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Treat File Scope Write IO Error the same as Retryable IO Error (faceb…
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…ook#7840)

Summary:
In RocksDB, when IO error happens, the flags of IOStatus can be set. If the IOStatus is set as "File Scope IO Error", it indicate that the error is constrained in the file level. Since RocksDB does not continues write data to a file when any IO Error happens, File Scope IO Error can be treated the same as Retryable IO Error. Adding the logic to ErrorHandler::SetBGError to include the file scope IO Error in its error handling logic, which is the same as retryable IO Error.

Pull Request resolved: facebook#7840

Test Plan: added new unit tests in error_handler_fs_test. make check

Reviewed By: anand1976

Differential Revision: D25820481

Pulled By: zhichao-cao

fbshipit-source-id: 69cabd3d010073e064d6142ce1cabf341b8a6806
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@zhichao-cao @facebook-github-bot
zhichao-cao authored and facebook-github-bot committed Jan 8, 2021
1 parent cc2a180 commit 48c0843
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1 change: 1 addition & 0 deletions HISTORY.md
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Expand Up @@ -2,6 +2,7 @@
## Unreleased
### Behavior Changes
* When verifying full file checksum with `DB::VerifyFileChecksums()`, we now fail with `Status::InvalidArgument` if the name of the checksum generator used for verification does not match the name of the checksum generator used for protecting the file when it was created.
* Since RocksDB does not continue write the same file if a file write fails for any reason, the file scope write IO error is treated the same as retryable IO error. More information about error handling of file scope IO error is included in `ErrorHandler::SetBGError`.

## 6.16.0 (12/18/2020)
### Behavior Changes
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36 changes: 22 additions & 14 deletions db/error_handler.cc
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Expand Up @@ -350,12 +350,17 @@ const Status& ErrorHandler::SetBGError(const Status& bg_err,

// This is the main function for looking at IO related error during the
// background operations. The main logic is:
// 1) File scope IO error is treated as retryable IO error in the write
// path. In RocksDB, If a file has write IO error and it is at file scope,
// RocksDB never write to the same file again. RocksDB will create a new
// file and rewrite the whole content. Thus, it is retryable.
// 1) if the error is caused by data loss, the error is mapped to
// unrecoverable error. Application/user must take action to handle
// this situation.
// 2) if the error is a Retryable IO error, auto resume will be called and the
// auto resume can be controlled by resume count and resume interval
// options. There are three sub-cases:
// this situation (File scope case is excluded).
// 2) if the error is a Retryable IO error (i.e., it is a file scope IO error,
// or its retryable flag is set and not a data loss error), auto resume
// will be called and the auto resume can be controlled by resume count
// and resume interval options. There are three sub-cases:
// a) if the error happens during compaction, it is mapped to a soft error.
// the compaction thread will reschedule a new compaction.
// b) if the error happens during flush and also WAL is empty, it is mapped
Expand Down Expand Up @@ -384,9 +389,10 @@ const Status& ErrorHandler::SetBGError(const IOStatus& bg_io_err,

Status new_bg_io_err = bg_io_err;
DBRecoverContext context;
if (bg_io_err.GetDataLoss()) {
// First, data loss is treated as unrecoverable error. So it can directly
// overwrite any existing bg_error_.
if (bg_io_err.GetScope() != IOStatus::IOErrorScope::kIOErrorScopeFile &&
bg_io_err.GetDataLoss()) {
// First, data loss (non file scope) is treated as unrecoverable error. So
// it can directly overwrite any existing bg_error_.
bool auto_recovery = false;
Status bg_err(new_bg_io_err, Status::Severity::kUnrecoverableError);
bg_error_ = bg_err;
Expand All @@ -397,13 +403,15 @@ const Status& ErrorHandler::SetBGError(const IOStatus& bg_io_err,
&bg_err, db_mutex_, &auto_recovery);
recover_context_ = context;
return bg_error_;
} else if (bg_io_err.GetRetryable()) {
// Second, check if the error is a retryable IO error or not. if it is
// retryable error and its severity is higher than bg_error_, overwrite
// the bg_error_ with new error.
// In current stage, for retryable IO error of compaction, treat it as
// soft error. In other cases, treat the retryable IO error as hard
// error.
} else if (bg_io_err.GetScope() ==
IOStatus::IOErrorScope::kIOErrorScopeFile ||
bg_io_err.GetRetryable()) {
// Second, check if the error is a retryable IO error (file scope IO error
// is also treated as retryable IO error in RocksDB write path). if it is
// retryable error and its severity is higher than bg_error_, overwrite the
// bg_error_ with new error. In current stage, for retryable IO error of
// compaction, treat it as soft error. In other cases, treat the retryable
// IO error as hard error.
bool auto_recovery = false;
EventHelpers::NotifyOnBackgroundError(db_options_.listeners, reason,
&new_bg_io_err, db_mutex_,
Expand Down
178 changes: 178 additions & 0 deletions db/error_handler_fs_test.cc
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Expand Up @@ -241,6 +241,90 @@ TEST_F(DBErrorHandlingFSTest, FLushWritRetryableError) {
Destroy(options);
}

