CF cleanup part 2

db/version_set.cc

@@ -1489,12 +1489,11 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
                                const ColumnFamilyOptions* options) {
   mu->AssertHeld();
 
-  assert(column_family_data != nullptr || edit->is_column_family_add_);
-
-  if (edit->is_column_family_drop_) {
-    // if we drop column family, we have to make sure to save max column family,
-    // so that we don't reuse existing ID
-    edit->SetMaxColumnFamily(column_family_set_->GetMaxColumnFamily());
+  // column_family_data can be nullptr only if this is column_family_add.
+  // in that case, we also need to specify ColumnFamilyOptions
+  if (column_family_data == nullptr) {
+    assert(edit->is_column_family_add_);
+    assert(options != nullptr);
   }
 
   // queue our request
@@ -1527,9 +1526,7 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
   assert(manifest_writers_.front() == &w);
   if (edit->IsColumnFamilyManipulation()) {
     // no group commits for column family add or drop
-    last_writer = &w;
-    edit->SetNextFile(next_file_number_);
-    edit->SetLastSequence(last_sequence_);
+    LogAndApplyCFHelper(edit);
     batch_edits.push_back(edit);
   } else {
     v = new Version(column_family_data, this, current_version_number_++);
@@ -1567,6 +1564,11 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
   if (new_descriptor_log) {
     new_manifest_filename = DescriptorFileName(dbname_, manifest_file_number_);
     edit->SetNextFile(next_file_number_);
+    // if we're writing out new snapshot make sure to persist max column
+    // family
+    if (column_family_set_->GetMaxColumnFamily() > 0) {
+      edit->SetMaxColumnFamily(column_family_set_->GetMaxColumnFamily());
+    }
   }
 
   // Unlock during expensive operations. New writes cannot get here
@@ -1590,7 +1592,7 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
 
     // This is fine because everything inside of this block is serialized --
     // only one thread can be here at the same time
-    if (!new_manifest_filename.empty()) {
+    if (new_descriptor_log) {
       unique_ptr<WritableFile> descriptor_file;
       s = env_->NewWritableFile(new_manifest_filename, &descriptor_file,
                                 storage_options_.AdaptForLogWrite());
@@ -1725,16 +1727,22 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
   return s;
 }
 
+void VersionSet::LogAndApplyCFHelper(VersionEdit* edit) {
+  assert(edit->IsColumnFamilyManipulation());
+  edit->SetNextFile(next_file_number_);
+  edit->SetLastSequence(last_sequence_);
+  if (edit->is_column_family_drop_) {
+    // if we drop column family, we have to make sure to save max column family,
+    // so that we don't reuse existing ID
+    edit->SetMaxColumnFamily(column_family_set_->GetMaxColumnFamily());
+  }
+}
+
 void VersionSet::LogAndApplyHelper(ColumnFamilyData* cfd, Builder* builder,
                                    Version* v, VersionEdit* edit,
                                    port::Mutex* mu) {
   mu->AssertHeld();
-
-  if (!edit->has_prev_log_number_) {
-    edit->SetPrevLogNumber(prev_log_number_);
-  }
-  edit->SetNextFile(next_file_number_);
-  edit->SetLastSequence(last_sequence_);
+  assert(!edit->IsColumnFamilyManipulation());
 
   if (edit->has_log_number_) {
     assert(edit->log_number_ >= cfd->GetLogNumber());
@@ -1743,6 +1751,12 @@ void VersionSet::LogAndApplyHelper(ColumnFamilyData* cfd, Builder* builder,
   }
   assert(edit->log_number_ < next_file_number_);
 
+  if (!edit->has_prev_log_number_) {
+    edit->SetPrevLogNumber(prev_log_number_);
+  }
+  edit->SetNextFile(next_file_number_);
+  edit->SetLastSequence(last_sequence_);
+
   builder->Apply(edit);
 }
 
@@ -1806,17 +1820,16 @@ Status VersionSet::Recover(
   std::unordered_map<uint32_t, Builder*> builders;
 
   // add default column family
-  VersionEdit default_cf_edit;
-  default_cf_edit.AddColumnFamily(default_column_family_name);
-  default_cf_edit.SetColumnFamily(0);
   auto default_cf_iter = cf_name_to_options.find(default_column_family_name);
   if (default_cf_iter == cf_name_to_options.end()) {
-    column_families_not_found.insert(0);
-  } else {
-    ColumnFamilyData* default_cfd =
-        CreateColumnFamily(default_cf_iter->second, &default_cf_edit);
-    builders.insert({0, new Builder(default_cfd)});
+    return Status::InvalidArgument("Default column family not specified");
   }
+  VersionEdit default_cf_edit;
+  default_cf_edit.AddColumnFamily(default_column_family_name);
+  default_cf_edit.SetColumnFamily(0);
+  ColumnFamilyData* default_cfd =
+      CreateColumnFamily(default_cf_iter->second, &default_cf_edit);
+  builders.insert({0, new Builder(default_cfd)});
 
   {
     VersionSet::LogReporter reporter;
@@ -2357,9 +2370,11 @@ void VersionSet::MarkFileNumberUsed(uint64_t number) {
 Status VersionSet::WriteSnapshot(log::Writer* log) {
   // TODO: Break up into multiple records to reduce memory usage on recovery?
 
+  // WARNING: This method doesn't hold a mutex!!
+
   // This is done without DB mutex lock held, but only within single-threaded
   // LogAndApply. Column family manipulations can only happen within LogAndApply
-  // (the same single thread), so we're safe
+  // (the same single thread), so we're safe to iterate.
   for (auto cfd : *column_family_set_) {
     {
       // Store column family info
@@ -2406,18 +2421,7 @@ Status VersionSet::WriteSnapshot(log::Writer* log) {
     }
   }
 
-  {
-    // persist max column family, last sequence and next file
-    VersionEdit edit;
-    if (column_family_set_->GetMaxColumnFamily() > 0) {
-      edit.SetMaxColumnFamily(column_family_set_->GetMaxColumnFamily());
-    }
-    edit.SetLastSequence(last_sequence_);
-    edit.SetNextFile(next_file_number_);
-    std::string record;
-    edit.EncodeTo(&record);
-    return log->AddRecord(record);
-  }
+  return Status::OK();
 }
 
 // Opens the mainfest file and reads all records

db/version_set.h

@@ -466,6 +466,7 @@ class VersionSet {
   VersionSet(const VersionSet&);
   void operator=(const VersionSet&);
 
+  void LogAndApplyCFHelper(VersionEdit* edit);
   void LogAndApplyHelper(ColumnFamilyData* cfd, Builder* b, Version* v,
                          VersionEdit* edit, port::Mutex* mu);
 };

db/write_batch.cc

@@ -177,7 +177,6 @@ void WriteBatch::Put(uint32_t column_family_id, const Slice& key,
                      const Slice& value) {
   WriteBatchInternal::SetCount(this, WriteBatchInternal::Count(this) + 1);
   if (column_family_id == 0) {
-    // save some data on disk by not writing default column family
     rep_.push_back(static_cast<char>(kTypeValue));
   } else {
     rep_.push_back(static_cast<char>(kTypeColumnFamilyValue));