Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 753 insertions, 0 deletions

diff --git a/src/rocksdb/db/table_cache.cc b/src/rocksdb/db/table_cache.cc
new file mode 100644
index 000000000..c44c4bb84
--- /dev/null
+++ b/src/rocksdb/db/table_cache.cc
@@ -0,0 +1,753 @@
+//  Copyright (c) 2011-present, Facebook, Inc.  All rights reserved.
+//  This source code is licensed under both the GPLv2 (found in the
+//  COPYING file in the root directory) and Apache 2.0 License
+//  (found in the LICENSE.Apache file in the root directory).
+//
+// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file. See the AUTHORS file for names of contributors.
+
+#include "db/table_cache.h"
+
+#include "db/dbformat.h"
+#include "db/range_tombstone_fragmenter.h"
+#include "db/snapshot_impl.h"
+#include "db/version_edit.h"
+#include "file/file_util.h"
+#include "file/filename.h"
+#include "file/random_access_file_reader.h"
+#include "monitoring/perf_context_imp.h"
+#include "rocksdb/advanced_options.h"
+#include "rocksdb/statistics.h"
+#include "table/block_based/block_based_table_reader.h"
+#include "table/get_context.h"
+#include "table/internal_iterator.h"
+#include "table/iterator_wrapper.h"
+#include "table/multiget_context.h"
+#include "table/table_builder.h"
+#include "table/table_reader.h"
+#include "test_util/sync_point.h"
+#include "util/cast_util.h"
+#include "util/coding.h"
+#include "util/stop_watch.h"
+
+namespace ROCKSDB_NAMESPACE {
+namespace {
+template <class T>
+static void DeleteEntry(const Slice& /*key*/, void* value) {
+  T* typed_value = reinterpret_cast<T*>(value);
+  delete typed_value;
+}
+}  // anonymous namespace
+}  // namespace ROCKSDB_NAMESPACE
+
+// Generate the regular and coroutine versions of some methods by
+// including table_cache_sync_and_async.h twice
+// Macros in the header will expand differently based on whether
+// WITH_COROUTINES or WITHOUT_COROUTINES is defined
+// clang-format off
+#define WITHOUT_COROUTINES
+#include "db/table_cache_sync_and_async.h"
+#undef WITHOUT_COROUTINES
+#define WITH_COROUTINES
+#include "db/table_cache_sync_and_async.h"
+#undef WITH_COROUTINES
+// clang-format on
+
+namespace ROCKSDB_NAMESPACE {
+
+namespace {
+
+static void UnrefEntry(void* arg1, void* arg2) {
+  Cache* cache = reinterpret_cast<Cache*>(arg1);
+  Cache::Handle* h = reinterpret_cast<Cache::Handle*>(arg2);
+  cache->Release(h);
+}
+
+static Slice GetSliceForFileNumber(const uint64_t* file_number) {
+  return Slice(reinterpret_cast<const char*>(file_number),
+               sizeof(*file_number));
+}
+
+#ifndef ROCKSDB_LITE
+
+void AppendVarint64(IterKey* key, uint64_t v) {
+  char buf[10];
+  auto ptr = EncodeVarint64(buf, v);
+  key->TrimAppend(key->Size(), buf, ptr - buf);
+}
+
+#endif  // ROCKSDB_LITE
+
+}  // anonymous namespace
+
+const int kLoadConcurency = 128;
+
+TableCache::TableCache(const ImmutableOptions& ioptions,
+                       const FileOptions* file_options, Cache* const cache,
+                       BlockCacheTracer* const block_cache_tracer,
+                       const std::shared_ptr<IOTracer>& io_tracer,
+                       const std::string& db_session_id)
+    : ioptions_(ioptions),
+      file_options_(*file_options),
+      cache_(cache),
+      immortal_tables_(false),
+      block_cache_tracer_(block_cache_tracer),
+      loader_mutex_(kLoadConcurency, kGetSliceNPHash64UnseededFnPtr),
+      io_tracer_(io_tracer),
+      db_session_id_(db_session_id) {
+  if (ioptions_.row_cache) {
+    // If the same cache is shared by multiple instances, we need to
+    // disambiguate its entries.
