Adding upstream version 18.2.2.upstream/18.2.2

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

1 files changed, 855 insertions, 0 deletions

diff --git a/src/rocksdb/db/compaction/compaction.cc b/src/rocksdb/db/compaction/compaction.cc
new file mode 100644
index 000000000..a32b529f7
--- /dev/null
+++ b/src/rocksdb/db/compaction/compaction.cc
@@ -0,0 +1,855 @@
+//  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/compaction/compaction.h"
+
+#include <cinttypes>
+#include <vector>
+
+#include "db/column_family.h"
+#include "rocksdb/compaction_filter.h"
+#include "rocksdb/sst_partitioner.h"
+#include "test_util/sync_point.h"
+#include "util/string_util.h"
+
+namespace ROCKSDB_NAMESPACE {
+
+const uint64_t kRangeTombstoneSentinel =
+    PackSequenceAndType(kMaxSequenceNumber, kTypeRangeDeletion);
+
+int sstableKeyCompare(const Comparator* user_cmp, const InternalKey& a,
+                      const InternalKey& b) {
+  auto c = user_cmp->CompareWithoutTimestamp(a.user_key(), b.user_key());
+  if (c != 0) {
+    return c;
+  }
+  auto a_footer = ExtractInternalKeyFooter(a.Encode());
+  auto b_footer = ExtractInternalKeyFooter(b.Encode());
+  if (a_footer == kRangeTombstoneSentinel) {
+    if (b_footer != kRangeTombstoneSentinel) {
+      return -1;
+    }
+  } else if (b_footer == kRangeTombstoneSentinel) {
+    return 1;
+  }
+  return 0;
+}
+
+int sstableKeyCompare(const Comparator* user_cmp, const InternalKey* a,
+                      const InternalKey& b) {
+  if (a == nullptr) {
+    return -1;
+  }
+  return sstableKeyCompare(user_cmp, *a, b);
+}
+
+int sstableKeyCompare(const Comparator* user_cmp, const InternalKey& a,
+                      const InternalKey* b) {
+  if (b == nullptr) {
+    return -1;
+  }
+  return sstableKeyCompare(user_cmp, a, *b);
+}
+
+uint64_t TotalFileSize(const std::vector<FileMetaData*>& files) {
+  uint64_t sum = 0;
+  for (size_t i = 0; i < files.size() && files[i]; i++) {
+    sum += files[i]->fd.GetFileSize();
+  }
+  return sum;
+}
+
+void Compaction::SetInputVersion(Version* _input_version) {
+  input_version_ = _input_version;
+  cfd_ = input_version_->cfd();
+
+  cfd_->Ref();
+  input_version_->Ref();
+  edit_.SetColumnFamily(cfd_->GetID());
+}
+
+void Compaction::GetBoundaryKeys(
+    VersionStorageInfo* vstorage,
+    const std::vector<CompactionInputFiles>& inputs, Slice* smallest_user_key,
+    Slice* largest_user_key, int exclude_level) {
+  bool initialized = false;
+  const Comparator* ucmp = vstorage->InternalComparator()->user_comparator();
+  for (size_t i = 0; i < inputs.size(); ++i) {
+    if (inputs[i].files.empty() || inputs[i].level == exclude_level) {
+      continue;
+    }
+    if (inputs[i].level == 0) {
+      // we need to consider all files on level 0
+      for (const auto* f : inputs[i].files) {
+        const Slice& start_user_key = f->smallest.user_key();
+        if (!initialized ||
+            ucmp->Compare(start_user_key, *smallest_user_key) < 0) {
+          *smallest_user_key = start_user_key;
+        }
+        const Slice& end_user_key = f->largest.user_key();
+        if (!initialized ||
+            ucmp->Compare(end_user_key, *largest_user_key) > 0) {
+          *largest_user_key = end_user_key;
+        }
+        initialized = true;
+      }
+    } else {
+      // we only need to consider the first and last file
+      const Slice& start_user_key = inputs[i].files[0]->smallest.user_key();
+      if (!initialized ||
+          ucmp->Compare(start_user_key, *smallest_user_key) < 0) {
