Refactor with VersionEditHandler (#6581)

Summary:
Added a few classes in the same class hierarchy to remove code duplication and
refactor the logic of reading and processing MANIFEST files.

New classes are as follows.
```
class VersionEditHandlerBase;
class ListColumnFamiliesHandler : VersionEditHandlerBase;
class FileChecksumRetriever : VersionEditHandlerBase;
class DumpManifestHandler : VersionEditHandler;
```
Classes that already existed before this PR are as follows.
```
class VersionEditHandler : VersionEditHandlerBase;
```

With these classes, refactored functions: `VersionSet::Recover()`,
`VersionSet::ListColumnFamilies()`, `VersionSet::DumpManifest()`,
`GetFileChecksumFromManifest()`.

Test Plan (devserver):
```
make check
COMPILE_WITH_ASAN=1 make check
```
These refactored code, especially recovery-related logic, will be tested intensively by
all existing unit tests and stress tests. For example, run
```
make crash_test
```
Verified 3 successful runs on devserver.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/6581

Reviewed By: ajkr

Differential Revision: D20616217

Pulled By: riversand963

fbshipit-source-id: 048c7743aa4be2623ccd0cc3e61c0027e604e78b

db/corruption_test.cc

@@ -32,6 +32,7 @@
 #include "table/mock_table.h"
 #include "test_util/testharness.h"
 #include "test_util/testutil.h"
+#include "util/cast_util.h"
 #include "util/random.h"
 #include "util/string_util.h"
 
@@ -552,7 +553,7 @@ TEST_F(CorruptionTest, FileSystemStateCorrupted) {
     DBImpl* dbi = static_cast_with_check<DBImpl>(db_);
     std::vector<LiveFileMetaData> metadata;
     dbi->GetLiveFilesMetaData(&metadata);
-    ASSERT_GT(metadata.size(), size_t(0));
+    ASSERT_GT(metadata.size(), 0);
     std::string filename = dbname_ + metadata[0].name;
 
     delete db_;
@@ -568,7 +569,7 @@ TEST_F(CorruptionTest, FileSystemStateCorrupted) {
     } else {  // delete the file
       ASSERT_OK(env_.DeleteFile(filename));
       Status x = TryReopen(&options);
-      ASSERT_TRUE(x.IsPathNotFound());
+      ASSERT_TRUE(x.IsCorruption());
     }
 
     ASSERT_OK(DestroyDB(dbname_, options_));

db/version_edit.h

@@ -533,8 +533,11 @@ class VersionEdit {
 
  private:
   friend class ReactiveVersionSet;
+  friend class VersionEditHandlerBase;
+  friend class ListColumnFamiliesHandler;
   friend class VersionEditHandler;
   friend class VersionEditHandlerPointInTime;
+  friend class DumpManifestHandler;
   friend class VersionSet;
   friend class Version;
   friend class AtomicGroupReadBuffer;

db/version_edit_handler.cc

@@ -9,28 +9,14 @@
 
 #include "db/version_edit_handler.h"
 
+#include <cinttypes>
+
 #include "monitoring/persistent_stats_history.h"
 
 namespace ROCKSDB_NAMESPACE {
 
-VersionEditHandler::VersionEditHandler(
-    bool read_only, const std::vector<ColumnFamilyDescriptor>& column_families,
-    VersionSet* version_set, bool track_missing_files,
-    bool no_error_if_table_files_missing,
-    const std::shared_ptr<IOTracer>& io_tracer)
-    : read_only_(read_only),
-      column_families_(column_families),
-      status_(),
-      version_set_(version_set),
-      track_missing_files_(track_missing_files),
-      no_error_if_table_files_missing_(no_error_if_table_files_missing),
-      initialized_(false),
-      io_tracer_(io_tracer) {
-  assert(version_set_ != nullptr);
-}
-
-void VersionEditHandler::Iterate(log::Reader& reader, Status* log_read_status,
-                                 std::string* db_id) {
+void VersionEditHandlerBase::Iterate(log::Reader& reader,
+                                     Status* log_read_status) {
   Slice record;
   std::string scratch;
   assert(log_read_status);
@@ -38,19 +24,14 @@ void VersionEditHandler::Iterate(log::Reader& reader, Status* log_read_status,
 
   size_t recovered_edits = 0;
   Status s = Initialize();
-  while (s.ok() && reader.ReadRecord(&record, &scratch) &&
-         log_read_status->ok()) {
+  while (reader.LastRecordEnd() < max_manifest_read_size_ && s.ok() &&
+         reader.ReadRecord(&record, &scratch) && log_read_status->ok()) {
     VersionEdit edit;
     s = edit.DecodeFrom(record);
     if (!s.ok()) {
       break;
     }
-    if (edit.has_db_id_) {
-      version_set_->db_id_ = edit.GetDbId();
-      if (db_id != nullptr) {
-        *db_id = version_set_->db_id_;
-      }
-    }
+
     s = read_buffer_.AddEdit(&edit);
     if (!s.ok()) {
       break;
@@ -81,11 +62,67 @@ void VersionEditHandler::Iterate(log::Reader& reader, Status* log_read_status,
     s = *log_read_status;
   }
 
