summaryrefslogtreecommitdiffstats
path: root/src/rocksdb/db/wal_manager.cc
blob: a6060235f216bfae4aff7b2593f5dfad04d90d53 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
//  This source code is licensed under both the GPLv2 (found in the
//  COPYING file in the root directory) and Apache 2.0 License
//  (found in the LICENSE.Apache file in the root 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.

#include "db/wal_manager.h"

#include <algorithm>
#include <cinttypes>
#include <memory>
#include <vector>

#include "db/log_reader.h"
#include "db/log_writer.h"
#include "db/transaction_log_impl.h"
#include "db/write_batch_internal.h"
#include "file/file_util.h"
#include "file/filename.h"
#include "file/sequence_file_reader.h"
#include "logging/logging.h"
#include "port/port.h"
#include "rocksdb/env.h"
#include "rocksdb/options.h"
#include "rocksdb/write_batch.h"
#include "test_util/sync_point.h"
#include "util/cast_util.h"
#include "util/coding.h"
#include "util/mutexlock.h"
#include "util/string_util.h"

namespace ROCKSDB_NAMESPACE {

#ifndef ROCKSDB_LITE

Status WalManager::DeleteFile(const std::string& fname, uint64_t number) {
  auto s = env_->DeleteFile(wal_dir_ + "/" + fname);
  if (s.ok()) {
    MutexLock l(&read_first_record_cache_mutex_);
    read_first_record_cache_.erase(number);
  }
  return s;
}

Status WalManager::GetSortedWalFiles(VectorLogPtr& files) {
  // First get sorted files in db dir, then get sorted files from archived
  // dir, to avoid a race condition where a log file is moved to archived
  // dir in between.
  Status s;
  // list wal files in main db dir.
  VectorLogPtr logs;
  s = GetSortedWalsOfType(wal_dir_, logs, kAliveLogFile);
  if (!s.ok()) {
    return s;
  }

  // Reproduce the race condition where a log file is moved
  // to archived dir, between these two sync points, used in
  // (DBTest,TransactionLogIteratorRace)
  TEST_SYNC_POINT("WalManager::GetSortedWalFiles:1");
  TEST_SYNC_POINT("WalManager::GetSortedWalFiles:2");

  files.clear();
  // list wal files in archive dir.
  std::string archivedir = ArchivalDirectory(wal_dir_);
  Status exists = env_->FileExists(archivedir);
  if (exists.ok()) {
    s = GetSortedWalsOfType(archivedir, files, kArchivedLogFile);
    if (!s.ok()) {
      return s;
    }
  } else if (!exists.IsNotFound()) {
    assert(s.IsIOError());
    return s;
  }

  uint64_t latest_archived_log_number = 0;
  if (!files.empty()) {
    latest_archived_log_number = files.back()->LogNumber();
    ROCKS_LOG_INFO(db_options_.info_log, "Latest Archived log: %" PRIu64,
                   latest_archived_log_number);
  }

  files.reserve(files.size() + logs.size());
  for (auto& log : logs) {
    if (log->LogNumber() > latest_archived_log_number) {
      files.push_back(std::move(log));
    } else {
      // When the race condition happens, we could see the
      // same log in both db dir and archived dir. Simply
      // ignore the one in db dir. Note that, if we read
      // archived dir first, we would have missed the log file.
      ROCKS_LOG_WARN(db_options_.info_log, "%s already moved to archive",
                     log->PathName().c_str());
    }
  }

  return s;
}

Status WalManager::GetUpdatesSince(
    SequenceNumber seq, std::unique_ptr<TransactionLogIterator>* iter,
    const TransactionLogIterator::ReadOptions& read_options,
    VersionSet* version_set) {
  if (seq_per_batch_) {
    return Status::NotSupported();
  }

  assert(!seq_per_batch_);

  //  Get all sorted Wal Files.
  //  Do binary search and open files and find the seq number.

  std::unique_ptr<VectorLogPtr> wal_files(new VectorLogPtr);
  Status s = GetSortedWalFiles(*wal_files);
  if (!s.ok()) {
    return s;
  }

  s = RetainProbableWalFiles(*wal_files, seq);
  if (!s.ok()) {
    return s;
  }
  iter->reset(new TransactionLogIteratorImpl(
      wal_dir_, &db_options_, read_options, file_options_, seq,
      std::move(wal_files), version_set, seq_per_batch_, io_tracer_));
  return (*iter)->status();
}