+        *smallest_user_key = start_user_key;
+      }
+      const Slice& end_user_key = inputs[i].files.back()->largest.user_key();
+      if (!initialized || ucmp->Compare(end_user_key, *largest_user_key) > 0) {
+        *largest_user_key = end_user_key;
+      }
+      initialized = true;
+    }
+  }
+}
+
+std::vector<CompactionInputFiles> Compaction::PopulateWithAtomicBoundaries(
+    VersionStorageInfo* vstorage, std::vector<CompactionInputFiles> inputs) {
+  const Comparator* ucmp = vstorage->InternalComparator()->user_comparator();
+  for (size_t i = 0; i < inputs.size(); i++) {
+    if (inputs[i].level == 0 || inputs[i].files.empty()) {
+      continue;
+    }
+    inputs[i].atomic_compaction_unit_boundaries.reserve(inputs[i].files.size());
+    AtomicCompactionUnitBoundary cur_boundary;
+    size_t first_atomic_idx = 0;
+    auto add_unit_boundary = [&](size_t to) {
+      if (first_atomic_idx == to) return;
+      for (size_t k = first_atomic_idx; k < to; k++) {
+        inputs[i].atomic_compaction_unit_boundaries.push_back(cur_boundary);
+      }
+      first_atomic_idx = to;
+    };
+    for (size_t j = 0; j < inputs[i].files.size(); j++) {
+      const auto* f = inputs[i].files[j];
+      if (j == 0) {
+        // First file in a level.
+        cur_boundary.smallest = &f->smallest;
+        cur_boundary.largest = &f->largest;
+      } else if (sstableKeyCompare(ucmp, *cur_boundary.largest, f->smallest) ==
+                 0) {
+        // SSTs overlap but the end key of the previous file was not
+        // artificially extended by a range tombstone. Extend the current
+        // boundary.
+        cur_boundary.largest = &f->largest;
+      } else {
+        // Atomic compaction unit has ended.
+        add_unit_boundary(j);
+        cur_boundary.smallest = &f->smallest;
+        cur_boundary.largest = &f->largest;
+      }
+    }
+    add_unit_boundary(inputs[i].files.size());
+    assert(inputs[i].files.size() ==
+           inputs[i].atomic_compaction_unit_boundaries.size());
+  }
+  return inputs;
+}
+
+// helper function to determine if compaction is creating files at the
+// bottommost level
+bool Compaction::IsBottommostLevel(
+    int output_level, VersionStorageInfo* vstorage,
+    const std::vector<CompactionInputFiles>& inputs) {
+  int output_l0_idx;
+  if (output_level == 0) {
+    output_l0_idx = 0;
+    for (const auto* file : vstorage->LevelFiles(0)) {
+      if (inputs[0].files.back() == file) {
+        break;
+      }
+      ++output_l0_idx;
+    }
+    assert(static_cast<size_t>(output_l0_idx) < vstorage->LevelFiles(0).size());
+  } else {
+    output_l0_idx = -1;
+  }
+  Slice smallest_key, largest_key;
+  GetBoundaryKeys(vstorage, inputs, &smallest_key, &largest_key);
+  return !vstorage->RangeMightExistAfterSortedRun(smallest_key, largest_key,
+                                                  output_level, output_l0_idx);
+}
+
+// test function to validate the functionality of IsBottommostLevel()
+// function -- determines if compaction with inputs and storage is bottommost
+bool Compaction::TEST_IsBottommostLevel(
+    int output_level, VersionStorageInfo* vstorage,
+    const std::vector<CompactionInputFiles>& inputs) {
+  return IsBottommostLevel(output_level, vstorage, inputs);
+}
+
+bool Compaction::IsFullCompaction(
+    VersionStorageInfo* vstorage,
+    const std::vector<CompactionInputFiles>& inputs) {
+  size_t num_files_in_compaction = 0;
+  size_t total_num_files = 0;
