Do not set bg error for compaction in retryable IO Error case (#7899)

Summary:
When retryable IO error occurs during compaction, it is mapped to soft error and set the BG error. However, auto resume is not called to clean the soft error since compaction will reschedule by itself. In this change, When retryable IO error occurs during compaction, BG error is not set. User will be informed the error via EventHelper.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7899

Test Plan: tested with error_handler_fs_test

Reviewed By: anand1976

Differential Revision: D26094097

Pulled By: zhichao-cao

fbshipit-source-id: c53424f11d237405592cd762f43cbbdf8da8234f

HISTORY.md

@@ -1,5 +1,7 @@
 # Rocksdb Change Log
 ## Unreleased
+### Behavior Changes
+* When retryable IO error occurs during compaction, it is mapped to soft error and set the BG error. However, auto resume is not called to clean the soft error since compaction will reschedule by itself. In this change, When retryable IO error occurs during compaction, BG error is not set. User will be informed the error via EventHelper.
 
 ## 6.17.0 (01/15/2021)
 ### Behavior Changes

db/db_impl/db_impl.h

@@ -951,6 +951,9 @@ class DBImpl : public DB {
   // is only for the special test of CancelledCompactions
   Status TEST_WaitForCompact(bool waitUnscheduled = false);
 
+  // Get the background error status
+  Status TEST_GetBGError();
+
   // Return the maximum overlapping data (in bytes) at next level for any
   // file at a level >= 1.
   int64_t TEST_MaxNextLevelOverlappingBytes(

db/db_impl/db_impl_debug.cc

@@ -177,6 +177,11 @@ Status DBImpl::TEST_WaitForCompact(bool wait_unscheduled) {
   return error_handler_.GetBGError();
 }
 
+Status DBImpl::TEST_GetBGError() {
+  InstrumentedMutexLock l(&mutex_);
+  return error_handler_.GetBGError();
+}
+
 void DBImpl::TEST_LockMutex() { mutex_.Lock(); }
 
 void DBImpl::TEST_UnlockMutex() { mutex_.Unlock(); }

db/error_handler.cc

@@ -417,11 +417,11 @@ const Status& ErrorHandler::SetBGError(const IOStatus& bg_io_err,
                                           &new_bg_io_err, db_mutex_,
                                           &auto_recovery);
     if (BackgroundErrorReason::kCompaction == reason) {
-      Status bg_err(new_bg_io_err, Status::Severity::kSoftError);
-      if (bg_err.severity() > bg_error_.severity()) {
-        bg_error_ = bg_err;
-      }
-      recover_context_ = context;
+      // We map the retryable IO error during compaction to soft error. Since
+      // compaction can reschedule by itself. We will not set the BG error in
+      // this case
+      // TODO:  a better way to set or clean the retryable IO error which
+      // happens during compaction SST file write.
       return bg_error_;
     } else if (BackgroundErrorReason::kFlushNoWAL == reason ||
                BackgroundErrorReason::kManifestWriteNoWAL == reason) {

db/error_handler_fs_test.cc

@@ -892,15 +892,17 @@ TEST_F(DBErrorHandlingFSTest, CompactionWriteRetryableError) {
   ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
       "CompactionJob::OpenCompactionOutputFile",
       [&](void*) { fault_fs_->SetFilesystemActive(false, error_msg); });
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::BackgroundCompaction:Finish",
+      [&](void*) { CancelAllBackgroundWork(dbfull()); });
   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);
-
+  s = dbfull()->TEST_GetBGError();
+  ASSERT_OK(s);
   fault_fs_->SetFilesystemActive(true);
   SyncPoint::GetInstance()->ClearAllCallBacks();
   SyncPoint::GetInstance()->DisableProcessing();
@@ -940,14 +942,17 @@ TEST_F(DBErrorHandlingFSTest, CompactionWriteFileScopeError) {
   ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
       "CompactionJob::OpenCompactionOutputFile",
       [&](void*) { fault_fs_->SetFilesystemActive(false, error_msg); });
+  ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
+      "DBImpl::BackgroundCompaction:Finish",
+      [&](void*) { CancelAllBackgroundWork(dbfull()); });
   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);
+  s = dbfull()->TEST_GetBGError();
+  ASSERT_OK(s);
 
   fault_fs_->SetFilesystemActive(true);
   SyncPoint::GetInstance()->ClearAllCallBacks();
@@ -2198,8 +2203,7 @@ TEST_F(DBErrorHandlingFSTest, CompactionWriteRetryableErrorAutoRecover) {
   ASSERT_OK(s);
 
   s = dbfull()->TEST_WaitForCompact();
-  ASSERT_EQ(s.severity(), ROCKSDB_NAMESPACE::Status::Severity::kSoftError);
-
+  ASSERT_OK(s);
   TEST_SYNC_POINT("CompactionWriteRetryableErrorAutoRecover0");
   SyncPoint::GetInstance()->ClearAllCallBacks();
   SyncPoint::GetInstance()->DisableProcessing();