Remove function from DBImpl that are not used anywhere

Summary:
GetAndRefSuperVersionUnlocked
ReturnAndCleanupSuperVersionUnlocked
GetColumnFamilyHandleUnlocked

Are dead code that are not used any where
Closes https://github.com/facebook/rocksdb/pull/1802

Differential Revision: D4459948

Pulled By: IslamAbdelRahman

fbshipit-source-id: 30fa89d

db/db_impl.cc

@@ -5493,22 +5493,6 @@ SuperVersion* DBImpl::GetAndRefSuperVersion(uint32_t column_family_id) {
   return GetAndRefSuperVersion(cfd);
 }
 
-// REQUIRED:  mutex is NOT held
-SuperVersion* DBImpl::GetAndRefSuperVersionUnlocked(uint32_t column_family_id) {
-  ColumnFamilyData* cfd;
-  {
-    InstrumentedMutexLock l(&mutex_);
-    auto column_family_set = versions_->GetColumnFamilySet();
-    cfd = column_family_set->GetColumnFamily(column_family_id);
-  }
-
-  if (!cfd) {
-    return nullptr;
-  }
-
-  return GetAndRefSuperVersion(cfd);
-}
-
 void DBImpl::ReturnAndCleanupSuperVersion(ColumnFamilyData* cfd,
                                           SuperVersion* sv) {
   bool unref_sv = !cfd->ReturnThreadLocalSuperVersion(sv);
@@ -5539,22 +5523,6 @@ void DBImpl::ReturnAndCleanupSuperVersion(uint32_t column_family_id,
   ReturnAndCleanupSuperVersion(cfd, sv);
 }
 
-// REQUIRED: Mutex should NOT be held.
-void DBImpl::ReturnAndCleanupSuperVersionUnlocked(uint32_t column_family_id,
-                                                  SuperVersion* sv) {
-  ColumnFamilyData* cfd;
-  {
-    InstrumentedMutexLock l(&mutex_);
-    auto column_family_set = versions_->GetColumnFamilySet();
-    cfd = column_family_set->GetColumnFamily(column_family_id);
-  }
-
-  // If SuperVersion is held, and we successfully fetched a cfd using
-  // GetAndRefSuperVersion(), it must still exist.
-  assert(cfd != nullptr);
-  ReturnAndCleanupSuperVersion(cfd, sv);
-}
-
 // REQUIRED: this function should only be called on the write thread or if the
 // mutex is held.
 ColumnFamilyHandle* DBImpl::GetColumnFamilyHandle(uint32_t column_family_id) {
@@ -5567,20 +5535,6 @@ ColumnFamilyHandle* DBImpl::GetColumnFamilyHandle(uint32_t column_family_id) {
   return cf_memtables->GetColumnFamilyHandle();
 }
 
-// REQUIRED: mutex is NOT held.
-ColumnFamilyHandle* DBImpl::GetColumnFamilyHandleUnlocked(
-    uint32_t column_family_id) {
-  ColumnFamilyMemTables* cf_memtables = column_family_memtables_.get();
-
-  InstrumentedMutexLock l(&mutex_);
-
-  if (!cf_memtables->Seek(column_family_id)) {
-    return nullptr;
-  }
-
-  return cf_memtables->GetColumnFamilyHandle();
-}
-
 void DBImpl::GetApproximateSizes(ColumnFamilyHandle* column_family,
                                  const Range* range, int n, uint64_t* sizes,
                                  uint8_t include_flags) {

db/db_impl.h

@@ -431,9 +431,6 @@ class DBImpl : public DB {
   // mutex is held.
   SuperVersion* GetAndRefSuperVersion(uint32_t column_family_id);
 
-  // Same as above, should called without mutex held and not on write thread.
-  SuperVersion* GetAndRefSuperVersionUnlocked(uint32_t column_family_id);
-
   // Un-reference the super version and return it to thread local cache if
   // needed. If it is the last reference of the super version. Clean it up
   // after un-referencing it.
@@ -444,18 +441,11 @@ class DBImpl : public DB {
   // REQUIRED: this function should only be called on the write thread.
   void ReturnAndCleanupSuperVersion(uint32_t colun_family_id, SuperVersion* sv);
 
-  // Same as above, should called without mutex held and not on write thread.
-  void ReturnAndCleanupSuperVersionUnlocked(uint32_t colun_family_id,
-                                            SuperVersion* sv);
-
   // REQUIRED: this function should only be called on the write thread or if the
   // mutex is held.  Return value only valid until next call to this function or
   // mutex is released.
   ColumnFamilyHandle* GetColumnFamilyHandle(uint32_t column_family_id);
 
-  // Same as above, should called without mutex held and not on write thread.
-  ColumnFamilyHandle* GetColumnFamilyHandleUnlocked(uint32_t column_family_id);
-
   // Returns the number of currently running flushes.
   // REQUIREMENT: mutex_ must be held when calling this function.
   int num_running_flushes() {