+    PutVarint64(&row_cache_id_, ioptions_.row_cache->NewId());
+  }
+}
+
+TableCache::~TableCache() {}
+
+TableReader* TableCache::GetTableReaderFromHandle(Cache::Handle* handle) {
+  return reinterpret_cast<TableReader*>(cache_->Value(handle));
+}
+
+void TableCache::ReleaseHandle(Cache::Handle* handle) {
+  cache_->Release(handle);
+}
+
+Status TableCache::GetTableReader(
+    const ReadOptions& ro, const FileOptions& file_options,
+    const InternalKeyComparator& internal_comparator,
+    const FileMetaData& file_meta, bool sequential_mode, bool record_read_stats,
+    HistogramImpl* file_read_hist, std::unique_ptr<TableReader>* table_reader,
+    const std::shared_ptr<const SliceTransform>& prefix_extractor,
+    bool skip_filters, int level, bool prefetch_index_and_filter_in_cache,
+    size_t max_file_size_for_l0_meta_pin, Temperature file_temperature) {
+  std::string fname = TableFileName(
+      ioptions_.cf_paths, file_meta.fd.GetNumber(), file_meta.fd.GetPathId());
+  std::unique_ptr<FSRandomAccessFile> file;
+  FileOptions fopts = file_options;
+  fopts.temperature = file_temperature;
+  Status s = PrepareIOFromReadOptions(ro, ioptions_.clock, fopts.io_options);
+  TEST_SYNC_POINT_CALLBACK("TableCache::GetTableReader:BeforeOpenFile",
+                           const_cast<Status*>(&s));
+  if (s.ok()) {
+    s = ioptions_.fs->NewRandomAccessFile(fname, fopts, &file, nullptr);
+  }
+  if (s.ok()) {
+    RecordTick(ioptions_.stats, NO_FILE_OPENS);
+  } else if (s.IsPathNotFound()) {
+    fname = Rocks2LevelTableFileName(fname);
+    s = PrepareIOFromReadOptions(ro, ioptions_.clock, fopts.io_options);
+    if (s.ok()) {
+      s = ioptions_.fs->NewRandomAccessFile(fname, file_options, &file,
+                                            nullptr);
+    }
+    if (s.ok()) {
+      RecordTick(ioptions_.stats, NO_FILE_OPENS);
+    }
+  }
+
+  if (s.ok()) {
+    if (!sequential_mode && ioptions_.advise_random_on_open) {
+      file->Hint(FSRandomAccessFile::kRandom);
+    }
+    StopWatch sw(ioptions_.clock, ioptions_.stats, TABLE_OPEN_IO_MICROS);
+    std::unique_ptr<RandomAccessFileReader> file_reader(
+        new RandomAccessFileReader(
+            std::move(file), fname, ioptions_.clock, io_tracer_,
+            record_read_stats ? ioptions_.stats : nullptr, SST_READ_MICROS,
+            file_read_hist, ioptions_.rate_limiter.get(), ioptions_.listeners,
+            file_temperature, level == ioptions_.num_levels - 1));
+    UniqueId64x2 expected_unique_id;
+    if (ioptions_.verify_sst_unique_id_in_manifest) {
+      expected_unique_id = file_meta.unique_id;
+    } else {
+      expected_unique_id = kNullUniqueId64x2;  // null ID == no verification
+    }
+    s = ioptions_.table_factory->NewTableReader(
+        ro,
+        TableReaderOptions(ioptions_, prefix_extractor, file_options,
+                           internal_comparator, skip_filters, immortal_tables_,
+                           false /* force_direct_prefetch */, level,
+                           block_cache_tracer_, max_file_size_for_l0_meta_pin,
+                           db_session_id_, file_meta.fd.GetNumber(),
+                           expected_unique_id, file_meta.fd.largest_seqno),
+        std::move(file_reader), file_meta.fd.GetFileSize(), table_reader,
+        prefetch_index_and_filter_in_cache);
+    TEST_SYNC_POINT("TableCache::GetTableReader:0");
+  }
+  return s;
+}
+
+void TableCache::EraseHandle(const FileDescriptor& fd, Cache::Handle* handle) {
+  ReleaseHandle(handle);
+  uint64_t number = fd.GetNumber();
+  Slice key = GetSliceForFileNumber(&number);
+  cache_->Erase(key);
+}
+
+Status TableCache::FindTable(
+    const ReadOptions& ro, const FileOptions& file_options,
+    const InternalKeyComparator& internal_comparator,
