Always delete Blob DB files in the background (#4928)

Summary:
Blob DB files are not tracked by the SFM, so they currently don't get
deleted in the background. Force them to be deleted in background so
rate limiting can be applied
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4928

Differential Revision: D13854649

Pulled By: anand1976

fbshipit-source-id: 8031ce66842ff0af440c715d886b377983dad7d8

util/delete_scheduler.cc

@@ -52,11 +52,12 @@ DeleteScheduler::~DeleteScheduler() {
 }
 
 Status DeleteScheduler::DeleteFile(const std::string& file_path,
-                                   const std::string& dir_to_sync) {
+                                   const std::string& dir_to_sync,
+                                   const bool force_bg) {
   Status s;
-  if (rate_bytes_per_sec_.load() <= 0 ||
+  if (rate_bytes_per_sec_.load() <= 0 || (!force_bg &&
       total_trash_size_.load() >
-          sst_file_manager_->GetTotalSize() * max_trash_db_ratio_.load()) {
+          sst_file_manager_->GetTotalSize() * max_trash_db_ratio_.load())) {
     // Rate limiting is disabled or trash size makes up more than
     // max_trash_db_ratio_ (default 25%) of the total DB size
     TEST_SYNC_POINT("DeleteScheduler::DeleteFile");

util/delete_scheduler.h

@@ -46,8 +46,11 @@ class DeleteScheduler {
     rate_bytes_per_sec_.store(bytes_per_sec);
   }
 
-  // Mark file as trash directory and schedule it's deletion
-  Status DeleteFile(const std::string& fname, const std::string& dir_to_sync);
+  // Mark file as trash directory and schedule it's deletion. If force_bg is
+  // set, it forces the file to always be deleted in the background thread,
+  // except when rate limiting is disabled
+  Status DeleteFile(const std::string& fname, const std::string& dir_to_sync,
+      const bool force_bg = false);
 
   // Wait for all files being deleteing in the background to finish or for
   // destructor to be called.

util/file_util.cc

@@ -89,16 +89,23 @@ Status CreateFile(Env* env, const std::string& destination,
 
 Status DeleteSSTFile(const ImmutableDBOptions* db_options,
                      const std::string& fname, const std::string& dir_to_sync) {
+  return DeleteDBFile(db_options, fname, dir_to_sync, false);
+}
+
+Status DeleteDBFile(const ImmutableDBOptions* db_options,
+                     const std::string& fname, const std::string& dir_to_sync,
+                     const bool force_bg) {
 #ifndef ROCKSDB_LITE
   auto sfm =
       static_cast<SstFileManagerImpl*>(db_options->sst_file_manager.get());
   if (sfm) {
-    return sfm->ScheduleFileDeletion(fname, dir_to_sync);
+    return sfm->ScheduleFileDeletion(fname, dir_to_sync, force_bg);
   } else {
     return db_options->env->DeleteFile(fname);
   }
 #else
   (void)dir_to_sync;
+  (void)force_bg;
   // SstFileManager is not supported in ROCKSDB_LITE
   return db_options->env->DeleteFile(fname);
 #endif

util/file_util.h

@@ -25,4 +25,9 @@ extern Status DeleteSSTFile(const ImmutableDBOptions* db_options,
                             const std::string& fname,
                             const std::string& path_to_sync);
 
+extern Status DeleteDBFile(const ImmutableDBOptions* db_options,
+                            const std::string& fname,
+                            const std::string& path_to_sync,
+                            const bool force_bg);
+
 }  // namespace rocksdb

util/sst_file_manager_impl.cc

@@ -402,9 +402,11 @@ bool SstFileManagerImpl::CancelErrorRecovery(ErrorHandler* handler) {
 }
 
 Status SstFileManagerImpl::ScheduleFileDeletion(
-    const std::string& file_path, const std::string& path_to_sync) {
+    const std::string& file_path, const std::string& path_to_sync,
+    const bool force_bg) {
   TEST_SYNC_POINT("SstFileManagerImpl::ScheduleFileDeletion");
-  return delete_scheduler_.DeleteFile(file_path, path_to_sync);
+  return delete_scheduler_.DeleteFile(file_path, path_to_sync,
+                                      force_bg);
 }
 
 void SstFileManagerImpl::WaitForEmptyTrash() {

util/sst_file_manager_impl.h

@@ -111,9 +111,12 @@ class SstFileManagerImpl : public SstFileManager {
   // not guaranteed
   bool CancelErrorRecovery(ErrorHandler* db);
 
-  // Mark file as trash and schedule it's deletion.
+  // Mark file as trash and schedule it's deletion. If force_bg is set, it
+  // forces the file to be deleting in the background regardless of DB size,
+  // except when rate limited delete is disabled
   virtual Status ScheduleFileDeletion(const std::string& file_path,
-                                      const std::string& dir_to_sync);
+                                      const std::string& dir_to_sync,
+                                      const bool force_bg = false);
 
   // Wait for all files being deleteing in the background to finish or for
   // destructor to be called.

utilities/blob_db/blob_db_impl.cc

@@ -1746,8 +1746,8 @@ std::pair<bool, int64_t> BlobDBImpl::DeleteObsoleteFiles(bool aborted) {
                    bfile->PathName().c_str());
 
     blob_files_.erase(bfile->BlobFileNumber());
-    Status s = DeleteSSTFile(&(db_impl_->immutable_db_options()),
-                             bfile->PathName(), blob_dir_);
+    Status s = DeleteDBFile(&(db_impl_->immutable_db_options()),
+                             bfile->PathName(), blob_dir_, true);
     if (!s.ok()) {
       ROCKS_LOG_ERROR(db_options_.info_log,
                       "File failed to be deleted as obsolete %s",
@@ -1837,7 +1837,7 @@ Status DestroyBlobDB(const std::string& dbname, const Options& options,
     uint64_t number;
     FileType type;
     if (ParseFileName(f, &number, &type) && type == kBlobFile) {
-      Status del = DeleteSSTFile(&soptions, blobdir + "/" + f, blobdir);
+      Status del = DeleteDBFile(&soptions, blobdir + "/" + f, blobdir, true);
       if (status.ok() && !del.ok()) {
         status = del;
       }