Revision 33323f21117e5bb8cf72569302f109aabb387bb9 authored by Mark Callaghan on 14 September 2012, 19:35:02 UTC, committed by Mark Callaghan on 14 September 2012, 23:43:50 UTC
Summary: Reads via mmap on concurrent workloads are much slower than pread. For example on a 24-core server with storage that can do 100k IOPS or more I can get no more than 10k IOPS with mmap reads and 32+ threads. Test Plan: db_bench benchmarks Reviewers: dhruba, heyongqiang Reviewed By: heyongqiang Differential Revision: https://reviews.facebook.net/D5433
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write_batch_internal.h
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_DB_WRITE_BATCH_INTERNAL_H_
#define STORAGE_LEVELDB_DB_WRITE_BATCH_INTERNAL_H_
#include "leveldb/write_batch.h"
namespace leveldb {
class MemTable;
// WriteBatchInternal provides static methods for manipulating a
// WriteBatch that we don't want in the public WriteBatch interface.
class WriteBatchInternal {
public:
// Return the number of entries in the batch.
static int Count(const WriteBatch* batch);
// Set the count for the number of entries in the batch.
static void SetCount(WriteBatch* batch, int n);
// Return the seqeunce number for the start of this batch.
static SequenceNumber Sequence(const WriteBatch* batch);
// Store the specified number as the seqeunce number for the start of
// this batch.
static void SetSequence(WriteBatch* batch, SequenceNumber seq);
static Slice Contents(const WriteBatch* batch) {
return Slice(batch->rep_);
}
static size_t ByteSize(const WriteBatch* batch) {
return batch->rep_.size();
}
static void SetContents(WriteBatch* batch, const Slice& contents);
static Status InsertInto(const WriteBatch* batch, MemTable* memtable);
static void Append(WriteBatch* dst, const WriteBatch* src);
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_DB_WRITE_BATCH_INTERNAL_H_
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