Remove unused variable single_column_family_mode_ (#10078)

Summary: This variable is actually not being used for anything meaningful, thus remove it. This can make #7516 slightly simpler by reducing the amount of state that must be made lock-free. Pull Request resolved: #10078 Test Plan: make check Reviewed By: ajkr Differential Revision: D36779817 Pulled By: riversand963 fbshipit-source-id: ffb0d9ad6149616917ae5e02bb28102cb90fc406
facebook · May 31, 2022 · 7c8c803 · 7c8c803
1 parent 151dc00
commit 7c8c803
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Showing 5 changed files with 12 additions and 16 deletions.
diff --git a/db/db_impl/db_impl.cc b/db/db_impl/db_impl.cc
@@ -2772,7 +2772,6 @@ Status DBImpl::CreateColumnFamilyImpl(const ColumnFamilyOptions& cf_options,
       s = cfd->AddDirectories(&dummy_created_dirs);
     }
     if (s.ok()) {
-      single_column_family_mode_ = false;
       auto* cfd =
           versions_->GetColumnFamilySet()->GetColumnFamily(column_family_name);
       assert(cfd != nullptr);

diff --git a/db/db_impl/db_impl.h b/db/db_impl/db_impl.h
@@ -1207,9 +1207,6 @@ class DBImpl : public DB {
   // only used for dynamically adjusting max_total_wal_size. it is a sum of
   // [write_buffer_size * max_write_buffer_number] over all column families
   uint64_t max_total_in_memory_state_;
-  // If true, we have only one (default) column family. We use this to optimize
-  // some code-paths
-  bool single_column_family_mode_;
 
   // The options to access storage files
   const FileOptions file_options_;

diff --git a/db/db_impl/db_impl_open.cc b/db/db_impl/db_impl_open.cc
@@ -561,10 +561,6 @@ Status DBImpl::Recover(
     default_cf_handle_ = new ColumnFamilyHandleImpl(
         versions_->GetColumnFamilySet()->GetDefault(), this, &mutex_);
     default_cf_internal_stats_ = default_cf_handle_->cfd()->internal_stats();
-    // TODO(Zhongyi): handle single_column_family_mode_ when
-    // persistent_stats is enabled
-    single_column_family_mode_ =
-        versions_->GetColumnFamilySet()->NumberOfColumnFamilies() == 1;
 
     // Recover from all newer log files than the ones named in the
     // descriptor (new log files may have been added by the previous

diff --git a/db/db_impl/db_impl_secondary.cc b/db/db_impl/db_impl_secondary.cc
@@ -61,8 +61,6 @@ Status DBImplSecondary::Recover(
     default_cf_handle_ = new ColumnFamilyHandleImpl(
         versions_->GetColumnFamilySet()->GetDefault(), this, &mutex_);
     default_cf_internal_stats_ = default_cf_handle_->cfd()->internal_stats();
-    single_column_family_mode_ =
-        versions_->GetColumnFamilySet()->NumberOfColumnFamilies() == 1;
 
     std::unordered_set<ColumnFamilyData*> cfds_changed;
     s = FindAndRecoverLogFiles(&cfds_changed, &job_context);

diff --git a/db/db_impl/db_impl_write.cc b/db/db_impl/db_impl_write.cc
@@ -1041,12 +1041,18 @@ Status DBImpl::PreprocessWrite(const WriteOptions& write_options,
 
   PERF_TIMER_GUARD(write_scheduling_flushes_compactions_time);
 
-  assert(!single_column_family_mode_ ||
-         versions_->GetColumnFamilySet()->NumberOfColumnFamilies() == 1);
-  if (UNLIKELY(status.ok() && !single_column_family_mode_ &&
-               total_log_size_ > GetMaxTotalWalSize())) {
-    WaitForPendingWrites();
-    status = SwitchWAL(write_context);
+  if (UNLIKELY(status.ok() && total_log_size_ > GetMaxTotalWalSize())) {
+    assert(versions_);
+    const ColumnFamilySet* const column_families =
+        versions_->GetColumnFamilySet();
+    assert(column_families);
+    size_t num_cfs = column_families->NumberOfColumnFamilies();
+
+    assert(num_cfs >= 1);
+    if (num_cfs > 1) {
+      WaitForPendingWrites();
+      status = SwitchWAL(write_context);
+    }
   }
 
   if (UNLIKELY(status.ok() && write_buffer_manager_->ShouldFlush())) {