foundationdb/fdbserver/IKeyValueStore.h

207 lines
9.2 KiB
C++

/*
* IKeyValueStore.h
*
* This source file is part of the FoundationDB open source project
*
* Copyright 2013-2022 Apple Inc. and the FoundationDB project authors
*
* 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.
*/
#ifndef FDBSERVER_IKEYVALUESTORE_H
#define FDBSERVER_IKEYVALUESTORE_H
#pragma once
#include "fdbclient/FDBTypes.h"
#include "fdbserver/Knobs.h"
#include "fdbclient/StorageCheckpoint.h"
struct CheckpointRequest {
const Version version; // The FDB version at which the checkpoint is created.
const KeyRange range; // Keyrange this checkpoint must contain.
const CheckpointFormat format;
const UID checkpointID;
const std::string checkpointDir; // The local directory where the checkpoint file will be created.
CheckpointRequest(const Version version,
const KeyRange& range,
const CheckpointFormat format,
const UID& id,
const std::string& checkpointDir)
: version(version), range(range), format(format), checkpointID(id), checkpointDir(checkpointDir) {}
};
class IClosable {
public:
// IClosable is a base interface for any disk-backed data structure that needs to support asynchronous errors,
// shutdown and deletion
virtual Future<Void> getError()
const = 0; // asynchronously throws an error if there is an internal error. Never set
// inside (on the stack of) a call to another API function on this object.
virtual Future<Void> onClosed()
const = 0; // the future is set to Void when this is totally shut down after dispose() or
// close(). But this function cannot be called after dispose or close!
virtual void dispose() = 0; // permanently delete the data AND invalidate this interface
virtual void close() = 0; // invalidate this interface, but do not delete the data. Outstanding operations may or
// may not take effect in the background.
};
class IKeyValueStore : public IClosable {
public:
virtual KeyValueStoreType getType() const = 0;
virtual void set(KeyValueRef keyValue, const Arena* arena = nullptr) = 0;
virtual void clear(KeyRangeRef range, const Arena* arena = nullptr) = 0;
virtual Future<Void> canCommit() { return Void(); }
virtual Future<Void> commit(
bool sequential = false) = 0; // returns when prior sets and clears are (atomically) durable
enum class ReadType {
EAGER,
FETCH,
LOW,
NORMAL,
HIGH,
};
virtual Future<Optional<Value>> readValue(KeyRef key,
ReadType type = ReadType::NORMAL,
Optional<UID> debugID = Optional<UID>()) = 0;
// Like readValue(), but returns only the first maxLength bytes of the value if it is longer
virtual Future<Optional<Value>> readValuePrefix(KeyRef key,
int maxLength,
ReadType type = ReadType::NORMAL,
Optional<UID> debugID = Optional<UID>()) = 0;
// If rowLimit>=0, reads first rows sorted ascending, otherwise reads last rows sorted descending
// The total size of the returned value (less the last entry) will be less than byteLimit
virtual Future<RangeResult> readRange(KeyRangeRef keys,
int rowLimit = 1 << 30,
int byteLimit = 1 << 30,
ReadType type = ReadType::NORMAL) = 0;
// To debug MEMORY_RADIXTREE type ONLY
// Returns (1) how many key & value pairs have been inserted (2) how many nodes have been created (3) how many
// key size is less than 12 bytes
virtual std::tuple<size_t, size_t, size_t> getSize() const { return std::make_tuple(0, 0, 0); }
// Returns the amount of free and total space for this store, in bytes
virtual StorageBytes getStorageBytes() const = 0;
virtual void resyncLog() {}
virtual void enableSnapshot() {}
// Create a checkpoint.
virtual Future<CheckpointMetaData> checkpoint(const CheckpointRequest& request) { throw not_implemented(); }
// Restore from a checkpoint.
virtual Future<Void> restore(const std::vector<CheckpointMetaData>& checkpoints) { throw not_implemented(); }
// Delete a checkpoint.
virtual Future<Void> deleteCheckpoint(const CheckpointMetaData& checkpoint) { throw not_implemented(); }
/*
Concurrency contract
Causal consistency:
A read which begins after a commit ends sees the effects of the commit.
A read which ends before a commit begins does not see the effects of the commit.
Thus, a read returns a version as of a call to commit which began before the read ends such that no subsequent
commit ended before the read begins:
commit() // can't be this version (subsequent commit ends before read begins)
endcommit()
commit() // could be this or any later version (no subsequent commit ends before read begins)
endcommit()
commit()
read()
*/
// `init()` MUST be idempotent as it will be called more than once on a KeyValueStore in case
// of a rollback.
virtual Future<Void> init() { return Void(); }
protected:
virtual ~IKeyValueStore() {}
};
extern IKeyValueStore* keyValueStoreSQLite(std::string const& filename,
UID logID,
KeyValueStoreType storeType,
bool checkChecksums = false,
bool checkIntegrity = false);
extern IKeyValueStore* keyValueStoreRedwoodV1(std::string const& filename, UID logID);
extern IKeyValueStore* keyValueStoreRocksDB(std::string const& path,
UID logID,
KeyValueStoreType storeType,
bool checkChecksums = false,
bool checkIntegrity = false);
extern IKeyValueStore* keyValueStoreMemory(std::string const& basename,
UID logID,
int64_t memoryLimit,
std::string ext = "fdq",
KeyValueStoreType storeType = KeyValueStoreType::MEMORY);
extern IKeyValueStore* keyValueStoreLogSystem(class IDiskQueue* queue,
UID logID,
int64_t memoryLimit,
bool disableSnapshot,
bool replaceContent,
bool exactRecovery);
extern IKeyValueStore* openRemoteKVStore(KeyValueStoreType storeType,
std::string const& filename,
UID logID,
int64_t memoryLimit,
bool checkChecksums = false,
bool checkIntegrity = false);
inline IKeyValueStore* openKVStore(KeyValueStoreType storeType,
std::string const& filename,
UID logID,
int64_t memoryLimit,
bool checkChecksums = false,
bool checkIntegrity = false,
bool openRemotely = false) {
if (openRemotely) {
return openRemoteKVStore(storeType, filename, logID, memoryLimit, checkChecksums, checkIntegrity);
}
switch (storeType) {
case KeyValueStoreType::SSD_BTREE_V1:
return keyValueStoreSQLite(filename, logID, KeyValueStoreType::SSD_BTREE_V1, false, checkIntegrity);
case KeyValueStoreType::SSD_BTREE_V2:
return keyValueStoreSQLite(filename, logID, KeyValueStoreType::SSD_BTREE_V2, checkChecksums, checkIntegrity);
case KeyValueStoreType::MEMORY:
return keyValueStoreMemory(filename, logID, memoryLimit);
case KeyValueStoreType::SSD_REDWOOD_V1:
return keyValueStoreRedwoodV1(filename, logID);
case KeyValueStoreType::SSD_ROCKSDB_V1:
return keyValueStoreRocksDB(filename, logID, storeType);
case KeyValueStoreType::MEMORY_RADIXTREE:
return keyValueStoreMemory(filename,
logID,
memoryLimit,
"fdr",
KeyValueStoreType::MEMORY_RADIXTREE); // for radixTree type, set file ext to "fdr"
default:
UNREACHABLE();
}
UNREACHABLE(); // FIXME: is this right?
}
void GenerateIOLogChecksumFile(std::string filename);
Future<Void> KVFileCheck(std::string const& filename, bool const& integrity);
Future<Void> KVFileDump(std::string const& filename);
#endif