+    const FileMetaData& file_meta, Cache::Handle** handle,
+    const std::shared_ptr<const SliceTransform>& prefix_extractor,
+    const bool no_io, bool record_read_stats, HistogramImpl* file_read_hist,
+    bool skip_filters, int level, bool prefetch_index_and_filter_in_cache,
+    size_t max_file_size_for_l0_meta_pin, Temperature file_temperature) {
+  PERF_TIMER_GUARD_WITH_CLOCK(find_table_nanos, ioptions_.clock);
+  uint64_t number = file_meta.fd.GetNumber();
+  Slice key = GetSliceForFileNumber(&number);
+  *handle = cache_->Lookup(key);
+  TEST_SYNC_POINT_CALLBACK("TableCache::FindTable:0",
+                           const_cast<bool*>(&no_io));
+
+  if (*handle == nullptr) {
+    if (no_io) {
+      return Status::Incomplete("Table not found in table_cache, no_io is set");
+    }
+    MutexLock load_lock(loader_mutex_.get(key));
+    // We check the cache again under loading mutex
+    *handle = cache_->Lookup(key);
+    if (*handle != nullptr) {
+      return Status::OK();
+    }
+
+    std::unique_ptr<TableReader> table_reader;
+    Status s =
+        GetTableReader(ro, file_options, internal_comparator, file_meta,
+                       false /* sequential mode */, record_read_stats,
+                       file_read_hist, &table_reader, prefix_extractor,
+                       skip_filters, level, prefetch_index_and_filter_in_cache,
+                       max_file_size_for_l0_meta_pin, file_temperature);
+    if (!s.ok()) {
+      assert(table_reader == nullptr);
+      RecordTick(ioptions_.stats, NO_FILE_ERRORS);
+      // We do not cache error results so that if the error is transient,
+      // or somebody repairs the file, we recover automatically.
+    } else {
+      s = cache_->Insert(key, table_reader.get(), 1, &DeleteEntry<TableReader>,
+                         handle);
+      if (s.ok()) {
+        // Release ownership of table reader.
+        table_reader.release();
+      }
+    }
+    return s;
+  }
+  return Status::OK();
+}
+
+InternalIterator* TableCache::NewIterator(
+    const ReadOptions& options, const FileOptions& file_options,
+    const InternalKeyComparator& icomparator, const FileMetaData& file_meta,
+    RangeDelAggregator* range_del_agg,
+    const std::shared_ptr<const SliceTransform>& prefix_extractor,
+    TableReader** table_reader_ptr, HistogramImpl* file_read_hist,
+    TableReaderCaller caller, Arena* arena, bool skip_filters, int level,
+    size_t max_file_size_for_l0_meta_pin,
+    const InternalKey* smallest_compaction_key,
+    const InternalKey* largest_compaction_key, bool allow_unprepared_value,
+    TruncatedRangeDelIterator** range_del_iter) {
+  PERF_TIMER_GUARD(new_table_iterator_nanos);
+
+  Status s;
+  TableReader* table_reader = nullptr;
+  Cache::Handle* handle = nullptr;
+  if (table_reader_ptr != nullptr) {
+    *table_reader_ptr = nullptr;
+  }
+  bool for_compaction = caller == TableReaderCaller::kCompaction;
+  auto& fd = file_meta.fd;
+  table_reader = fd.table_reader;
+  if (table_reader == nullptr) {
+    s = FindTable(
+        options, file_options, icomparator, file_meta, &handle,
+        prefix_extractor, options.read_tier == kBlockCacheTier /* no_io */,
+        !for_compaction /* record_read_stats */, file_read_hist, skip_filters,
+        level, true /* prefetch_index_and_filter_in_cache */,
+        max_file_size_for_l0_meta_pin, file_meta.temperature);
+    if (s.ok()) {
+      table_reader = GetTableReaderFromHandle(handle);
+    }
+  }
+  InternalIterator* result = nullptr;
+  if (s.ok()) {
+    if (options.table_filter &&
+        !options.table_filter(*table_reader->GetTableProperties())) {
+      result = NewEmptyInternalIterator<Slice>(arena);
+    } else {
+      result = table_reader->NewIterator(
+          options, prefix_extractor.get(), arena, skip_filters, caller,