// 1. Go through all archived files and
//    a. if ttl is enabled, delete outdated files
//    b. if archive size limit is enabled, delete empty files,
//        compute file number and size.
// 2. If size limit is enabled:
//    a. compute how many files should be deleted
//    b. get sorted non-empty archived logs
//    c. delete what should be deleted
void WalManager::PurgeObsoleteWALFiles() {
  bool const ttl_enabled = db_options_.WAL_ttl_seconds > 0;
  bool const size_limit_enabled = db_options_.WAL_size_limit_MB > 0;
  if (!ttl_enabled && !size_limit_enabled) {
    return;
  }

  int64_t current_time = 0;
  Status s = db_options_.clock->GetCurrentTime(&current_time);
  if (!s.ok()) {
    ROCKS_LOG_ERROR(db_options_.info_log, "Can't get current time: %s",
                    s.ToString().c_str());
    assert(false);
    return;
  }
  uint64_t const now_seconds = static_cast<uint64_t>(current_time);
  uint64_t const time_to_check = (ttl_enabled && !size_limit_enabled)
                                     ? db_options_.WAL_ttl_seconds / 2
                                     : kDefaultIntervalToDeleteObsoleteWAL;

  if (purge_wal_files_last_run_ + time_to_check > now_seconds) {
    return;
  }

  purge_wal_files_last_run_ = now_seconds;

  std::string archival_dir = ArchivalDirectory(wal_dir_);
  std::vector<std::string> files;
  s = env_->GetChildren(archival_dir, &files);
  if (!s.ok()) {
    ROCKS_LOG_ERROR(db_options_.info_log, "Can't get archive files: %s",
                    s.ToString().c_str());
    assert(false);
    return;
  }

  size_t log_files_num = 0;
  uint64_t log_file_size = 0;
  for (auto& f : files) {
    uint64_t number;
    FileType type;
    if (ParseFileName(f, &number, &type) && type == kWalFile) {
      std::string const file_path = archival_dir + "/" + f;
      if (ttl_enabled) {
        uint64_t file_m_time;
        s = env_->GetFileModificationTime(file_path, &file_m_time);
        if (!s.ok()) {
          ROCKS_LOG_WARN(db_options_.info_log,
                         "Can't get file mod time: %s: %s", file_path.c_str(),
                         s.ToString().c_str());
          continue;
        }
        if (now_seconds - file_m_time > db_options_.WAL_ttl_seconds) {
          s = DeleteDBFile(&db_options_, file_path, archival_dir, false,
                           /*force_fg=*/!wal_in_db_path_);
          if (!s.ok()) {
            ROCKS_LOG_WARN(db_options_.info_log, "Can't delete file: %s: %s",
                           file_path.c_str(), s.ToString().c_str());
            continue;
          } else {
            MutexLock l(&read_first_record_cache_mutex_);
            read_first_record_cache_.erase(number);
          }
          continue;
        }
      }

      if (size_limit_enabled) {
        uint64_t file_size;
        s = env_->GetFileSize(file_path, &file_size);
        if (!s.ok()) {
          ROCKS_LOG_ERROR(db_options_.info_log,
                          "Unable to get file size: %s: %s", file_path.c_str(),
                          s.ToString().c_str());
          return;
        } else {
          if (file_size > 0) {
            log_file_size = std::max(log_file_size, file_size);
            ++log_files_num;
          } else {
            s = DeleteDBFile(&db_options_, file_path, archival_dir, false,
                             /*force_fg=*/!wal_in_db_path_);
            if (!s.ok()) {
              ROCKS_LOG_WARN(db_options_.info_log,
                             "Unable to delete file: %s: %s", file_path.c_str(),
                             s.ToString().c_str());
              continue;
            } else {
              MutexLock l(&read_first_record_cache_mutex_);
              read_first_record_cache_.erase(number);
            }
          }
        }
      }
    }
  }

  if (0 == log_files_num || !size_limit_enabled) {
    return;
  }

  size_t const files_keep_num = static_cast<size_t>(
      db_options_.WAL_size_limit_MB * 1024 * 1024 / log_file_size);
  if (log_files_num <= files_keep_num) {
    return;
  }

  size_t files_del_num = log_files_num - files_keep_num;
  VectorLogPtr archived_logs;
  s = GetSortedWalsOfType(archival_dir, archived_logs, kArchivedLogFile);
  if (!s.ok()) {
    ROCKS_LOG_WARN(db_options_.info_log,
                   "Unable to get archived WALs from: %s: %s",
                   archival_dir.c_str(), s.ToString().c_str());
    files_del_num = 0;
  } else if (files_del_num > archived_logs.size()) {
    ROCKS_LOG_WARN(db_options_.info_log,
                   "Trying to delete more archived log files than "
                   "exist. Deleting all");
    files_del_num = archived_logs.size();
  }

  for (size_t i = 0; i < files_del_num; ++i) {
    std::string const file_path = archived_logs[i]->PathName();
    s = DeleteDBFile(&db_options_, wal_dir_ + "/" + file_path, wal_dir_, false,
                     /*force_fg=*/!wal_in_db_path_);
    if (!s.ok()) {
      ROCKS_LOG_WARN(db_options_.info_log, "Unable to delete file: %s: %s",
                     file_path.c_str(), s.ToString().c_str());
      continue;
    } else {
      MutexLock l(&read_first_record_cache_mutex_);
      read_first_record_cache_.erase(archived_logs[i]->LogNumber());
    }
  }
}