+  read_buffer_.Clear();
+
   CheckIterationResult(reader, &s);
 
   if (!s.ok()) {
     status_ = s;
   }
+  TEST_SYNC_POINT_CALLBACK("VersionEditHandlerBase::Iterate:Finish",
+                           &recovered_edits);
+}
+
+Status ListColumnFamiliesHandler::ApplyVersionEdit(
+    VersionEdit& edit, ColumnFamilyData** /*unused*/) {
+  Status s;
+  if (edit.is_column_family_add_) {
+    if (column_family_names_.find(edit.column_family_) !=
+        column_family_names_.end()) {
+      s = Status::Corruption("Manifest adding the same column family twice");
+    } else {
+      column_family_names_.insert(
+          {edit.column_family_, edit.column_family_name_});
+    }
+  } else if (edit.is_column_family_drop_) {
+    if (column_family_names_.find(edit.column_family_) ==
+        column_family_names_.end()) {
+      s = Status::Corruption("Manifest - dropping non-existing column family");
+    } else {
+      column_family_names_.erase(edit.column_family_);
+    }
+  }
+  return s;
+}
+
+Status FileChecksumRetriever::ApplyVersionEdit(VersionEdit& edit,
+                                               ColumnFamilyData** /*unused*/) {
+  for (const auto& deleted_file : edit.GetDeletedFiles()) {
+    file_checksum_list_.RemoveOneFileChecksum(deleted_file.second);
+  }
+  for (const auto& new_file : edit.GetNewFiles()) {
+    file_checksum_list_.InsertOneFileChecksum(
+        new_file.second.fd.GetNumber(), new_file.second.file_checksum,
+        new_file.second.file_checksum_func_name);
+  }
+  return Status::OK();
+}
+
+VersionEditHandler::VersionEditHandler(
+    bool read_only, const std::vector<ColumnFamilyDescriptor>& column_families,
+    VersionSet* version_set, bool track_missing_files,
+    bool no_error_if_table_files_missing,
+    const std::shared_ptr<IOTracer>& io_tracer, bool skip_load_table_files)
+    : VersionEditHandlerBase(),
+      read_only_(read_only),
+      column_families_(column_families),
+      version_set_(version_set),
+      track_missing_files_(track_missing_files),
+      no_error_if_table_files_missing_(no_error_if_table_files_missing),
+      io_tracer_(io_tracer),
+      skip_load_table_files_(skip_load_table_files),
+      initialized_(false) {
+  assert(version_set_ != nullptr);
 }
 
 Status VersionEditHandler::Initialize() {
@@ -274,7 +311,7 @@ void VersionEditHandler::CheckIterationResult(const log::Reader& reader,
                                               Status* s) {
   assert(s != nullptr);
   if (!s->ok()) {
-    read_buffer_.Clear();
+    // Do nothing here.
   } else if (!version_edit_params_.has_log_number_ ||
              !version_edit_params_.has_next_file_number_ ||
              !version_edit_params_.has_last_sequence_) {
@@ -292,6 +329,8 @@ void VersionEditHandler::CheckIterationResult(const log::Reader& reader,
     msg.append(" entry in MANIFEST");
     *s = Status::Corruption(msg);
   }
+  // There were some column families in the MANIFEST that weren't specified
+  // in the argument. This is OK in read_only mode
   if (s->ok() && !read_only_ && !column_families_not_found_.empty()) {
     std::string msg;
     for (const auto& cf : column_families_not_found_) {
@@ -330,6 +369,10 @@ void VersionEditHandler::CheckIterationResult(const log::Reader& reader,
       *s = LoadTables(cfd, /*prefetch_index_and_filter_in_cache=*/false,
                       /*is_initial_load=*/true);
       if (!s->ok()) {
+        // If s is IOError::PathNotFound, then we mark the db as corrupted.
+        if (s->IsPathNotFound()) {
+          *s = Status::Corruption("Corruption: " + s->ToString());
+        }
         break;
       }
     }
@@ -426,6 +469,9 @@ Status VersionEditHandler::MaybeCreateVersion(const VersionEdit& /*edit*/,
 Status VersionEditHandler::LoadTables(ColumnFamilyData* cfd,
                                       bool prefetch_index_and_filter_in_cache,
                                       bool is_initial_load) {
+  if (skip_load_table_files_) {
+    return Status::OK();
+  }
   assert(cfd != nullptr);
   assert(!cfd->IsDropped());
   auto builder_iter = builders_.find(cfd->GetID());
@@ -452,10 +498,11 @@ Status VersionEditHandler::LoadTables(ColumnFamilyData* cfd,
 Status VersionEditHandler::ExtractInfoFromVersionEdit(ColumnFamilyData* cfd,
                                                       const VersionEdit& edit) {
   Status s;
+  if (edit.has_db_id_) {
+    version_set_->db_id_ = edit.GetDbId();
+    version_edit_params_.SetDBId(edit.db_id_);
+  }
   if (cfd != nullptr) {
-    if (edit.has_db_id_) {
-      version_edit_params_.SetDBId(edit.db_id_);
-    }
     if (edit.has_log_number_) {
       if (cfd->GetLogNumber() > edit.log_number_) {
         ROCKS_LOG_WARN(
@@ -505,8 +552,7 @@ VersionEditHandlerPointInTime::VersionEditHandlerPointInTime(
     VersionSet* version_set, const std::shared_ptr<IOTracer>& io_tracer)
     : VersionEditHandler(read_only, column_families, version_set,
                          /*track_missing_files=*/true,
-                         /*no_error_if_table_files_missing=*/true, io_tracer),
-      io_tracer_(io_tracer) {}
+                         /*no_error_if_table_files_missing=*/true, io_tracer) {}
 