+          file_options.compaction_readahead_size, allow_unprepared_value);
+    }
+    if (handle != nullptr) {
+      result->RegisterCleanup(&UnrefEntry, cache_, handle);
+      handle = nullptr;  // prevent from releasing below
+    }
+
+    if (for_compaction) {
+      table_reader->SetupForCompaction();
+    }
+    if (table_reader_ptr != nullptr) {
+      *table_reader_ptr = table_reader;
+    }
+  }
+  if (s.ok() && !options.ignore_range_deletions) {
+    if (range_del_iter != nullptr) {
+      auto new_range_del_iter =
+          table_reader->NewRangeTombstoneIterator(options);
+      if (new_range_del_iter == nullptr || new_range_del_iter->empty()) {
+        delete new_range_del_iter;
+        *range_del_iter = nullptr;
+      } else {
+        *range_del_iter = new TruncatedRangeDelIterator(
+            std::unique_ptr<FragmentedRangeTombstoneIterator>(
+                new_range_del_iter),
+            &icomparator, &file_meta.smallest, &file_meta.largest);
+      }
+    }
+    if (range_del_agg != nullptr) {
+      if (range_del_agg->AddFile(fd.GetNumber())) {
+        std::unique_ptr<FragmentedRangeTombstoneIterator> new_range_del_iter(
+            static_cast<FragmentedRangeTombstoneIterator*>(
+                table_reader->NewRangeTombstoneIterator(options)));
+        if (new_range_del_iter != nullptr) {
+          s = new_range_del_iter->status();
+        }
+        if (s.ok()) {
+          const InternalKey* smallest = &file_meta.smallest;
+          const InternalKey* largest = &file_meta.largest;
+          if (smallest_compaction_key != nullptr) {
+            smallest = smallest_compaction_key;
+          }
+          if (largest_compaction_key != nullptr) {
+            largest = largest_compaction_key;
+          }
+          range_del_agg->AddTombstones(std::move(new_range_del_iter), smallest,
+                                       largest);
+        }
+      }
+    }
+  }
+
+  if (handle != nullptr) {
+    ReleaseHandle(handle);
+  }
+  if (!s.ok()) {
+    assert(result == nullptr);
+    result = NewErrorInternalIterator<Slice>(s, arena);
+  }
+  return result;
+}
+
+Status TableCache::GetRangeTombstoneIterator(
+    const ReadOptions& options,
+    const InternalKeyComparator& internal_comparator,
+    const FileMetaData& file_meta,
+    std::unique_ptr<FragmentedRangeTombstoneIterator>* out_iter) {
+  assert(out_iter);
+  const FileDescriptor& fd = file_meta.fd;
+  Status s;
+  TableReader* t = fd.table_reader;
+  Cache::Handle* handle = nullptr;
+  if (t == nullptr) {
+    s = FindTable(options, file_options_, internal_comparator, file_meta,
+                  &handle);
+    if (s.ok()) {
+      t = GetTableReaderFromHandle(handle);
+    }
+  }
+  if (s.ok()) {
+    // Note: NewRangeTombstoneIterator could return nullptr
+    out_iter->reset(t->NewRangeTombstoneIterator(options));
+  }
+  if (handle) {
+    if (*out_iter) {
+      (*out_iter)->RegisterCleanup(&UnrefEntry, cache_, handle);
+    } else {
+      ReleaseHandle(handle);
+    }
+  }
+  return s;
+}
+
+#ifndef ROCKSDB_LITE
+void TableCache::CreateRowCacheKeyPrefix(const ReadOptions& options,
+                                         const FileDescriptor& fd,
+                                         const Slice& internal_key,
+                                         GetContext* get_context,
+                                         IterKey& row_cache_key) {
+  uint64_t fd_number = fd.GetNumber();
+  // We use the user key as cache key instead of the internal key,
+  // otherwise the whole cache would be invalidated every time the
+  // sequence key increases. However, to support caching snapshot
+  // reads, we append the sequence number (incremented by 1 to
+  // distinguish from 0) only in this case.
