Avoid calling GetDBOptions() inside GetFromBatchAndDB()

Summary:
MyRocks hit a regression, @mung generated perf reports showing that the reason is the cost of calling `GetDBOptions()` inside `GetFromBatchAndDB()`
This diff avoid calling `GetDBOptions` and use the `ImmutableDBOptions` instead

Test Plan: make check -j64

Reviewers: sdong, yiwu

Reviewed By: yiwu

Subscribers: andrewkr, dhruba, mung

Differential Revision: https://reviews.facebook.net/D65151

db/db_impl.h

@@ -396,6 +396,10 @@ class DBImpl : public DB {
 
   const SnapshotList& snapshots() const { return snapshots_; }
 
+  const ImmutableDBOptions& immutable_db_options() const {
+    return immutable_db_options_;
+  }
+
   void CancelAllBackgroundWork(bool wait);
 
   // Find Super version and reference it. Based on options, it might return

utilities/write_batch_with_index/write_batch_with_index.cc

@@ -11,12 +11,14 @@
 #include <memory>
 
 #include "db/column_family.h"
+#include "db/db_impl.h"
 #include "db/merge_context.h"
 #include "db/merge_helper.h"
 #include "db/skiplist.h"
 #include "rocksdb/comparator.h"
 #include "rocksdb/iterator.h"
 #include "util/arena.h"
+#include "util/db_options.h"
 #include "utilities/write_batch_with_index/write_batch_with_index_internal.h"
 
 namespace rocksdb {
@@ -680,11 +682,12 @@ Status WriteBatchWithIndex::GetFromBatch(ColumnFamilyHandle* column_family,
                                          const Slice& key, std::string* value) {
   Status s;
   MergeContext merge_context;
+  const ImmutableDBOptions immuable_db_options(options);
 
   WriteBatchWithIndexInternal::Result result =
       WriteBatchWithIndexInternal::GetFromBatch(
-          options, this, column_family, key, &merge_context, &rep->comparator,
-          value, rep->overwrite_key, &s);
+          immuable_db_options, this, column_family, key, &merge_context,
+          &rep->comparator, value, rep->overwrite_key, &s);
 
   switch (result) {
     case WriteBatchWithIndexInternal::Result::kFound:
@@ -720,13 +723,14 @@ Status WriteBatchWithIndex::GetFromBatchAndDB(DB* db,
                                               std::string* value) {
   Status s;
   MergeContext merge_context;
-  const DBOptions& options = db->GetDBOptions();
+  const ImmutableDBOptions& immuable_db_options =
+      reinterpret_cast<DBImpl*>(db)->immutable_db_options();
 
   std::string batch_value;
   WriteBatchWithIndexInternal::Result result =
       WriteBatchWithIndexInternal::GetFromBatch(
-          options, this, column_family, key, &merge_context, &rep->comparator,
-          &batch_value, rep->overwrite_key, &s);
+          immuable_db_options, this, column_family, key, &merge_context,
+          &rep->comparator, &batch_value, rep->overwrite_key, &s);
 
   if (result == WriteBatchWithIndexInternal::Result::kFound) {
     value->assign(batch_value.data(), batch_value.size());
@@ -758,9 +762,9 @@ Status WriteBatchWithIndex::GetFromBatchAndDB(DB* db,
       auto cfh = reinterpret_cast<ColumnFamilyHandleImpl*>(column_family);
       const MergeOperator* merge_operator =
           cfh->cfd()->ioptions()->merge_operator;
-      Statistics* statistics = options.statistics.get();
-      Env* env = options.env;
-      Logger* logger = options.info_log.get();
+      Statistics* statistics = immuable_db_options.statistics.get();
+      Env* env = immuable_db_options.env;
+      Logger* logger = immuable_db_options.info_log.get();
 
       Slice db_slice(*value);
       Slice* merge_data;

utilities/write_batch_with_index/write_batch_with_index_internal.cc

@@ -133,7 +133,7 @@ int WriteBatchEntryComparator::CompareKey(uint32_t column_family,
 }
 
 WriteBatchWithIndexInternal::Result WriteBatchWithIndexInternal::GetFromBatch(
-    const DBOptions& options, WriteBatchWithIndex* batch,
+    const ImmutableDBOptions& immuable_db_options, WriteBatchWithIndex* batch,
     ColumnFamilyHandle* column_family, const Slice& key,
     MergeContext* merge_context, WriteBatchEntryComparator* cmp,
     std::string* value, bool overwrite_key, Status* s) {
@@ -237,9 +237,9 @@ WriteBatchWithIndexInternal::Result WriteBatchWithIndexInternal::GetFromBatch(
           result = WriteBatchWithIndexInternal::Result::kError;
           return result;
         }
-        Statistics* statistics = options.statistics.get();
-        Env* env = options.env;
-        Logger* logger = options.info_log.get();
+        Statistics* statistics = immuable_db_options.statistics.get();
+        Env* env = immuable_db_options.env;
+        Logger* logger = immuable_db_options.info_log.get();
 
         if (merge_operator) {
           *s = MergeHelper::TimedFullMerge(merge_operator, key, entry_value,

utilities/write_batch_with_index/write_batch_with_index_internal.h

@@ -10,12 +10,13 @@
 #include <string>
 #include <vector>
 
+#include "port/port.h"
 #include "rocksdb/comparator.h"
 #include "rocksdb/iterator.h"
 #include "rocksdb/slice.h"
 #include "rocksdb/status.h"
 #include "rocksdb/utilities/write_batch_with_index.h"
-#include "port/port.h"
+#include "util/db_options.h"
 
 namespace rocksdb {
 
@@ -103,7 +104,7 @@ class WriteBatchWithIndexInternal {
   // If batch does not contain this key, return kNotFound
   // Else, return kError on error with error Status stored in *s.
   static WriteBatchWithIndexInternal::Result GetFromBatch(
-      const DBOptions& options, WriteBatchWithIndex* batch,
+      const ImmutableDBOptions& ioptions, WriteBatchWithIndex* batch,
       ColumnFamilyHandle* column_family, const Slice& key,
       MergeContext* merge_context, WriteBatchEntryComparator* cmp,
       std::string* value, bool overwrite_key, Status* s);