rocksdb/util/posix_logger.h
Igor Canadi 444cf88a56 Flush the log outside of lock
Summary:
Added a new call LogFlush() that flushes the log contents to the OS buffers. We never call it with lock held.

We call it once for every Read/Write and often in compaction/flush process so the frequency should not be a problem.

Test Plan: db_test

Reviewers: dhruba, haobo, kailiu, emayanke

Reviewed By: dhruba

CC: leveldb

Differential Revision: https://reviews.facebook.net/D13935
2013-11-07 11:31:56 -08:00

149 lines
4.4 KiB
C++

// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
// 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.
//
// Logger implementation that can be shared by all environments
// where enough posix functionality is available.
#pragma once
#include <algorithm>
#include <stdio.h>
#include <sys/time.h>
#include <time.h>
#include <fcntl.h>
#include <unistd.h>
#ifdef OS_LINUX
#include <linux/falloc.h>
#endif
#include "rocksdb/env.h"
#include <atomic>
namespace rocksdb {
const int kDebugLogChunkSize = 128 * 1024;
class PosixLogger : public Logger {
private:
FILE* file_;
uint64_t (*gettid_)(); // Return the thread id for the current thread
std::atomic_size_t log_size_;
int fd_;
const static uint64_t flush_every_seconds_ = 5;
std::atomic_uint_fast64_t last_flush_micros_;
Env* env_;
public:
PosixLogger(FILE* f, uint64_t (*gettid)(), Env* env) :
file_(f), gettid_(gettid), log_size_(0), fd_(fileno(f)),
last_flush_micros_(0), env_(env) { }
virtual ~PosixLogger() {
fclose(file_);
}
virtual void Flush() {
fflush(file_);
last_flush_micros_ = env_->NowMicros();
}
virtual void Logv(const char* format, va_list ap) {
const uint64_t thread_id = (*gettid_)();
// We try twice: the first time with a fixed-size stack allocated buffer,
// and the second time with a much larger dynamically allocated buffer.
char buffer[500];
for (int iter = 0; iter < 2; iter++) {
char* base;
int bufsize;
if (iter == 0) {
bufsize = sizeof(buffer);
base = buffer;
} else {
bufsize = 30000;
base = new char[bufsize];
}
char* p = base;
char* limit = base + bufsize;
struct timeval now_tv;
gettimeofday(&now_tv, nullptr);
const time_t seconds = now_tv.tv_sec;
struct tm t;
localtime_r(&seconds, &t);
p += snprintf(p, limit - p,
"%04d/%02d/%02d-%02d:%02d:%02d.%06d %llx ",
t.tm_year + 1900,
t.tm_mon + 1,
t.tm_mday,
t.tm_hour,
t.tm_min,
t.tm_sec,
static_cast<int>(now_tv.tv_usec),
static_cast<long long unsigned int>(thread_id));
// Print the message
if (p < limit) {
va_list backup_ap;
va_copy(backup_ap, ap);
p += vsnprintf(p, limit - p, format, backup_ap);
va_end(backup_ap);
}
// Truncate to available space if necessary
if (p >= limit) {
if (iter == 0) {
continue; // Try again with larger buffer
} else {
p = limit - 1;
}
}
// Add newline if necessary
if (p == base || p[-1] != '\n') {
*p++ = '\n';
}
assert(p <= limit);
const size_t write_size = p - base;
#ifdef OS_LINUX
// If this write would cross a boundary of kDebugLogChunkSize
// space, pre-allocate more space to avoid overly large
// allocations from filesystem allocsize options.
const size_t log_size = log_size_;
const int last_allocation_chunk =
((kDebugLogChunkSize - 1 + log_size) / kDebugLogChunkSize);
const int desired_allocation_chunk =
((kDebugLogChunkSize - 1 + log_size + write_size) /
kDebugLogChunkSize);
if (last_allocation_chunk != desired_allocation_chunk) {
fallocate(fd_, FALLOC_FL_KEEP_SIZE, 0,
desired_allocation_chunk * kDebugLogChunkSize);
}
#endif
size_t sz = fwrite(base, 1, write_size, file_);
assert(sz == write_size);
if (sz > 0) {
log_size_ += write_size;
}
uint64_t now_micros = static_cast<uint64_t>(now_tv.tv_sec) * 1000000 +
now_tv.tv_usec;
if (now_micros - last_flush_micros_ >= flush_every_seconds_ * 1000000) {
fflush(file_);
last_flush_micros_ = now_micros;
}
if (base != buffer) {
delete[] base;
}
break;
}
}
size_t GetLogFileSize() const {
return log_size_;
}
};
} // namespace rocksdb