101 lines
4.6 KiB
C++
101 lines
4.6 KiB
C++
/*
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* IKeyValueStore.h
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*
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* This source file is part of the FoundationDB open source project
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*
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* Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef FDBSERVER_IKEYVALUESTORE_H
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#define FDBSERVER_IKEYVALUESTORE_H
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#pragma once
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#include "fdbclient/FDBTypes.h"
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#include "Knobs.h"
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class IClosable {
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public:
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// IClosable is a base interface for any disk-backed data structure that needs to support asynchronous errors, shutdown and deletion
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virtual Future<Void> getError() = 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.
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virtual Future<Void> onClosed() = 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!
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virtual void dispose() = 0; // permanently delete the data AND invalidate this interface
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virtual void close() = 0; // invalidate this interface, but do not delete the data. Outstanding operations may or may not take effect in the background.
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};
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class IKeyValueStore : public IClosable {
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public:
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virtual KeyValueStoreType getType() = 0;
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virtual void set( KeyValueRef keyValue, const Arena* arena = NULL ) = 0;
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virtual void clear( KeyRangeRef range, const Arena* arena = NULL ) = 0;
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virtual Future<Void> commit(bool sequential = false) = 0; // returns when prior sets and clears are (atomically) durable
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virtual Future<Optional<Value>> readValue( KeyRef key, Optional<UID> debugID = Optional<UID>() ) = 0;
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// Like readValue(), but returns only the first maxLength bytes of the value if it is longer
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virtual Future<Optional<Value>> readValuePrefix( KeyRef key, int maxLength, Optional<UID> debugID = Optional<UID>() ) = 0;
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// If rowLimit>=0, reads first rows sorted ascending, otherwise reads last rows sorted descending
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// The total size of the returned value (less the last entry) will be less than byteLimit
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virtual Future<Standalone<VectorRef<KeyValueRef>>> readRange( KeyRangeRef keys, int rowLimit = 1<<30, int byteLimit = 1<<30 ) = 0;
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//Returns the amount of free and total space for this store, in bytes
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virtual StorageBytes getStorageBytes() = 0;
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virtual void resyncLog() {}
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virtual void enableSnapshot() {}
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/*
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Concurrency contract
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Causal consistency:
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A read which begins after a commit ends sees the effects of the commit.
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A read which ends before a commit begins does not see the effects of the commit.
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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:
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commit() // can't be this version (subsequent commit ends before read begins)
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endcommit()
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commit() // could be this or any later version (no subsequent commit ends before read begins)
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endcommit()
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commit()
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read()
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*/
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protected:
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virtual ~IKeyValueStore() {}
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};
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extern IKeyValueStore* keyValueStoreSQLite( std::string const& filename, UID logID, KeyValueStoreType storeType, bool checkChecksums=false, bool checkIntegrity=false );
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extern IKeyValueStore* keyValueStoreMemory( std::string const& basename, UID logID, int64_t memoryLimit );
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extern IKeyValueStore* keyValueStoreLogSystem( class IDiskQueue* queue, UID logID, int64_t memoryLimit, bool disableSnapshot, bool replaceContent, bool exactRecovery );
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inline IKeyValueStore* openKVStore( KeyValueStoreType storeType, std::string const& filename, UID logID, int64_t memoryLimit, bool checkChecksums=false, bool checkIntegrity=false ) {
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switch( storeType ) {
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case KeyValueStoreType::SSD_BTREE_V1:
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return keyValueStoreSQLite(filename, logID, KeyValueStoreType::SSD_BTREE_V1, false, checkIntegrity);
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case KeyValueStoreType::SSD_BTREE_V2:
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return keyValueStoreSQLite(filename, logID, KeyValueStoreType::SSD_BTREE_V2, checkChecksums, checkIntegrity);
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case KeyValueStoreType::MEMORY:
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return keyValueStoreMemory( filename, logID, memoryLimit );
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default:
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UNREACHABLE();
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}
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UNREACHABLE(); // FIXME: is this right?
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}
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void GenerateIOLogChecksumFile(std::string filename);
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Future<Void> KVFileCheck(std::string const & filename, bool const &integrity);
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#endif
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