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arangodb/arangod/StorageEngine/OtherEngine.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_OTHER_ENGINE_H
#define ARANGOD_STORAGE_ENGINE_OTHER_ENGINE_H 1
#include "Basics/Common.h"
#include "StorageEngine/StorageEngine.h"
namespace arangodb {
class OtherEngine final : public StorageEngine {
public:
// create the storage engine
explicit OtherEngine(application_features::ApplicationServer*);
~OtherEngine();
// 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;
// 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 only
int getCollectionsAndIndexes(TRI_vocbase_t* vocbase, arangodb::velocypack::Builder& result, bool, bool) override;
// determine the maximum revision id previously handed out by the storage
// engine. this value is used as a lower bound for further HLC values handed out by
// the server. called at server start only, after getDatabases() and getCollectionsAndIndexes()
uint64_t getMaxRevision() override;
// return the path for a database
std::string databasePath(TRI_vocbase_t const*) const override { return "none"; }
// return the path for a collection
std::string collectionPath(TRI_vocbase_t const*, TRI_voc_cid_t) const override { return "none"; }
TRI_vocbase_t* openDatabase(arangodb::velocypack::Slice const& parameters, bool isUpgrade) override {
return nullptr;
}
// 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 remove data of expired compaction blockers
bool cleanupCompactionBlockers(TRI_vocbase_t* vocbase) override { return false; }
/// @brief insert a compaction blocker
int insertCompactionBlocker(TRI_vocbase_t* vocbase, double ttl, TRI_voc_tick_t& id) override {
id = 0;
return TRI_ERROR_NO_ERROR;
}
/// @brief touch an existing compaction blocker
int extendCompactionBlocker(TRI_vocbase_t* vocbase, TRI_voc_tick_t id, double ttl) override {
return TRI_ERROR_NO_ERROR;
}
/// @brief remove an existing compaction blocker
int removeCompactionBlocker(TRI_vocbase_t* vocbase, TRI_voc_tick_t id) override {
return TRI_ERROR_NO_ERROR;
}
/// @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 {
return true;
}
int shutdownDatabase(TRI_vocbase_t* vocbase) override {
return TRI_ERROR_NO_ERROR;
}
int openCollection(TRI_vocbase_t* vocbase, LogicalCollection* collection, bool ignoreErrors) override {
return TRI_ERROR_NO_ERROR;
}
/// @brief transfer markers into a collection
int transferMarkers(LogicalCollection* collection, wal::CollectorCache*,
wal::OperationsType const&) override {
return TRI_ERROR_NO_ERROR;
}
public:
static std::string const EngineName;
};
}
#endif