 VersionEditHandlerPointInTime::~VersionEditHandlerPointInTime() {
   for (const auto& elem : versions_) {
@@ -612,4 +658,32 @@ Status VersionEditHandlerPointInTime::MaybeCreateVersion(
   return s;
 }
 
+void DumpManifestHandler::CheckIterationResult(const log::Reader& reader,
+                                               Status* s) {
+  VersionEditHandler::CheckIterationResult(reader, s);
+  if (!s->ok()) {
+    fprintf(stdout, "%s\n", s->ToString().c_str());
+    return;
+  }
+  for (auto* cfd : *(version_set_->column_family_set_)) {
+    fprintf(stdout,
+            "--------------- Column family \"%s\"  (ID %" PRIu32
+            ") --------------\n",
+            cfd->GetName().c_str(), cfd->GetID());
+    fprintf(stdout, "log number: %" PRIu64 "\n", cfd->GetLogNumber());
+    fprintf(stdout, "comparator: %s\n", cfd->user_comparator()->Name());
+    assert(cfd->current());
+    fprintf(stdout, "%s \n", cfd->current()->DebugString(hex_).c_str());
+  }
+  fprintf(stdout,
+          "next_file_number %" PRIu64 " last_sequence %" PRIu64
+          "  prev_log_number %" PRIu64 " max_column_family %" PRIu32
+          " min_log_number_to_keep "
+          "%" PRIu64 "\n",
+          version_set_->current_next_file_number(),
+          version_set_->LastSequence(), version_set_->prev_log_number(),
+          version_set_->column_family_set_->GetMaxColumnFamily(),
+          version_set_->min_log_number_to_keep_2pc());
+}
+
 }  // namespace ROCKSDB_NAMESPACE

db/version_edit_handler.h

@@ -15,7 +15,73 @@
 
 namespace ROCKSDB_NAMESPACE {
 
-typedef std::unique_ptr<BaseReferencedVersionBuilder> VersionBuilderUPtr;
+class VersionEditHandlerBase {
+ public:
+  explicit VersionEditHandlerBase()
+      : max_manifest_read_size_(std::numeric_limits<uint64_t>::max()) {}
+
+  virtual ~VersionEditHandlerBase() {}
+
+  void Iterate(log::Reader& reader, Status* log_read_status);
+
+  const Status& status() const { return status_; }
+
+ protected:
+  explicit VersionEditHandlerBase(uint64_t max_read_size)
+      : max_manifest_read_size_(max_read_size) {}
+  virtual Status Initialize() { return Status::OK(); }
+
+  virtual Status ApplyVersionEdit(VersionEdit& edit,
+                                  ColumnFamilyData** cfd) = 0;
+
+  virtual void CheckIterationResult(const log::Reader& /*reader*/,
+                                    Status* /*s*/) {}
+
+  Status status_;
+
+ private:
+  AtomicGroupReadBuffer read_buffer_;
+  const uint64_t max_manifest_read_size_;
+};
+
+class ListColumnFamiliesHandler : public VersionEditHandlerBase {
+ public:
+  ListColumnFamiliesHandler() : VersionEditHandlerBase() {}
+
+  ~ListColumnFamiliesHandler() override {}
+
+  const std::map<uint32_t, std::string> GetColumnFamilyNames() const {
+    return column_family_names_;
+  }
+
+ protected:
+  Status ApplyVersionEdit(VersionEdit& edit,
+                          ColumnFamilyData** /*unused*/) override;
+
+ private:
+  // default column family is always implicitly there
+  std::map<uint32_t, std::string> column_family_names_{
+      {0, kDefaultColumnFamilyName}};
+};
+
+class FileChecksumRetriever : public VersionEditHandlerBase {
+ public:
+  FileChecksumRetriever(uint64_t max_read_size,
+                        FileChecksumList& file_checksum_list)
+      : VersionEditHandlerBase(max_read_size),
+        file_checksum_list_(file_checksum_list) {}
+
+  ~FileChecksumRetriever() override {}
+
+ protected:
+  Status ApplyVersionEdit(VersionEdit& edit,
+                          ColumnFamilyData** /*unused*/) override;
+
+ private:
+  FileChecksumList& file_checksum_list_;
+};
+
+using VersionBuilderUPtr = std::unique_ptr<BaseReferencedVersionBuilder>;
 
 // A class used for scanning MANIFEST file.
 // VersionEditHandler reads a MANIFEST file, parses the version edits, and
@@ -24,31 +90,48 @@ typedef std::unique_ptr<BaseReferencedVersionBuilder> VersionBuilderUPtr;
 // To use this class and its subclasses,
 // 1. Create an object of VersionEditHandler or its subclasses.
 //    VersionEditHandler handler(read_only, column_families, version_set,
-//                               track_missing_files, ignore_missing_files);
+//                               track_missing_files,
+//                               no_error_if_table_files_missing);
 // 2. Status s = handler.Iterate(reader, &db_id);
 // 3. Check s and handle possible errors.
 //
 // Not thread-safe, external synchronization is necessary if an object of
 // VersionEditHandler is shared by multiple threads.
-class VersionEditHandler {
+class VersionEditHandler : public VersionEditHandlerBase {
  public:
   explicit VersionEditHandler(
       bool read_only,
       const std::vector<ColumnFamilyDescriptor>& column_families,
       VersionSet* version_set, bool track_missing_files,
-      bool ignore_missing_files, const std::shared_ptr<IOTracer>& io_tracer);
-
-  virtual ~VersionEditHandler() {}
+      bool no_error_if_table_files_missing,
+      const std::shared_ptr<IOTracer>& io_tracer)
+      : VersionEditHandler(read_only, column_families, version_set,
+                           track_missing_files, no_error_if_table_files_missing,
+                           io_tracer, /*skip_load_table_files=*/false) {}
 
