* vocbase, std::string const& path);
// start the cleanup thread for the database
int startCleanup(TRI_vocbase_t* vocbase);
// stop and delete the cleanup thread for the database
int stopCleanup(TRI_vocbase_t* vocbase);
// start the compactor thread for the database
int startCompactor(TRI_vocbase_t* vocbase);
// signal the compactor thread to stop
int beginShutdownCompactor(TRI_vocbase_t* vocbase);
// stop and delete the compactor thread for the database
int stopCompactor(TRI_vocbase_t* vocbase);
public:
static std::string const EngineName;
static std::string const FeatureName;
private:
std::string _basePath;
std::string _databasePath;
bool _isUpgrade;
TRI_voc_tick_t _maxTick;
std::vector<std::pair<std::string, std::string>> _deleted;
arangodb::basics::ReadWriteLock mutable _pathsLock;
std::unordered_map<TRI_voc_tick_t, std::unordered_map<TRI_voc_cid_t, std::string>> _collectionPaths;
struct CompactionBlocker {
CompactionBlocker(TRI_voc_tick_t id, double expires) : _id(id), _expires(expires) {}
CompactionBlocker() = delete;
TRI_voc_tick_t _id;
double _expires;
};
// lock for compaction blockers
arangodb::basics::ReadWriteLock mutable _compactionBlockersLock;
// cross-database map of compaction blockers, protected by _compactionBlockersLock
std::unordered_map<TRI_vocbase_t*, std::vector<CompactionBlocker>> _compactionBlockers;
// lock for threads
arangodb::Mutex _threadsLock;
// per-database compactor threads, protected by _threadsLock
std::unordered_map<TRI_vocbase_t*, MMFilesCompactorThread*> _compactorThreads;
// per-database cleanup threads, protected by _threadsLock
std::unordered_map<TRI_vocbase_t*, MMFilesCleanupThread*> _cleanupThreads;
};
}
#endif