+  for (int l = 0; l < vstorage->num_levels(); l++) {
+    total_num_files += vstorage->NumLevelFiles(l);
+  }
+  for (size_t i = 0; i < inputs.size(); i++) {
+    num_files_in_compaction += inputs[i].size();
+  }
+  return num_files_in_compaction == total_num_files;
+}
+
+Compaction::Compaction(
+    VersionStorageInfo* vstorage, const ImmutableOptions& _immutable_options,
+    const MutableCFOptions& _mutable_cf_options,
+    const MutableDBOptions& _mutable_db_options,
+    std::vector<CompactionInputFiles> _inputs, int _output_level,
+    uint64_t _target_file_size, uint64_t _max_compaction_bytes,
+    uint32_t _output_path_id, CompressionType _compression,
+    CompressionOptions _compression_opts, Temperature _output_temperature,
+    uint32_t _max_subcompactions, std::vector<FileMetaData*> _grandparents,
+    bool _manual_compaction, const std::string& _trim_ts, double _score,
+    bool _deletion_compaction, bool l0_files_might_overlap,
+    CompactionReason _compaction_reason,
+    BlobGarbageCollectionPolicy _blob_garbage_collection_policy,
+    double _blob_garbage_collection_age_cutoff)
+    : input_vstorage_(vstorage),
+      start_level_(_inputs[0].level),
+      output_level_(_output_level),
+      target_output_file_size_(_target_file_size),
+      max_compaction_bytes_(_max_compaction_bytes),
+      max_subcompactions_(_max_subcompactions),
+      immutable_options_(_immutable_options),
+      mutable_cf_options_(_mutable_cf_options),
+      input_version_(nullptr),
+      number_levels_(vstorage->num_levels()),
+      cfd_(nullptr),
+      output_path_id_(_output_path_id),
+      output_compression_(_compression),
+      output_compression_opts_(_compression_opts),
+      output_temperature_(_output_temperature),
+      deletion_compaction_(_deletion_compaction),
+      l0_files_might_overlap_(l0_files_might_overlap),
+      inputs_(PopulateWithAtomicBoundaries(vstorage, std::move(_inputs))),
+      grandparents_(std::move(_grandparents)),
+      score_(_score),
+      bottommost_level_(IsBottommostLevel(output_level_, vstorage, inputs_)),
+      is_full_compaction_(IsFullCompaction(vstorage, inputs_)),
+      is_manual_compaction_(_manual_compaction),
+      trim_ts_(_trim_ts),
+      is_trivial_move_(false),
+
+      compaction_reason_(_compaction_reason),
+      notify_on_compaction_completion_(false),
+      enable_blob_garbage_collection_(
+          _blob_garbage_collection_policy == BlobGarbageCollectionPolicy::kForce
+              ? true
+              : (_blob_garbage_collection_policy ==
+                         BlobGarbageCollectionPolicy::kDisable
+                     ? false
+                     : mutable_cf_options()->enable_blob_garbage_collection)),
+      blob_garbage_collection_age_cutoff_(
+          _blob_garbage_collection_age_cutoff < 0 ||
+                  _blob_garbage_collection_age_cutoff > 1
+              ? mutable_cf_options()->blob_garbage_collection_age_cutoff
+              : _blob_garbage_collection_age_cutoff),
+      penultimate_level_(EvaluatePenultimateLevel(
+          vstorage, immutable_options_, start_level_, output_level_)) {
+  MarkFilesBeingCompacted(true);
+  if (is_manual_compaction_) {
+    compaction_reason_ = CompactionReason::kManualCompaction;
+  }
+  if (max_subcompactions_ == 0) {
+    max_subcompactions_ = _mutable_db_options.max_subcompactions;
+  }
+
+  // for the non-bottommost levels, it tries to build files match the target
+  // file size, but not guaranteed. It could be 2x the size of the target size.
