max_open_files dynamic set, follow up

Summary:
Followup to make 0x40000 a TableCache constant that indicates infinite capacity
Closes https://github.com/facebook/rocksdb/pull/2247

Differential Revision: D5001349

Pulled By: lgalanis

fbshipit-source-id: ce7bd2e54b0975bb9f8680fdaa0f8bb0e7ae81a2

HISTORY.md

@@ -5,7 +5,6 @@
 
 ### New Features
 * DB::ResetStats() to reset internal stats.
-* Support dynamically change `max_open_files` option via SetDBOptions()
 * Statistics::Reset() to reset user stats.
 * ldb add option --try_load_options, which will open DB with its own option file.
 * Support dynamically change `max_open_files` option via SetDBOptions()

db/db_impl.cc

@@ -193,7 +193,7 @@ DBImpl::DBImpl(const DBOptions& options, const std::string& dbname)
   // Reserve ten files or so for other uses and give the rest to TableCache.
   // Give a large number for setting of "infinite" open files.
   const int table_cache_size = (mutable_db_options_.max_open_files == -1)
-                                   ? 0x400000
+                                   ? TableCache::kInfiniteCapacity
                                    : mutable_db_options_.max_open_files - 10;
   table_cache_ = NewLRUCache(table_cache_size,
                              immutable_db_options_.table_cache_numshardbits);
@@ -582,7 +582,7 @@ Status DBImpl::SetDBOptions(
 
       write_controller_.set_max_delayed_write_rate(new_options.delayed_write_rate);
       table_cache_.get()->SetCapacity(new_options.max_open_files == -1
-                                          ? 0x400000
+                                          ? TableCache::kInfiniteCapacity
                                           : new_options.max_open_files - 10);
 
       mutable_db_options_ = new_options;

db/table_cache.h

@@ -117,6 +117,10 @@ class TableCache {
   // Release the handle from a cache
   void ReleaseHandle(Cache::Handle* handle);
 
+  // Capacity of the backing Cache that indicates inifinite TableCache capacity.
+  // For example when max_open_files is -1 we set the backing Cache to this.
+  static const int kInfiniteCapacity = 0x400000;
+
  private:
   // Build a table reader
   Status GetTableReader(const EnvOptions& env_options,

db/version_set.cc

@@ -1123,9 +1123,9 @@ void Version::UpdateAccumulatedStats(bool update_stats) {
           // already been read, so MaybeInitializeFileMetaData() won't incur
           // any I/O cost. "max_open_files=-1" means that the table cache passed
           // to the VersionSet and then to the ColumnFamilySet has a size of
-          // 0x400000
+          // TableCache::kInfiniteCapacity
           if (vset_->GetColumnFamilySet()->get_table_cache()->GetCapacity() ==
-              0x400000) {
+              TableCache::kInfiniteCapacity) {
             continue;
           }
           if (++init_count >= kMaxInitCount) {
@@ -2384,7 +2384,7 @@ Status VersionSet::LogAndApply(ColumnFamilyData* column_family_data,
     TEST_SYNC_POINT("VersionSet::LogAndApply:WriteManifest");
     if (!w.edit_list.front()->IsColumnFamilyManipulation() &&
         this->GetColumnFamilySet()->get_table_cache()->GetCapacity() ==
-            0x400000) {
+            TableCache::kInfiniteCapacity) {
       // unlimited table cache. Pre-load table handle now.
       // Need to do it out of the mutex.
       builder_guard->version_builder()->LoadTableHandlers(
@@ -2830,7 +2830,8 @@ Status VersionSet::Recover(
       assert(builders_iter != builders.end());
       auto* builder = builders_iter->second->version_builder();
 
-      if (GetColumnFamilySet()->get_table_cache()->GetCapacity() == 0x400000) {
+      if (GetColumnFamilySet()->get_table_cache()->GetCapacity() ==
+          TableCache::kInfiniteCapacity) {
         // unlimited table cache. Pre-load table handle now.
         // Need to do it out of the mutex.
         builder->LoadTableHandlers(