-  void Iterate(log::Reader& reader, Status* log_read_status,
-               std::string* db_id);
+  ~VersionEditHandler() override {}
 
-  const Status& status() const { return status_; }
+  const VersionEditParams& GetVersionEditParams() const {
+    return version_edit_params_;
+  }
 
   bool HasMissingFiles() const;
 
+  void GetDbId(std::string* db_id) const {
+    if (db_id && version_edit_params_.has_db_id_) {
+      *db_id = version_edit_params_.db_id_;
+    }
+  }
+
  protected:
-  Status ApplyVersionEdit(VersionEdit& edit, ColumnFamilyData** cfd);
+  explicit VersionEditHandler(
+      bool read_only,
+      const std::vector<ColumnFamilyDescriptor>& column_families,
+      VersionSet* version_set, bool track_missing_files,
+      bool no_error_if_table_files_missing,
+      const std::shared_ptr<IOTracer>& io_tracer, bool skip_load_table_files);
+
+  Status ApplyVersionEdit(VersionEdit& edit, ColumnFamilyData** cfd) override;
 
   Status OnColumnFamilyAdd(VersionEdit& edit, ColumnFamilyData** cfd);
 
@@ -60,12 +143,12 @@ class VersionEditHandler {
 
   Status OnWalDeletion(VersionEdit& edit);
 
-  Status Initialize();
+  Status Initialize() override;
 
   void CheckColumnFamilyId(const VersionEdit& edit, bool* cf_in_not_found,
                            bool* cf_in_builders) const;
 
-  virtual void CheckIterationResult(const log::Reader& reader, Status* s);
+  void CheckIterationResult(const log::Reader& reader, Status* s) override;
 
   ColumnFamilyData* CreateCfAndInit(const ColumnFamilyOptions& cf_options,
                                     const VersionEdit& edit);
@@ -82,24 +165,26 @@ class VersionEditHandler {
 
   const bool read_only_;
   const std::vector<ColumnFamilyDescriptor>& column_families_;
-  Status status_;
   VersionSet* version_set_;
-  AtomicGroupReadBuffer read_buffer_;
   std::unordered_map<uint32_t, VersionBuilderUPtr> builders_;
   std::unordered_map<std::string, ColumnFamilyOptions> name_to_options_;
+  // Keeps track of column families in manifest that were not found in
+  // column families parameters. if those column families are not dropped
+  // by subsequent manifest records, Recover() will return failure status.
   std::unordered_map<uint32_t, std::string> column_families_not_found_;
   VersionEditParams version_edit_params_;
   const bool track_missing_files_;
   std::unordered_map<uint32_t, std::unordered_set<uint64_t>>
       cf_to_missing_files_;
   bool no_error_if_table_files_missing_;
+  std::shared_ptr<IOTracer> io_tracer_;
+  bool skip_load_table_files_;
 
  private:
   Status ExtractInfoFromVersionEdit(ColumnFamilyData* cfd,
                                     const VersionEdit& edit);
 
   bool initialized_;
-  std::shared_ptr<IOTracer> io_tracer_;
 };
 
 // A class similar to its base class, i.e. VersionEditHandler.
@@ -124,7 +209,44 @@ class VersionEditHandlerPointInTime : public VersionEditHandler {
 
  private:
   std::unordered_map<uint32_t, Version*> versions_;
-  std::shared_ptr<IOTracer> io_tracer_;
+};
+
+class DumpManifestHandler : public VersionEditHandler {
+ public:
+  DumpManifestHandler(
+      const std::vector<ColumnFamilyDescriptor>& column_families,
+      VersionSet* version_set, const std::shared_ptr<IOTracer>& io_tracer,
+      bool verbose, bool hex, bool json)
+      : VersionEditHandler(
+            /*read_only=*/true, column_families, version_set,
+            /*track_missing_files=*/false,
+            /*no_error_if_table_files_missing=*/false, io_tracer,
+            /*skip_load_table_files=*/true),
+        verbose_(verbose),
+        hex_(hex),
+        json_(json),
+        count_(0) {}
+
+  ~DumpManifestHandler() override {}
+
+  Status ApplyVersionEdit(VersionEdit& edit, ColumnFamilyData** cfd) override {
+    // Write out each individual edit
+    if (verbose_ && !json_) {
+      fprintf(stdout, "%s\n", edit.DebugString(hex_).c_str());
+    } else if (json_) {
+      fprintf(stdout, "%s\n", edit.DebugJSON(count_, hex_).c_str());
+    }
+    ++count_;
+    return VersionEditHandler::ApplyVersionEdit(edit, cfd);
+  }
+
+  void CheckIterationResult(const log::Reader& reader, Status* s) override;
+
+ private:
+  const bool verbose_;
+  const bool hex_;
+  const bool json_;
+  int count_;
 };
 
