Fix backup/restore in stress/crash test (#7357)

Summary:
(1) Skip check on specific key if restoring an old backup
(small minority of cases) because it can fail in those cases. (2) Remove
an old assertion about number of column families and number of keys
passed in, which is broken by atomic flush (cf_consistency) test. Like
other code (for better or worse) assume a single key and iterate over
column families. (3) Apply mock_direct_io to NewSequentialFile so that
db_stress backup works on /dev/shm.

Also add more context to output in case of backup/restore db_stress
failure.

Also a minor fix to BackupEngine to report first failure status in
creating new backup, and drop another clue about the potential
source of a "Backup failed" status.

Reverts "Disable backup/restore stress test (https://github.com/facebook/rocksdb/issues/7350)"

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7357

Test Plan:
Using backup_one_in=10000,
"USE_CLANG=1 make crash_test_with_atomic_flush" for 30+ minutes
"USE_CLANG=1 make blackbox_crash_test" for 30+ minutes
And with use_direct_reads with TEST_TMPDIR=/dev/shm/rocksdb

Reviewed By: riversand963

Differential Revision: D23567244

Pulled By: pdillinger

fbshipit-source-id: e77171c2e8394d173917e36898c02dead1c40b77

db_stress_tool/db_stress_test_base.cc

@@ -1217,10 +1217,6 @@ void StressTest::TestCompactFiles(ThreadState* /* thread */,
 Status StressTest::TestBackupRestore(
     ThreadState* thread, const std::vector<int>& rand_column_families,
     const std::vector<int64_t>& rand_keys) {
-  // Note the column families chosen by `rand_column_families` cannot be
-  // dropped while the locks for `rand_keys` are held. So we should not have
-  // to worry about accessing those column families throughout this function.
-  assert(rand_column_families.size() == rand_keys.size());
   std::string backup_dir = FLAGS_db + "/.backup" + ToString(thread->tid);
   std::string restore_dir = FLAGS_db + "/.restore" + ToString(thread->tid);
   BackupableDBOptions backup_opts(backup_dir);
@@ -1249,32 +1245,60 @@ Status StressTest::TestBackupRestore(
     }
   }
   BackupEngine* backup_engine = nullptr;
+  std::string from = "a backup/restore operation";
   Status s = BackupEngine::Open(db_stress_env, backup_opts, &backup_engine);
+  if (!s.ok()) {
+    from = "BackupEngine::Open";
+  }
   if (s.ok()) {
     s = backup_engine->CreateNewBackup(db_);
+    if (!s.ok()) {
+      from = "BackupEngine::CreateNewBackup";
+    }
   }
   if (s.ok()) {
     delete backup_engine;
     backup_engine = nullptr;
     s = BackupEngine::Open(db_stress_env, backup_opts, &backup_engine);
+    if (!s.ok()) {
+      from = "BackupEngine::Open (again)";
+    }
   }
   std::vector<BackupInfo> backup_info;
   if (s.ok()) {
     backup_engine->GetBackupInfo(&backup_info);
     if (backup_info.empty()) {
       s = Status::NotFound("no backups found");
+      from = "BackupEngine::GetBackupInfo";
     }
   }
   if (s.ok() && thread->rand.OneIn(2)) {
     s = backup_engine->VerifyBackup(
         backup_info.front().backup_id,
         thread->rand.OneIn(2) /* verify_with_checksum */);
+    if (!s.ok()) {
+      from = "BackupEngine::VerifyBackup";
+    }
   }
+  bool from_latest = false;
   if (s.ok()) {
     int count = static_cast<int>(backup_info.size());
-    s = backup_engine->RestoreDBFromBackup(
-        RestoreOptions(), backup_info[thread->rand.Uniform(count)].backup_id,
-        restore_dir /* db_dir */, restore_dir /* wal_dir */);
+    if (count > 1) {
+      s = backup_engine->RestoreDBFromBackup(
+          RestoreOptions(), backup_info[thread->rand.Uniform(count)].backup_id,
+          restore_dir /* db_dir */, restore_dir /* wal_dir */);
+      if (!s.ok()) {
+        from = "BackupEngine::RestoreDBFromBackup";
+      }
+    } else {
+      from_latest = true;
+      s = backup_engine->RestoreDBFromLatestBackup(RestoreOptions(),
+                                                   restore_dir /* db_dir */,
+                                                   restore_dir /* wal_dir */);
+      if (!s.ok()) {
+        from = "BackupEngine::RestoreDBFromLatestBackup";
+      }
+    }
   }
   if (s.ok()) {
     uint32_t to_keep = 0;
@@ -1283,6 +1307,9 @@ Status StressTest::TestBackupRestore(
       to_keep = thread->rand.Uniform(3);
     }
     s = backup_engine->PurgeOldBackups(to_keep);
+    if (!s.ok()) {
+      from = "BackupEngine::PurgeOldBackups";
+    }
   }
   DB* restored_db = nullptr;
   std::vector<ColumnFamilyHandle*> restored_cf_handles;
@@ -1300,11 +1327,19 @@ Status StressTest::TestBackupRestore(
     }
     s = DB::Open(DBOptions(restore_options), restore_dir, cf_descriptors,
                  &restored_cf_handles, &restored_db);
+    if (!s.ok()) {
+      from = "DB::Open in backup/restore";
+    }
   }
-  // for simplicity, currently only verifies existence/non-existence of a few
-  // keys
-  for (size_t i = 0; s.ok() && i < rand_column_families.size(); ++i) {
-    std::string key_str = Key(rand_keys[i]);
+  // Note the column families chosen by `rand_column_families` cannot be
+  // dropped while the locks for `rand_keys` are held. So we should not have
+  // to worry about accessing those column families throughout this function.
+  //
+  // For simplicity, currently only verifies existence/non-existence of a
+  // single key
+  for (size_t i = 0; from_latest && s.ok() && i < rand_column_families.size();
+       ++i) {
+    std::string key_str = Key(rand_keys[0]);
     Slice key = key_str;
     std::string restored_value;
     Status get_status = restored_db->Get(
@@ -1321,6 +1356,9 @@ Status StressTest::TestBackupRestore(
       }
     } else {
       s = get_status;
+      if (!s.ok()) {
+        from = "DB::Get in backup/restore";
+      }
     }
   }
   if (backup_engine != nullptr) {
@@ -1335,7 +1373,7 @@ Status StressTest::TestBackupRestore(
     restored_db = nullptr;
   }
   if (!s.ok()) {
-    fprintf(stderr, "A backup/restore operation failed with: %s\n",
+    fprintf(stderr, "Failure in %s with: %s\n", from.c_str(),
             s.ToString().c_str());
   }
   return s;