+  // If the snapshot is larger than the largest seqno in the file,
+  // all data should be exposed to the snapshot, so we treat it
+  // the same as there is no snapshot. The exception is that if
+  // a seq-checking callback is registered, some internal keys
+  // may still be filtered out.
+  uint64_t seq_no = 0;
+  // Maybe we can include the whole file ifsnapshot == fd.largest_seqno.
+  if (options.snapshot != nullptr &&
+      (get_context->has_callback() ||
+       static_cast_with_check<const SnapshotImpl>(options.snapshot)
+               ->GetSequenceNumber() <= fd.largest_seqno)) {
+    // We should consider to use options.snapshot->GetSequenceNumber()
+    // instead of GetInternalKeySeqno(k), which will make the code
+    // easier to understand.
+    seq_no = 1 + GetInternalKeySeqno(internal_key);
+  }
+
+  // Compute row cache key.
+  row_cache_key.TrimAppend(row_cache_key.Size(), row_cache_id_.data(),
+                           row_cache_id_.size());
+  AppendVarint64(&row_cache_key, fd_number);
+  AppendVarint64(&row_cache_key, seq_no);
+}
+
+bool TableCache::GetFromRowCache(const Slice& user_key, IterKey& row_cache_key,
+                                 size_t prefix_size, GetContext* get_context) {
+  bool found = false;
+
+  row_cache_key.TrimAppend(prefix_size, user_key.data(), user_key.size());
+  if (auto row_handle =
+          ioptions_.row_cache->Lookup(row_cache_key.GetUserKey())) {
+    // Cleanable routine to release the cache entry
+    Cleanable value_pinner;
+    auto release_cache_entry_func = [](void* cache_to_clean,
+                                       void* cache_handle) {
+      ((Cache*)cache_to_clean)->Release((Cache::Handle*)cache_handle);
+    };
+    auto found_row_cache_entry =
+        static_cast<const std::string*>(ioptions_.row_cache->Value(row_handle));
+    // If it comes here value is located on the cache.
+    // found_row_cache_entry points to the value on cache,
+    // and value_pinner has cleanup procedure for the cached entry.
+    // After replayGetContextLog() returns, get_context.pinnable_slice_
+    // will point to cache entry buffer (or a copy based on that) and
+    // cleanup routine under value_pinner will be delegated to
+    // get_context.pinnable_slice_. Cache entry is released when
+    // get_context.pinnable_slice_ is reset.
+    value_pinner.RegisterCleanup(release_cache_entry_func,
+                                 ioptions_.row_cache.get(), row_handle);
+    replayGetContextLog(*found_row_cache_entry, user_key, get_context,
+                        &value_pinner);
+    RecordTick(ioptions_.stats, ROW_CACHE_HIT);
+    found = true;
+  } else {
+    RecordTick(ioptions_.stats, ROW_CACHE_MISS);
+  }
+  return found;
+}
+#endif  // ROCKSDB_LITE
+
+Status TableCache::Get(
+    const ReadOptions& options,
+    const InternalKeyComparator& internal_comparator,
+    const FileMetaData& file_meta, const Slice& k, GetContext* get_context,
+    const std::shared_ptr<const SliceTransform>& prefix_extractor,
+    HistogramImpl* file_read_hist, bool skip_filters, int level,
+    size_t max_file_size_for_l0_meta_pin) {
+  auto& fd = file_meta.fd;
+  std::string* row_cache_entry = nullptr;
+  bool done = false;
+#ifndef ROCKSDB_LITE
+  IterKey row_cache_key;
+  std::string row_cache_entry_buffer;
+
+  // Check row cache if enabled. Since row cache does not currently store
+  // sequence numbers, we cannot use it if we need to fetch the sequence.