 }  // namespace ROCKSDB_NAMESPACE

db/version_set.cc

@@ -4713,15 +4713,6 @@ Status VersionSet::ReadAndRecover(
 Status VersionSet::Recover(
     const std::vector<ColumnFamilyDescriptor>& column_families, bool read_only,
     std::string* db_id) {
-  std::unordered_map<std::string, ColumnFamilyOptions> cf_name_to_options;
-  for (const auto& cf : column_families) {
-    cf_name_to_options.emplace(cf.name, cf.options);
-  }
-  // keeps track of column families in manifest that were not found in
-  // column families parameters. if those column families are not dropped
-  // by subsequent manifest records, Recover() will return failure status
-  std::unordered_map<int, std::string> column_families_not_found;
-
   // Read "CURRENT" file, which contains a pointer to the current manifest file
   std::string manifest_path;
   Status s = GetCurrentManifestPath(dbname_, fs_.get(), &manifest_path,
@@ -4746,139 +4737,30 @@ Status VersionSet::Recover(
         new SequentialFileReader(std::move(manifest_file), manifest_path,
                                  db_options_->log_readahead_size, io_tracer_));
   }
-
-  VersionBuilderMap builders;
-
-  // add default column family
-  auto default_cf_iter = cf_name_to_options.find(kDefaultColumnFamilyName);
-  if (default_cf_iter == cf_name_to_options.end()) {
-    return Status::InvalidArgument("Default column family not specified");
-  }
-  VersionEdit default_cf_edit;
-  default_cf_edit.AddColumnFamily(kDefaultColumnFamilyName);
-  default_cf_edit.SetColumnFamily(0);
-  ColumnFamilyData* default_cfd =
-      CreateColumnFamily(default_cf_iter->second, &default_cf_edit);
-  // In recovery, nobody else can access it, so it's fine to set it to be
-  // initialized earlier.
-  default_cfd->set_initialized();
-  builders.insert(
-      std::make_pair(0, std::unique_ptr<BaseReferencedVersionBuilder>(
-                            new BaseReferencedVersionBuilder(default_cfd))));
   uint64_t current_manifest_file_size = 0;
-  VersionEditParams version_edit_params;
+  uint64_t log_number = 0;
   {
     VersionSet::LogReporter reporter;
     Status log_read_status;
     reporter.status = &log_read_status;
     log::Reader reader(nullptr, std::move(manifest_file_reader), &reporter,
                        true /* checksum */, 0 /* log_number */);
-    AtomicGroupReadBuffer read_buffer;
-    s = ReadAndRecover(reader, &read_buffer, cf_name_to_options,
-                       column_families_not_found, builders, &log_read_status,
-                       &version_edit_params, db_id);
-    current_manifest_file_size = reader.GetReadOffset();
-    assert(current_manifest_file_size != 0);
-  }
-
-  if (s.ok()) {
-    if (!version_edit_params.has_next_file_number_) {
-      s = Status::Corruption("no meta-nextfile entry in descriptor");
-    } else if (!version_edit_params.has_log_number_) {
-      s = Status::Corruption("no meta-lognumber entry in descriptor");
-    } else if (!version_edit_params.has_last_sequence_) {
-      s = Status::Corruption("no last-sequence-number entry in descriptor");
-    }
-
-    if (!version_edit_params.has_prev_log_number_) {
-      version_edit_params.SetPrevLogNumber(0);
-    }
-
-    column_family_set_->UpdateMaxColumnFamily(
-        version_edit_params.max_column_family_);
-
-    // When reading DB generated using old release, min_log_number_to_keep=0.
-    // All log files will be scanned for potential prepare entries.
-    MarkMinLogNumberToKeep2PC(version_edit_params.min_log_number_to_keep_);
-    MarkFileNumberUsed(version_edit_params.prev_log_number_);
-    MarkFileNumberUsed(version_edit_params.log_number_);
-  }
-
-  // there were some column families in the MANIFEST that weren't specified
-  // in the argument. This is OK in read_only mode
-  if (read_only == false && !column_families_not_found.empty()) {
-    std::string list_of_not_found;
-    for (const auto& cf : column_families_not_found) {
-      list_of_not_found += ", " + cf.second;
-    }
-    list_of_not_found = list_of_not_found.substr(2);
-    s = Status::InvalidArgument(
-        "You have to open all column families. Column families not opened: " +
-        list_of_not_found);
-  }
-
-  if (s.ok()) {
-    for (auto cfd : *column_family_set_) {
-      assert(builders.count(cfd->GetID()) > 0);
-      auto* builder = builders[cfd->GetID()]->version_builder();
-      if (!builder->CheckConsistencyForNumLevels()) {
-        s = Status::InvalidArgument(
-            "db has more levels than options.num_levels");
-        break;
-      }
+    VersionEditHandler handler(
+        read_only, column_families, const_cast<VersionSet*>(this),
+        /*track_missing_files=*/false,
+        /*no_error_if_table_files_missing=*/false, io_tracer_);
+    handler.Iterate(reader, &log_read_status);
+    s = handler.status();
+    if (s.ok()) {
+      log_number = handler.GetVersionEditParams().log_number_;
+      current_manifest_file_size = reader.GetReadOffset();
+      assert(current_manifest_file_size != 0);
+      handler.GetDbId(db_id);
     }
   }
 
