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fe25070242
Summary: Currently for each put, a fresh memory is allocated, and a new entry is added to the memtable with a new sequence number irrespective of whether the key already exists in the memtable. This diff is an attempt to update the value inplace for existing keys. It currently handles a very simple case: 1. Key already exists in the current memtable. Does not inplace update values in immutable memtable or snapshot 2. Latest value type is a 'put' ie kTypeValue 3. New value size is less than existing value, to avoid reallocating memory TODO: For a put of an existing key, deallocate memory take by values, for other value types till a kTypeValue is found, ie. remove kTypeMerge. TODO: Update the transaction log, to allow consistent reload of the memtable. Test Plan: Added a unit test verifying the inplace update. But some other unit tests broken due to invalid sequence number checks. WIll fix them next. Reviewers: xinyaohu, sumeet, haobo, dhruba CC: leveldb Differential Revision: https://reviews.facebook.net/D12423 Automatic commit by arc
58 lines
2 KiB
C++
58 lines
2 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include "rocksdb/types.h"
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#include "rocksdb/write_batch.h"
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#include "rocksdb/db.h"
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#include "rocksdb/options.h"
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namespace rocksdb {
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class MemTable;
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// WriteBatchInternal provides static methods for manipulating a
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// WriteBatch that we don't want in the public WriteBatch interface.
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class WriteBatchInternal {
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public:
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// Return the number of entries in the batch.
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static int Count(const WriteBatch* batch);
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// Set the count for the number of entries in the batch.
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static void SetCount(WriteBatch* batch, int n);
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// Return the seqeunce number for the start of this batch.
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static SequenceNumber Sequence(const WriteBatch* batch);
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// Store the specified number as the seqeunce number for the start of
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// this batch.
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static void SetSequence(WriteBatch* batch, SequenceNumber seq);
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static Slice Contents(const WriteBatch* batch) {
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return Slice(batch->rep_);
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}
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static size_t ByteSize(const WriteBatch* batch) {
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return batch->rep_.size();
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}
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static void SetContents(WriteBatch* batch, const Slice& contents);
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// Inserts batch entries into memtable
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// Drops deletes in batch if filter_del is set to true and
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// db->KeyMayExist returns false
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static Status InsertInto(const WriteBatch* batch, MemTable* memtable,
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const Options* opts, DB* db = nullptr,
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const bool filter_del = false);
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static void Append(WriteBatch* dst, const WriteBatch* src);
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};
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} // namespace rocksdb
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