+  if (ioptions_.row_cache && !get_context->NeedToReadSequence()) {
+    auto user_key = ExtractUserKey(k);
+    CreateRowCacheKeyPrefix(options, fd, k, get_context, row_cache_key);
+    done = GetFromRowCache(user_key, row_cache_key, row_cache_key.Size(),
+                           get_context);
+    if (!done) {
+      row_cache_entry = &row_cache_entry_buffer;
+    }
+  }
+#endif  // ROCKSDB_LITE
+  Status s;
+  TableReader* t = fd.table_reader;
+  Cache::Handle* handle = nullptr;
+  if (!done) {
+    assert(s.ok());
+    if (t == nullptr) {
+      s = FindTable(options, file_options_, internal_comparator, file_meta,
+                    &handle, prefix_extractor,
+                    options.read_tier == kBlockCacheTier /* no_io */,
+                    true /* record_read_stats */, file_read_hist, skip_filters,
+                    level, true /* prefetch_index_and_filter_in_cache */,
+                    max_file_size_for_l0_meta_pin, file_meta.temperature);
+      if (s.ok()) {
+        t = GetTableReaderFromHandle(handle);
+      }
+    }
+    SequenceNumber* max_covering_tombstone_seq =
+        get_context->max_covering_tombstone_seq();
+    if (s.ok() && max_covering_tombstone_seq != nullptr &&
+        !options.ignore_range_deletions) {
+      std::unique_ptr<FragmentedRangeTombstoneIterator> range_del_iter(
+          t->NewRangeTombstoneIterator(options));
+      if (range_del_iter != nullptr) {
+        SequenceNumber seq =
+            range_del_iter->MaxCoveringTombstoneSeqnum(ExtractUserKey(k));
+        if (seq > *max_covering_tombstone_seq) {
+          *max_covering_tombstone_seq = seq;
+          if (get_context->NeedTimestamp()) {
+            get_context->SetTimestampFromRangeTombstone(
+                range_del_iter->timestamp());
+          }
+        }
+      }
+    }
+    if (s.ok()) {
+      get_context->SetReplayLog(row_cache_entry);  // nullptr if no cache.
+      s = t->Get(options, k, get_context, prefix_extractor.get(), skip_filters);
+      get_context->SetReplayLog(nullptr);
+    } else if (options.read_tier == kBlockCacheTier && s.IsIncomplete()) {
+      // Couldn't find Table in cache but treat as kFound if no_io set
+      get_context->MarkKeyMayExist();
+      s = Status::OK();
+      done = true;
+    }
+  }
+
+#ifndef ROCKSDB_LITE
+  // Put the replay log in row cache only if something was found.
+  if (!done && s.ok() && row_cache_entry && !row_cache_entry->empty()) {
+    size_t charge = row_cache_entry->capacity() + sizeof(std::string);
+    void* row_ptr = new std::string(std::move(*row_cache_entry));
+    // If row cache is full, it's OK to continue.
+    ioptions_.row_cache
+        ->Insert(row_cache_key.GetUserKey(), row_ptr, charge,
+                 &DeleteEntry<std::string>)
+        .PermitUncheckedError();
+  }
+#endif  // ROCKSDB_LITE
+
+  if (handle != nullptr) {
+    ReleaseHandle(handle);
+  }
+  return s;
+}
+
+void TableCache::UpdateRangeTombstoneSeqnums(
+    const ReadOptions& options, TableReader* t,
+    MultiGetContext::Range& table_range) {
+  std::unique_ptr<FragmentedRangeTombstoneIterator> range_del_iter(
+      t->NewRangeTombstoneIterator(options));
+  if (range_del_iter != nullptr) {
+    for (auto iter = table_range.begin(); iter != table_range.end(); ++iter) {
+      SequenceNumber* max_covering_tombstone_seq =
+          iter->get_context->max_covering_tombstone_seq();
+      SequenceNumber seq =
+          range_del_iter->MaxCoveringTombstoneSeqnum(iter->ukey_with_ts);
+      if (seq > *max_covering_tombstone_seq) {
+        *max_covering_tombstone_seq = seq;
+        if (iter->get_context->NeedTimestamp()) {
+          iter->get_context->SetTimestampFromRangeTombstone(
+              range_del_iter->timestamp());
+        }
+      }
+    }
+  }
+}
+
+Status TableCache::MultiGetFilter(
+    const ReadOptions& options,
+    const InternalKeyComparator& internal_comparator,
+    const FileMetaData& file_meta,
+    const std::shared_ptr<const SliceTransform>& prefix_extractor,
+    HistogramImpl* file_read_hist, int level,
+    MultiGetContext::Range* mget_range, Cache::Handle** table_handle) {
+  auto& fd = file_meta.fd;
+#ifndef ROCKSDB_LITE
+  IterKey row_cache_key;
+  std::string row_cache_entry_buffer;
+
+  // Check if we need to use the row cache. If yes, then we cannot do the
+  // filtering here, since the filtering needs to happen after the row cache
+  // lookup.