env/fs_posix.cc

@@ -159,6 +159,7 @@ class PosixFileSystem : public FileSystem {
 #endif  // !ROCKSDB_LITE
 #if !defined(OS_MACOSX) && !defined(OS_OPENBSD) && !defined(OS_SOLARIS)
       flags |= O_DIRECT;
+      TEST_SYNC_POINT_CALLBACK("NewSequentialFile:O_DIRECT", &flags);
 #endif
     }
 

test_util/sync_point.cc

@@ -83,6 +83,11 @@ void SetupSyncPointsToMockDirectIO() {
         int* val = static_cast<int*>(arg);
         *val &= ~O_DIRECT;
       });
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
+      "NewSequentialFile:O_DIRECT", [&](void* arg) {
+        int* val = static_cast<int*>(arg);
+        *val &= ~O_DIRECT;
+      });
   ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
 #endif
 }

tools/db_crashtest.py

@@ -29,6 +29,9 @@ expected_values_file = tempfile.NamedTemporaryFile()
 
 default_params = {
     "acquire_snapshot_one_in": 10000,
+    "backup_max_size": 100 * 1024 * 1024,
+    # Consider larger number when backups considered more stable
+    "backup_one_in": 100000,
     "block_size": 16384,
     "bloom_bits": lambda: random.choice([random.randint(0,19),
                                          random.lognormvariate(2.3, 1.3)]),

utilities/backupable/backupable_db.cc

@@ -1182,7 +1182,9 @@ Status BackupEngineImpl::CreateNewBackupWithMetadata(
       new_backup->SetSequenceNumber(sequence_number);
     }
   }
-  ROCKS_LOG_INFO(options_.info_log, "add files for backup done, wait finish.");
+  ROCKS_LOG_INFO(options_.info_log,
+                 "add files for backup done (%s), wait finish.",
+                 s.ok() ? "OK" : "not OK");
   Status item_status;
   for (auto& item : backup_items_to_finish) {
     item.result.wait();
@@ -1198,7 +1200,7 @@ Status BackupEngineImpl::CreateNewBackupWithMetadata(
           result.custom_checksum_hex, result.checksum_func_name, result.db_id,
           result.db_session_id));
     }
-    if (!item_status.ok()) {
+    if (s.ok() && !item_status.ok()) {
       s = item_status;
     }
   }