+  max_output_file_size_ =
+      bottommost_level_ || grandparents_.empty() ||
+              !_immutable_options.level_compaction_dynamic_file_size
+          ? target_output_file_size_
+          : 2 * target_output_file_size_;
+
+#ifndef NDEBUG
+  for (size_t i = 1; i < inputs_.size(); ++i) {
+    assert(inputs_[i].level > inputs_[i - 1].level);
+  }
+#endif
+
+  // setup input_levels_
+  {
+    input_levels_.resize(num_input_levels());
+    for (size_t which = 0; which < num_input_levels(); which++) {
+      DoGenerateLevelFilesBrief(&input_levels_[which], inputs_[which].files,
+                                &arena_);
+    }
+  }
+
+  GetBoundaryKeys(vstorage, inputs_, &smallest_user_key_, &largest_user_key_);
+
+  // Every compaction regardless of any compaction reason may respect the
+  // existing compact cursor in the output level to split output files
+  output_split_key_ = nullptr;
+  if (immutable_options_.compaction_style == kCompactionStyleLevel &&
+      immutable_options_.compaction_pri == kRoundRobin) {
+    const InternalKey* cursor =
+        &input_vstorage_->GetCompactCursors()[output_level_];
+    if (cursor->size() != 0) {
+      const Slice& cursor_user_key = ExtractUserKey(cursor->Encode());
+      auto ucmp = vstorage->InternalComparator()->user_comparator();
+      // May split output files according to the cursor if it in the user-key
+      // range
+      if (ucmp->CompareWithoutTimestamp(cursor_user_key, smallest_user_key_) >
+              0 &&
+          ucmp->CompareWithoutTimestamp(cursor_user_key, largest_user_key_) <=
+              0) {
+        output_split_key_ = cursor;
+      }
+    }
+  }
+
+  PopulatePenultimateLevelOutputRange();
+}
+
+void Compaction::PopulatePenultimateLevelOutputRange() {
+  if (!SupportsPerKeyPlacement()) {
+    return;
+  }
+
+  // exclude the last level, the range of all input levels is the safe range
+  // of keys that can be moved up.
+  int exclude_level = number_levels_ - 1;
+  penultimate_output_range_type_ = PenultimateOutputRangeType::kNonLastRange;
+
+  // For universal compaction, the penultimate_output_range could be extended if
+  // all penultimate level files are included in the compaction (which includes
+  // the case that the penultimate level is empty).
+  if (immutable_options_.compaction_style == kCompactionStyleUniversal) {
+    exclude_level = kInvalidLevel;
+    std::set<uint64_t> penultimate_inputs;
+    for (const auto& input_lvl : inputs_) {
+      if (input_lvl.level == penultimate_level_) {
+        for (const auto& file : input_lvl.files) {
+          penultimate_inputs.emplace(file->fd.GetNumber());
+        }
+      }
+    }
+    auto penultimate_files = input_vstorage_->LevelFiles(penultimate_level_);
+    for (const auto& file : penultimate_files) {
+      if (penultimate_inputs.find(file->fd.GetNumber()) ==
+          penultimate_inputs.end()) {
+        exclude_level = number_levels_ - 1;
+        penultimate_output_range_type_ = PenultimateOutputRangeType::kFullRange;
+        break;
+      }
+    }
+  }
+
+  GetBoundaryKeys(input_vstorage_, inputs_,
+                  &penultimate_level_smallest_user_key_,
+                  &penultimate_level_largest_user_key_, exclude_level);
+
+  // If there's a case that the penultimate level output range is overlapping
+  // with the existing files, disable the penultimate level output by setting
+  // the range to empty. One example is the range delete could have overlap
+  // boundary with the next file. (which is actually a false overlap)
+  // TODO: Exclude such false overlap, so it won't disable the penultimate
+  //  output.