+  KeyContext& first_key = *mget_range->begin();
+  if (ioptions_.row_cache && !first_key.get_context->NeedToReadSequence()) {
+    return Status::NotSupported();
+  }
+#endif  // ROCKSDB_LITE
+  Status s;
+  TableReader* t = fd.table_reader;
+  Cache::Handle* handle = nullptr;
+  MultiGetContext::Range tombstone_range(*mget_range, mget_range->begin(),
+                                         mget_range->end());
+  if (t == nullptr) {
+    s = FindTable(
+        options, file_options_, internal_comparator, file_meta, &handle,
+        prefix_extractor, options.read_tier == kBlockCacheTier /* no_io */,
+        true /* record_read_stats */, file_read_hist, /*skip_filters=*/false,
+        level, true /* prefetch_index_and_filter_in_cache */,
+        /*max_file_size_for_l0_meta_pin=*/0, file_meta.temperature);
+    if (s.ok()) {
+      t = GetTableReaderFromHandle(handle);
+    }
+    *table_handle = handle;
+  }
+  if (s.ok()) {
+    s = t->MultiGetFilter(options, prefix_extractor.get(), mget_range);
+  }
+  if (s.ok() && !options.ignore_range_deletions) {
+    // Update the range tombstone sequence numbers for the keys here
+    // as TableCache::MultiGet may or may not be called, and even if it
+    // is, it may be called with fewer keys in the rangedue to filtering.
+    UpdateRangeTombstoneSeqnums(options, t, tombstone_range);
+  }
+  if (mget_range->empty() && handle) {
+    ReleaseHandle(handle);
+    *table_handle = nullptr;
+  }
+
+  return s;
+}
+
+Status TableCache::GetTableProperties(
+    const FileOptions& file_options,
+    const InternalKeyComparator& internal_comparator,
+    const FileMetaData& file_meta,
+    std::shared_ptr<const TableProperties>* properties,
+    const std::shared_ptr<const SliceTransform>& prefix_extractor, bool no_io) {
+  auto table_reader = file_meta.fd.table_reader;
+  // table already been pre-loaded?
+  if (table_reader) {
+    *properties = table_reader->GetTableProperties();
+
+    return Status::OK();
+  }
+
+  Cache::Handle* table_handle = nullptr;
+  Status s = FindTable(ReadOptions(), file_options, internal_comparator,
+                       file_meta, &table_handle, prefix_extractor, no_io);
+  if (!s.ok()) {
+    return s;
+  }
+  assert(table_handle);
+  auto table = GetTableReaderFromHandle(table_handle);
+  *properties = table->GetTableProperties();
+  ReleaseHandle(table_handle);
+  return s;
+}
+
+Status TableCache::ApproximateKeyAnchors(
+    const ReadOptions& ro, const InternalKeyComparator& internal_comparator,
+    const FileMetaData& file_meta, std::vector<TableReader::Anchor>& anchors) {
+  Status s;
+  TableReader* t = file_meta.fd.table_reader;
+  Cache::Handle* handle = nullptr;
+  if (t == nullptr) {
+    s = FindTable(ro, file_options_, internal_comparator, file_meta, &handle);
+    if (s.ok()) {
+      t = GetTableReaderFromHandle(handle);
+    }
+  }
+  if (s.ok() && t != nullptr) {
+    s = t->ApproximateKeyAnchors(ro, anchors);
+  }
+  if (handle != nullptr) {
+    ReleaseHandle(handle);
+  }
+  return s;
+}
+
+size_t TableCache::GetMemoryUsageByTableReader(
+    const FileOptions& file_options,
+    const InternalKeyComparator& internal_comparator,
+    const FileMetaData& file_meta,
+    const std::shared_ptr<const SliceTransform>& prefix_extractor) {
+  auto table_reader = file_meta.fd.table_reader;
+  // table already been pre-loaded?