void WalManager::ArchiveWALFile(const std::string& fname, uint64_t number) {
  auto archived_log_name = ArchivedLogFileName(wal_dir_, number);
  // The sync point below is used in (DBTest,TransactionLogIteratorRace)
  TEST_SYNC_POINT("WalManager::PurgeObsoleteFiles:1");
  Status s = env_->RenameFile(fname, archived_log_name);
  // The sync point below is used in (DBTest,TransactionLogIteratorRace)
  TEST_SYNC_POINT("WalManager::PurgeObsoleteFiles:2");
  ROCKS_LOG_INFO(db_options_.info_log, "Move log file %s to %s -- %s\n",
                 fname.c_str(), archived_log_name.c_str(),
                 s.ToString().c_str());
}

Status WalManager::GetSortedWalsOfType(const std::string& path,
                                       VectorLogPtr& log_files,
                                       WalFileType log_type) {
  std::vector<std::string> all_files;
  const Status status = env_->GetChildren(path, &all_files);
  if (!status.ok()) {
    return status;
  }
  log_files.reserve(all_files.size());
  for (const auto& f : all_files) {
    uint64_t number;
    FileType type;
    if (ParseFileName(f, &number, &type) && type == kWalFile) {
      SequenceNumber sequence;
      Status s = ReadFirstRecord(log_type, number, &sequence);
      if (!s.ok()) {
        return s;
      }
      if (sequence == 0) {
        // empty file
        continue;
      }

      // Reproduce the race condition where a log file is moved
      // to archived dir, between these two sync points, used in
      // (DBTest,TransactionLogIteratorRace)
      TEST_SYNC_POINT("WalManager::GetSortedWalsOfType:1");
      TEST_SYNC_POINT("WalManager::GetSortedWalsOfType:2");

      uint64_t size_bytes;
      s = env_->GetFileSize(LogFileName(path, number), &size_bytes);
      // re-try in case the alive log file has been moved to archive.
      if (!s.ok() && log_type == kAliveLogFile) {
        std::string archived_file = ArchivedLogFileName(path, number);
        if (env_->FileExists(archived_file).ok()) {
          s = env_->GetFileSize(archived_file, &size_bytes);
          if (!s.ok() && env_->FileExists(archived_file).IsNotFound()) {
            // oops, the file just got deleted from archived dir! move on
            s = Status::OK();
            continue;
          }
        }
      }
      if (!s.ok()) {
        return s;
      }

      log_files.push_back(std::unique_ptr<LogFile>(
          new LogFileImpl(number, log_type, sequence, size_bytes)));
    }
  }
  std::sort(
      log_files.begin(), log_files.end(),
      [](const std::unique_ptr<LogFile>& a, const std::unique_ptr<LogFile>& b) {
        LogFileImpl* a_impl = static_cast_with_check<LogFileImpl>(a.get());
        LogFileImpl* b_impl = static_cast_with_check<LogFileImpl>(b.get());
        return *a_impl < *b_impl;
      });
  return status;
}

Status WalManager::RetainProbableWalFiles(VectorLogPtr& all_logs,
                                          const SequenceNumber target) {
  int64_t start = 0;  // signed to avoid overflow when target is < first file.
  int64_t end = static_cast<int64_t>(all_logs.size()) - 1;
  // Binary Search. avoid opening all files.
  while (end >= start) {
    int64_t mid = start + (end - start) / 2;  // Avoid overflow.
    SequenceNumber current_seq_num =
        all_logs.at(static_cast<size_t>(mid))->StartSequence();
    if (current_seq_num == target) {
      end = mid;
      break;
    } else if (current_seq_num < target) {
      start = mid + 1;
    } else {
      end = mid - 1;
    }
  }
  // end could be -ve.
  size_t start_index =
      static_cast<size_t>(std::max(static_cast<int64_t>(0), end));
  // The last wal file is always included
  all_logs.erase(all_logs.begin(), all_logs.begin() + start_index);
  return Status::OK();
}