TEST_F(DBErrorHandlingFSTest, FLushWritFileScopeError) {
std::shared_ptr<ErrorHandlerFSListener> listener(
new ErrorHandlerFSListener());
Options options = GetDefaultOptions();
options.env = fault_env_.get();
options.create_if_missing = true;
options.listeners.emplace_back(listener);
options.max_bgerror_resume_count = 0;
Status s;

listener->EnableAutoRecovery(false);
DestroyAndReopen(options);

IOStatus error_msg = IOStatus::IOError("File Scope Data Loss Error");
error_msg.SetDataLoss(true);
error_msg.SetScope(
ROCKSDB_NAMESPACE::IOStatus::IOErrorScope::kIOErrorScopeFile);
error_msg.SetRetryable(false);

ASSERT_OK(Put(Key(1), "val1"));
SyncPoint::GetInstance()->SetCallBack(
"BuildTable:BeforeFinishBuildTable",
[&](void*) { fault_fs_->SetFilesystemActive(false, error_msg); });
SyncPoint::GetInstance()->EnableProcessing();
s = Flush();
ASSERT_EQ(s.severity(), ROCKSDB_NAMESPACE::Status::Severity::kHardError);
SyncPoint::GetInstance()->DisableProcessing();
fault_fs_->SetFilesystemActive(true);
s = dbfull()->Resume();
ASSERT_OK(s);
Reopen(options);
ASSERT_EQ("val1", Get(Key(1)));

ASSERT_OK(Put(Key(2), "val2"));
SyncPoint::GetInstance()->SetCallBack(
"BuildTable:BeforeSyncTable",
[&](void*) { fault_fs_->SetFilesystemActive(false, error_msg); });
SyncPoint::GetInstance()->EnableProcessing();
s = Flush();
ASSERT_EQ(s.severity(), ROCKSDB_NAMESPACE::Status::Severity::kHardError);
SyncPoint::GetInstance()->DisableProcessing();
fault_fs_->SetFilesystemActive(true);
s = dbfull()->Resume();
ASSERT_OK(s);
Reopen(options);
ASSERT_EQ("val2", Get(Key(2)));

ASSERT_OK(Put(Key(3), "val3"));
SyncPoint::GetInstance()->SetCallBack(
"BuildTable:BeforeCloseTableFile",
[&](void*) { fault_fs_->SetFilesystemActive(false, error_msg); });
SyncPoint::GetInstance()->EnableProcessing();
s = Flush();
ASSERT_EQ(s.severity(), ROCKSDB_NAMESPACE::Status::Severity::kHardError);
SyncPoint::GetInstance()->DisableProcessing();
fault_fs_->SetFilesystemActive(true);
s = dbfull()->Resume();
ASSERT_OK(s);
Reopen(options);
ASSERT_EQ("val3", Get(Key(3)));

// not file scope, but retyrable set
error_msg.SetDataLoss(false);
error_msg.SetScope(
ROCKSDB_NAMESPACE::IOStatus::IOErrorScope::kIOErrorScopeFileSystem);
error_msg.SetRetryable(true);

ASSERT_OK(Put(Key(3), "val3"));
SyncPoint::GetInstance()->SetCallBack(
"BuildTable:BeforeCloseTableFile",
[&](void*) { fault_fs_->SetFilesystemActive(false, error_msg); });
SyncPoint::GetInstance()->EnableProcessing();
s = Flush();
ASSERT_EQ(s.severity(), ROCKSDB_NAMESPACE::Status::Severity::kHardError);
SyncPoint::GetInstance()->DisableProcessing();
fault_fs_->SetFilesystemActive(true);
s = dbfull()->Resume();
ASSERT_OK(s);
Reopen(options);
ASSERT_EQ("val3", Get(Key(3)));