+  if (table_reader) {
+    return table_reader->ApproximateMemoryUsage();
+  }
+
+  Cache::Handle* table_handle = nullptr;
+  Status s = FindTable(ReadOptions(), file_options, internal_comparator,
+                       file_meta, &table_handle, prefix_extractor, true);
+  if (!s.ok()) {
+    return 0;
+  }
+  assert(table_handle);
+  auto table = GetTableReaderFromHandle(table_handle);
+  auto ret = table->ApproximateMemoryUsage();
+  ReleaseHandle(table_handle);
+  return ret;
+}
+
+bool TableCache::HasEntry(Cache* cache, uint64_t file_number) {
+  Cache::Handle* handle = cache->Lookup(GetSliceForFileNumber(&file_number));
+  if (handle) {
+    cache->Release(handle);
+    return true;
+  } else {
+    return false;
+  }
+}
+
+void TableCache::Evict(Cache* cache, uint64_t file_number) {
+  cache->Erase(GetSliceForFileNumber(&file_number));
+}
+
+uint64_t TableCache::ApproximateOffsetOf(
+    const Slice& key, const FileMetaData& file_meta, TableReaderCaller caller,
+    const InternalKeyComparator& internal_comparator,
+    const std::shared_ptr<const SliceTransform>& prefix_extractor) {
+  uint64_t result = 0;
+  TableReader* table_reader = file_meta.fd.table_reader;
+  Cache::Handle* table_handle = nullptr;
+  if (table_reader == nullptr) {
+    const bool for_compaction = (caller == TableReaderCaller::kCompaction);
+    Status s =
+        FindTable(ReadOptions(), file_options_, internal_comparator, file_meta,
+                  &table_handle, prefix_extractor, false /* no_io */,
+                  !for_compaction /* record_read_stats */);
+    if (s.ok()) {
+      table_reader = GetTableReaderFromHandle(table_handle);
+    }
+  }
+
+  if (table_reader != nullptr) {
+    result = table_reader->ApproximateOffsetOf(key, caller);
+  }
+  if (table_handle != nullptr) {
+    ReleaseHandle(table_handle);
+  }
+
+  return result;
+}
+
+uint64_t TableCache::ApproximateSize(
+    const Slice& start, const Slice& end, const FileMetaData& file_meta,
+    TableReaderCaller caller, const InternalKeyComparator& internal_comparator,
+    const std::shared_ptr<const SliceTransform>& prefix_extractor) {
+  uint64_t result = 0;
+  TableReader* table_reader = file_meta.fd.table_reader;
+  Cache::Handle* table_handle = nullptr;
+  if (table_reader == nullptr) {
+    const bool for_compaction = (caller == TableReaderCaller::kCompaction);
+    Status s =
+        FindTable(ReadOptions(), file_options_, internal_comparator, file_meta,
+                  &table_handle, prefix_extractor, false /* no_io */,
+                  !for_compaction /* record_read_stats */);
+    if (s.ok()) {
+      table_reader = GetTableReaderFromHandle(table_handle);
+    }
+  }
+
+  if (table_reader != nullptr) {
+    result = table_reader->ApproximateSize(start, end, caller);
+  }
+  if (table_handle != nullptr) {
+    ReleaseHandle(table_handle);
+  }
+
+  return result;
+}
+}  // namespace ROCKSDB_NAMESPACE