   if (s.ok()) {
-    for (auto cfd : *column_family_set_) {
-      if (cfd->IsDropped()) {
-        continue;
-      }
-      if (read_only) {
-        cfd->table_cache()->SetTablesAreImmortal();
-      }
-      assert(cfd->initialized());
-      auto builders_iter = builders.find(cfd->GetID());
-      assert(builders_iter != builders.end());
-      auto builder = builders_iter->second->version_builder();
-
-      // unlimited table cache. Pre-load table handle now.
-      // Need to do it out of the mutex.
-      s = builder->LoadTableHandlers(
-          cfd->internal_stats(), db_options_->max_file_opening_threads,
-          false /* prefetch_index_and_filter_in_cache */,
-          true /* is_initial_load */,
-          cfd->GetLatestMutableCFOptions()->prefix_extractor.get(),
-          MaxFileSizeForL0MetaPin(*cfd->GetLatestMutableCFOptions()));
-      if (!s.ok()) {
-        if (db_options_->paranoid_checks) {
-          return s;
-        }
-        s = Status::OK();
-      }
-
-      Version* v = new Version(cfd, this, file_options_,
-                               *cfd->GetLatestMutableCFOptions(), io_tracer_,
-                               current_version_number_++);
-      s = builder->SaveTo(v->storage_info());
-      if (!s.ok()) {
-        delete v;
-        return s;
-      }
-
-      // Install recovered version
-      v->PrepareApply(*cfd->GetLatestMutableCFOptions(),
-          !(db_options_->skip_stats_update_on_db_open));
-      AppendVersion(cfd, v);
-    }
-
     manifest_file_size_ = current_manifest_file_size;
-    next_file_number_.store(version_edit_params.next_file_number_ + 1);
-    last_allocated_sequence_ = version_edit_params.last_sequence_;
-    last_published_sequence_ = version_edit_params.last_sequence_;
-    last_sequence_ = version_edit_params.last_sequence_;
-    prev_log_number_ = version_edit_params.prev_log_number_;
-
     ROCKS_LOG_INFO(
         db_options_->info_log,
         "Recovered from manifest file:%s succeeded,"
@@ -4887,9 +4769,8 @@ Status VersionSet::Recover(
         ",prev_log_number is %" PRIu64 ",max_column_family is %" PRIu32
         ",min_log_number_to_keep is %" PRIu64 "\n",
         manifest_path.c_str(), manifest_file_number_, next_file_number_.load(),
-        last_sequence_.load(), version_edit_params.log_number_,
-        prev_log_number_, column_family_set_->GetMaxColumnFamily(),
-        min_log_number_to_keep_2pc());
+        last_sequence_.load(), log_number, prev_log_number_,
+        column_family_set_->GetMaxColumnFamily(), min_log_number_to_keep_2pc());
 
     for (auto cfd : *column_family_set_) {
       if (cfd->IsDropped()) {
@@ -5037,7 +4918,9 @@ Status VersionSet::TryRecoverFromOneManifest(
   VersionEditHandlerPointInTime handler_pit(
       read_only, column_families, const_cast<VersionSet*>(this), io_tracer_);
 
-  handler_pit.Iterate(reader, &s, db_id);
+  handler_pit.Iterate(reader, &s);
+
+  handler_pit.GetDbId(db_id);
 
   assert(nullptr != has_missing_table_file);
   *has_missing_table_file = handler_pit.HasMissingFiles();
@@ -5071,48 +4954,23 @@ Status VersionSet::ListColumnFamilies(std::vector<std::string>* column_families,
                                              nullptr /*IOTracer*/));
   }
 
-  std::map<uint32_t, std::string> column_family_names;
-  // default column family is always implicitly there
-  column_family_names.insert({0, kDefaultColumnFamilyName});
   VersionSet::LogReporter reporter;
   reporter.status = &s;
   log::Reader reader(nullptr, std::move(file_reader), &reporter,
                      true /* checksum */, 0 /* log_number */);
-  Slice record;
-  std::string scratch;
-  while (reader.ReadRecord(&record, &scratch) && s.ok()) {
-    VersionEdit edit;
-    s = edit.DecodeFrom(record);
-    if (!s.ok()) {
-      break;
-    }
-    if (edit.is_column_family_add_) {
-      if (column_family_names.find(edit.column_family_) !=
-          column_family_names.end()) {
-        s = Status::Corruption("Manifest adding the same column family twice");
-        break;
-      }
-      column_family_names.insert(
-          {edit.column_family_, edit.column_family_name_});
-    } else if (edit.is_column_family_drop_) {
-      if (column_family_names.find(edit.column_family_) ==
-          column_family_names.end()) {
-        s = Status::Corruption(
-            "Manifest - dropping non-existing column family");
-        break;
-      }
-      column_family_names.erase(edit.column_family_);
-    }
-  }
 
+  ListColumnFamiliesHandler handler;
+  handler.Iterate(reader, &s);
+
+  assert(column_families);
   column_families->clear();
-  if (s.ok()) {
-    for (const auto& iter : column_family_names) {
+  if (handler.status().ok()) {
+    for (const auto& iter : handler.GetColumnFamilyNames()) {
       column_families->push_back(iter.second);
     }
   }
 