Status WalManager::ReadFirstRecord(const WalFileType type,
                                   const uint64_t number,
                                   SequenceNumber* sequence) {
  *sequence = 0;
  if (type != kAliveLogFile && type != kArchivedLogFile) {
    ROCKS_LOG_ERROR(db_options_.info_log, "[WalManger] Unknown file type %s",
                    std::to_string(type).c_str());
    return Status::NotSupported("File Type Not Known " + std::to_string(type));
  }
  {
    MutexLock l(&read_first_record_cache_mutex_);
    auto itr = read_first_record_cache_.find(number);
    if (itr != read_first_record_cache_.end()) {
      *sequence = itr->second;
      return Status::OK();
    }
  }
  Status s;
  if (type == kAliveLogFile) {
    std::string fname = LogFileName(wal_dir_, number);
    s = ReadFirstLine(fname, number, sequence);
    if (!s.ok() && env_->FileExists(fname).ok()) {
      // return any error that is not caused by non-existing file
      return s;
    }
  }

  if (type == kArchivedLogFile || !s.ok()) {
    //  check if the file got moved to archive.
    std::string archived_file = ArchivedLogFileName(wal_dir_, number);
    s = ReadFirstLine(archived_file, number, sequence);
    // maybe the file was deleted from archive dir. If that's the case, return
    // Status::OK(). The caller with identify this as empty file because
    // *sequence == 0
    if (!s.ok() && env_->FileExists(archived_file).IsNotFound()) {
      return Status::OK();
    }
  }

  if (s.ok() && *sequence != 0) {
    MutexLock l(&read_first_record_cache_mutex_);
    read_first_record_cache_.insert({number, *sequence});
  }
  return s;
}

Status WalManager::GetLiveWalFile(uint64_t number,
                                  std::unique_ptr<LogFile>* log_file) {
  if (!log_file) {
    return Status::InvalidArgument("log_file not preallocated.");
  }

  if (!number) {
    return Status::PathNotFound("log file not available");
  }

  Status s;

  uint64_t size_bytes;
  s = env_->GetFileSize(LogFileName(wal_dir_, number), &size_bytes);

  if (!s.ok()) {
    return s;
  }

  log_file->reset(new LogFileImpl(number, kAliveLogFile,
                                  0,  // SequenceNumber
                                  size_bytes));

  return Status::OK();
}

// the function returns status.ok() and sequence == 0 if the file exists, but is
// empty
Status WalManager::ReadFirstLine(const std::string& fname,
                                 const uint64_t number,
                                 SequenceNumber* sequence) {
  struct LogReporter : public log::Reader::Reporter {
    Env* env;
    Logger* info_log;
    const char* fname;

    Status* status;
    bool ignore_error;  // true if db_options_.paranoid_checks==false
    void Corruption(size_t bytes, const Status& s) override {
      ROCKS_LOG_WARN(info_log, "[WalManager] %s%s: dropping %d bytes; %s",
                     (this->ignore_error ? "(ignoring error) " : ""), fname,
                     static_cast<int>(bytes), s.ToString().c_str());
      if (this->status->ok()) {
        // only keep the first error
        *this->status = s;
      }
    }
  };

  std::unique_ptr<FSSequentialFile> file;
  Status status = fs_->NewSequentialFile(
      fname, fs_->OptimizeForLogRead(file_options_), &file, nullptr);
  std::unique_ptr<SequentialFileReader> file_reader(
      new SequentialFileReader(std::move(file), fname, io_tracer_));

  if (!status.ok()) {
    return status;
  }

  LogReporter reporter;
  reporter.env = env_;
  reporter.info_log = db_options_.info_log.get();
  reporter.fname = fname.c_str();
  reporter.status = &status;
  reporter.ignore_error = !db_options_.paranoid_checks;
  log::Reader reader(db_options_.info_log, std::move(file_reader), &reporter,
                     true /*checksum*/, number);
  std::string scratch;
  Slice record;

  if (reader.ReadRecord(&record, &scratch) &&
      (status.ok() || !db_options_.paranoid_checks)) {
    if (record.size() < WriteBatchInternal::kHeader) {
      reporter.Corruption(record.size(),
                          Status::Corruption("log record too small"));
      // TODO read record's till the first no corrupt entry?
    } else {
      WriteBatch batch;
      // We can overwrite an existing non-OK Status since it'd only reach here
      // with `paranoid_checks == false`.
      status = WriteBatchInternal::SetContents(&batch, record);
      if (status.ok()) {
        *sequence = WriteBatchInternal::Sequence(&batch);
        return status;
      }
    }
  }

  if (status.ok() && reader.IsCompressedAndEmptyFile()) {
    // In case of wal_compression, it writes a `kSetCompressionType` record
    // which is not associated with any sequence number. As result for an empty
    // file, GetSortedWalsOfType() will skip these WALs causing the operations
    // to fail.
    // Therefore, in order to avoid that failure, it sets sequence_number to 1
    // indicating those WALs should be included.
    *sequence = 1;
  } else {
    // ReadRecord might have returned false on EOF, which means that the log
    // file is empty. Or, a failure may have occurred while processing the first
    // entry. In any case, return status and set sequence number to 0.
    *sequence = 0;
  }
  return status;
}

#endif  // ROCKSDB_LITE
}  // namespace ROCKSDB_NAMESPACE