Destroy(options);
}

TEST_F(DBErrorHandlingFSTest, FLushWritNoWALRetryableError1) {
std::shared_ptr<ErrorHandlerFSListener> listener(
new ErrorHandlerFSListener());
Expand Down Expand Up @@ -453,6 +537,52 @@ TEST_F(DBErrorHandlingFSTest, ManifestWriteRetryableError) {
Close();
}

TEST_F(DBErrorHandlingFSTest, ManifestWriteFileScopeError) {
std::shared_ptr<ErrorHandlerFSListener> listener(
new ErrorHandlerFSListener());
Options options = GetDefaultOptions();
options.env = fault_env_.get();
options.create_if_missing = true;
options.listeners.emplace_back(listener);
options.max_bgerror_resume_count = 0;
Status s;
std::string old_manifest;
std::string new_manifest;

listener->EnableAutoRecovery(false);
DestroyAndReopen(options);
old_manifest = GetManifestNameFromLiveFiles();

IOStatus error_msg = IOStatus::IOError("File Scope Data Loss Error");
error_msg.SetDataLoss(true);
error_msg.SetScope(
ROCKSDB_NAMESPACE::IOStatus::IOErrorScope::kIOErrorScopeFile);
error_msg.SetRetryable(false);

ASSERT_OK(Put(Key(0), "val"));
ASSERT_OK(Flush());
ASSERT_OK(Put(Key(1), "val"));
SyncPoint::GetInstance()->SetCallBack(
"VersionSet::LogAndApply:WriteManifest",
[&](void*) { fault_fs_->SetFilesystemActive(false, error_msg); });
SyncPoint::GetInstance()->EnableProcessing();
s = Flush();
ASSERT_EQ(s.severity(), ROCKSDB_NAMESPACE::Status::Severity::kHardError);
SyncPoint::GetInstance()->ClearAllCallBacks();
SyncPoint::GetInstance()->DisableProcessing();
fault_fs_->SetFilesystemActive(true);
s = dbfull()->Resume();
ASSERT_OK(s);

new_manifest = GetManifestNameFromLiveFiles();
ASSERT_NE(new_manifest, old_manifest);

Reopen(options);
ASSERT_EQ("val", Get(Key(0)));
ASSERT_EQ("val", Get(Key(1)));
Close();
}

TEST_F(DBErrorHandlingFSTest, ManifestWriteNoWALRetryableError) {
std::shared_ptr<ErrorHandlerFSListener> listener(
new ErrorHandlerFSListener());
Expand Down Expand Up @@ -779,6 +909,54 @@ TEST_F(DBErrorHandlingFSTest, CompactionWriteRetryableError) {
Destroy(options);
}

TEST_F(DBErrorHandlingFSTest, CompactionWriteFileScopeError) {
std::shared_ptr<ErrorHandlerFSListener> listener(
new ErrorHandlerFSListener());
Options options = GetDefaultOptions();
options.env = fault_env_.get();
options.create_if_missing = true;
options.level0_file_num_compaction_trigger = 2;
options.listeners.emplace_back(listener);
options.max_bgerror_resume_count = 0;
Status s;
DestroyAndReopen(options);

IOStatus error_msg = IOStatus::IOError("File Scope Data Loss Error");
error_msg.SetDataLoss(true);
error_msg.SetScope(
ROCKSDB_NAMESPACE::IOStatus::IOErrorScope::kIOErrorScopeFile);
error_msg.SetRetryable(false);

ASSERT_OK(Put(Key(0), "va;"));
ASSERT_OK(Put(Key(2), "va;"));
s = Flush();
ASSERT_OK(s);

listener->OverrideBGError(Status(error_msg, Status::Severity::kHardError));
listener->EnableAutoRecovery(false);
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->LoadDependency(
{{"DBImpl::FlushMemTable:FlushMemTableFinished",
"BackgroundCallCompaction:0"}});
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
"CompactionJob::OpenCompactionOutputFile",
[&](void*) { fault_fs_->SetFilesystemActive(false, error_msg); });
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();

ASSERT_OK(Put(Key(1), "val"));
s = Flush();
ASSERT_OK(s);

s = dbfull()->TEST_WaitForCompact();
ASSERT_EQ(s.severity(), ROCKSDB_NAMESPACE::Status::Severity::kSoftError);

fault_fs_->SetFilesystemActive(true);
SyncPoint::GetInstance()->ClearAllCallBacks();
SyncPoint::GetInstance()->DisableProcessing();
s = dbfull()->Resume();
ASSERT_OK(s);
Destroy(options);
}

TEST_F(DBErrorHandlingFSTest, CorruptionError) {
Options options = GetDefaultOptions();
options.env = fault_env_.get();
Expand Down

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