-  return s;
+  return handler.status();
 }
 
 #ifndef ROCKSDB_LITE
@@ -5271,194 +5129,19 @@ Status VersionSet::DumpManifest(Options& options, std::string& dscname,
         std::move(file), dscname, db_options_->log_readahead_size, io_tracer_));
   }
 
-  bool have_prev_log_number = false;
-  bool have_next_file = false;
-  bool have_last_sequence = false;
-  uint64_t next_file = 0;
-  uint64_t last_sequence = 0;
-  uint64_t previous_log_number = 0;
-  int count = 0;
-  std::unordered_map<uint32_t, std::string> comparators;
-  std::unordered_map<uint32_t, std::unique_ptr<BaseReferencedVersionBuilder>>
-      builders;
-
-  // add default column family
-  VersionEdit default_cf_edit;
-  default_cf_edit.AddColumnFamily(kDefaultColumnFamilyName);
-  default_cf_edit.SetColumnFamily(0);
-  ColumnFamilyData* default_cfd =
-      CreateColumnFamily(ColumnFamilyOptions(options), &default_cf_edit);
-  builders.insert(
-      std::make_pair(0, std::unique_ptr<BaseReferencedVersionBuilder>(
-                            new BaseReferencedVersionBuilder(default_cfd))));
-
+  std::vector<ColumnFamilyDescriptor> column_families(
+      1, ColumnFamilyDescriptor(kDefaultColumnFamilyName, options));
+  DumpManifestHandler handler(column_families, this, io_tracer_, verbose, hex,
+                              json);
   {
     VersionSet::LogReporter reporter;
     reporter.status = &s;
     log::Reader reader(nullptr, std::move(file_reader), &reporter,
                        true /* checksum */, 0 /* log_number */);
-    Slice record;
-    std::string scratch;
-    while (reader.ReadRecord(&record, &scratch) && s.ok()) {
-      VersionEdit edit;
-      s = edit.DecodeFrom(record);
-      if (!s.ok()) {
-        break;
-      }
-
-      // Write out each individual edit
-      if (verbose && !json) {
-        printf("%s\n", edit.DebugString(hex).c_str());
-      } else if (json) {
-        printf("%s\n", edit.DebugJSON(count, hex).c_str());
-      }
-      count++;
-
-      bool cf_in_builders =
-          builders.find(edit.column_family_) != builders.end();
-
-      if (edit.has_comparator_) {
-        comparators.insert({edit.column_family_, edit.comparator_});
-      }
-
-      ColumnFamilyData* cfd = nullptr;
-
-      if (edit.is_column_family_add_) {
-        if (cf_in_builders) {
-          s = Status::Corruption(
-              "Manifest adding the same column family twice");
-          break;
-        }
-        cfd = CreateColumnFamily(ColumnFamilyOptions(options), &edit);
-        cfd->set_initialized();
-        builders.insert(std::make_pair(
-            edit.column_family_, std::unique_ptr<BaseReferencedVersionBuilder>(
-                                     new BaseReferencedVersionBuilder(cfd))));
-      } else if (edit.is_column_family_drop_) {
-        if (!cf_in_builders) {
-          s = Status::Corruption(
-              "Manifest - dropping non-existing column family");
-          break;
-        }
-        auto builder_iter = builders.find(edit.column_family_);
-        builders.erase(builder_iter);
-        comparators.erase(edit.column_family_);
-        cfd = column_family_set_->GetColumnFamily(edit.column_family_);
-        assert(cfd != nullptr);
-        cfd->UnrefAndTryDelete();
-        cfd = nullptr;
-      } else {
-        if (!cf_in_builders) {
-          s = Status::Corruption(
-              "Manifest record referencing unknown column family");
-          break;
-        }
-
-        cfd = column_family_set_->GetColumnFamily(edit.column_family_);
-        // this should never happen since cf_in_builders is true
-        assert(cfd != nullptr);
-
-        // if it is not column family add or column family drop,
-        // then it's a file add/delete, which should be forwarded
-        // to builder
-        auto builder = builders.find(edit.column_family_);
-        assert(builder != builders.end());
-        s = builder->second->version_builder()->Apply(&edit);
-        if (!s.ok()) {
-          break;
-        }
-      }
-
-      if (cfd != nullptr && edit.has_log_number_) {
-        cfd->SetLogNumber(edit.log_number_);
-      }
-
-
-      if (edit.has_prev_log_number_) {
-        previous_log_number = edit.prev_log_number_;
-        have_prev_log_number = true;
-      }
-
-      if (edit.has_next_file_number_) {
-        next_file = edit.next_file_number_;
-        have_next_file = true;
-      }
-
-      if (edit.has_last_sequence_) {
-        last_sequence = edit.last_sequence_;
-        have_last_sequence = true;
-      }
-
-      if (edit.has_max_column_family_) {
-        column_family_set_->UpdateMaxColumnFamily(edit.max_column_family_);
-      }
-
-      if (edit.has_min_log_number_to_keep_) {
-        MarkMinLogNumberToKeep2PC(edit.min_log_number_to_keep_);
-      }
-    }
-  }
-  file_reader.reset();
-
-  if (s.ok()) {
-    if (!have_next_file) {
-      s = Status::Corruption("no meta-nextfile entry in descriptor");
-      printf("no meta-nextfile entry in descriptor");
-    } else if (!have_last_sequence) {
-      printf("no last-sequence-number entry in descriptor");
-      s = Status::Corruption("no last-sequence-number entry in descriptor");
-    }
-
-    if (!have_prev_log_number) {
-      previous_log_number = 0;
-    }
+    handler.Iterate(reader, &s);
   }
 
-  if (s.ok()) {
-    for (auto cfd : *column_family_set_) {
-      if (cfd->IsDropped()) {
-        continue;
-      }
-      auto builders_iter = builders.find(cfd->GetID());
-      assert(builders_iter != builders.end());
-      auto builder = builders_iter->second->version_builder();
-
-      Version* v = new Version(cfd, this, file_options_,
-                               *cfd->GetLatestMutableCFOptions(), io_tracer_,
-                               current_version_number_++);
-      s = builder->SaveTo(v->storage_info());
-      v->PrepareApply(*cfd->GetLatestMutableCFOptions(), false);
-
-      printf("--------------- Column family \"%s\"  (ID %" PRIu32
-             ") --------------\n",
-             cfd->GetName().c_str(), cfd->GetID());
-      printf("log number: %" PRIu64 "\n", cfd->GetLogNumber());
-      auto comparator = comparators.find(cfd->GetID());
-      if (comparator != comparators.end()) {
-        printf("comparator: %s\n", comparator->second.c_str());
-      } else {
-        printf("comparator: <NO COMPARATOR>\n");
-      }
-      printf("%s \n", v->DebugString(hex).c_str());
-      delete v;
-    }
-
-    next_file_number_.store(next_file + 1);
-    last_allocated_sequence_ = last_sequence;
-    last_published_sequence_ = last_sequence;
-    last_sequence_ = last_sequence;
-    prev_log_number_ = previous_log_number;
-
-    printf("next_file_number %" PRIu64 " last_sequence %" PRIu64
-           "  prev_log_number %" PRIu64 " max_column_family %" PRIu32
-           " min_log_number_to_keep "
-           "%" PRIu64 "\n",
-           next_file_number_.load(), last_sequence, previous_log_number,
-           column_family_set_->GetMaxColumnFamily(),
-           min_log_number_to_keep_2pc());
-  }
-
-  return s;
+  return handler.status();
 }
 #endif  // ROCKSDB_LITE
 

db/version_set.h

@@ -1227,6 +1227,7 @@ class VersionSet {
   friend class Version;
   friend class VersionEditHandler;
   friend class VersionEditHandlerPointInTime;
+  friend class DumpManifestHandler;
   friend class DBImpl;
   friend class DBImplReadOnly;
 

db/version_set_test.cc

@@ -1750,6 +1750,10 @@ class VersionSetAtomicGroupTest : public VersionSetTestBase,
           EXPECT_TRUE(first_in_atomic_group_);
           last_in_atomic_group_ = true;
         });
+    SyncPoint::GetInstance()->SetCallBack(
+        "VersionEditHandlerBase::Iterate:Finish", [&](void* arg) {
+          num_recovered_edits_ = *reinterpret_cast<int*>(arg);
+        });
     SyncPoint::GetInstance()->SetCallBack(
         "VersionSet::ReadAndRecover:RecoveredEdits", [&](void* arg) {
           num_recovered_edits_ = *reinterpret_cast<int*>(arg);

util/file_checksum_helper.cc

@@ -13,6 +13,7 @@
 
 #include "db/log_reader.h"
 #include "db/version_edit.h"
+#include "db/version_edit_handler.h"
 #include "file/sequence_file_reader.h"
 
 namespace ROCKSDB_NAMESPACE {
@@ -95,7 +96,7 @@ Status GetFileChecksumsFromManifest(Env* src_env, const std::string& abs_path,
   if (checksum_list == nullptr) {
     return Status::InvalidArgument("checksum_list is nullptr");
   }
-
+  assert(checksum_list);
   checksum_list->reset();
   Status s;
 
@@ -123,32 +124,13 @@ Status GetFileChecksumsFromManifest(Env* src_env, const std::string& abs_path,
   reporter.status_ptr = &s;
   log::Reader reader(nullptr, std::move(file_reader), &reporter,
                      true /* checksum */, 0 /* log_number */);
-  Slice record;
-  std::string scratch;
-  while (reader.LastRecordEnd() < manifest_file_size &&
-         reader.ReadRecord(&record, &scratch) && s.ok()) {
-    VersionEdit edit;
-    s = edit.DecodeFrom(record);
-    if (!s.ok()) {
-      break;
-    }
-
-    // Remove the deleted files from the checksum_list
-    for (const auto& deleted_file : edit.GetDeletedFiles()) {
-      checksum_list->RemoveOneFileChecksum(deleted_file.second);
-    }
-
-    // Add the new files to the checksum_list
-    for (const auto& new_file : edit.GetNewFiles()) {
-      checksum_list->InsertOneFileChecksum(
-          new_file.second.fd.GetNumber(), new_file.second.file_checksum,
-          new_file.second.file_checksum_func_name);
-    }
-  }
-  assert(!s.ok() ||
+  FileChecksumRetriever retriever(manifest_file_size, *checksum_list);
+  retriever.Iterate(reader, &s);
+  assert(!retriever.status().ok() ||
          manifest_file_size == std::numeric_limits<uint64_t>::max() ||
          reader.LastRecordEnd() == manifest_file_size);
-  return s;
+
+  return retriever.status();
 }
 
 }  // namespace ROCKSDB_NAMESPACE