+  std::set<uint64_t> penultimate_inputs;
+  for (const auto& input_lvl : inputs_) {
+    if (input_lvl.level == penultimate_level_) {
+      for (const auto& file : input_lvl.files) {
+        penultimate_inputs.emplace(file->fd.GetNumber());
+      }
+    }
+  }
+
+  auto penultimate_files = input_vstorage_->LevelFiles(penultimate_level_);
+  for (const auto& file : penultimate_files) {
+    if (penultimate_inputs.find(file->fd.GetNumber()) ==
+            penultimate_inputs.end() &&
+        OverlapPenultimateLevelOutputRange(file->smallest.user_key(),
+                                           file->largest.user_key())) {
+      // basically disable the penultimate range output. which should be rare
+      // or a false overlap caused by range del
+      penultimate_level_smallest_user_key_ = "";
+      penultimate_level_largest_user_key_ = "";
+      penultimate_output_range_type_ = PenultimateOutputRangeType::kDisabled;
+    }
+  }
+}
+
+Compaction::~Compaction() {
+  if (input_version_ != nullptr) {
+    input_version_->Unref();
+  }
+  if (cfd_ != nullptr) {
+    cfd_->UnrefAndTryDelete();
+  }
+}
+
+bool Compaction::SupportsPerKeyPlacement() const {
+  return penultimate_level_ != kInvalidLevel;
+}
+
+int Compaction::GetPenultimateLevel() const { return penultimate_level_; }
+
+// smallest_key and largest_key include timestamps if user-defined timestamp is
+// enabled.
+bool Compaction::OverlapPenultimateLevelOutputRange(
+    const Slice& smallest_key, const Slice& largest_key) const {
+  if (!SupportsPerKeyPlacement()) {
+    return false;
+  }
+  const Comparator* ucmp =
+      input_vstorage_->InternalComparator()->user_comparator();
+
+  return ucmp->CompareWithoutTimestamp(
+             smallest_key, penultimate_level_largest_user_key_) <= 0 &&
+         ucmp->CompareWithoutTimestamp(
+             largest_key, penultimate_level_smallest_user_key_) >= 0;
+}
+
+// key includes timestamp if user-defined timestamp is enabled.
+bool Compaction::WithinPenultimateLevelOutputRange(const Slice& key) const {
+  if (!SupportsPerKeyPlacement()) {
+    return false;
+  }
+
+  if (penultimate_level_smallest_user_key_.empty() ||
+      penultimate_level_largest_user_key_.empty()) {
+    return false;
+  }
+
+  const Comparator* ucmp =
+      input_vstorage_->InternalComparator()->user_comparator();
+
+  return ucmp->CompareWithoutTimestamp(
+             key, penultimate_level_smallest_user_key_) >= 0 &&
+         ucmp->CompareWithoutTimestamp(
+             key, penultimate_level_largest_user_key_) <= 0;
+}
+
+bool Compaction::InputCompressionMatchesOutput() const {
+  int base_level = input_vstorage_->base_level();
+  bool matches =
+      (GetCompressionType(input_vstorage_, mutable_cf_options_, start_level_,
+                          base_level) == output_compression_);
+  if (matches) {
+    TEST_SYNC_POINT("Compaction::InputCompressionMatchesOutput:Matches");
+    return true;
+  }
+  TEST_SYNC_POINT("Compaction::InputCompressionMatchesOutput:DidntMatch");
+  return matches;
+}
+
+bool Compaction::IsTrivialMove() const {
+  // Avoid a move if there is lots of overlapping grandparent data.
+  // Otherwise, the move could create a parent file that will require
+  // a very expensive merge later on.
+  // If start_level_== output_level_, the purpose is to force compaction
+  // filter to be applied to that level, and thus cannot be a trivial move.
+
+  // Check if start level have files with overlapping ranges
+  if (start_level_ == 0 && input_vstorage_->level0_non_overlapping() == false &&
+      l0_files_might_overlap_) {
+    // We cannot move files from L0 to L1 if the L0 files in the LSM-tree are
+    // overlapping, unless we are sure that files picked in L0 don't overlap.
+    return false;
+  }
+
+  if (is_manual_compaction_ &&
+      (immutable_options_.compaction_filter != nullptr ||
+       immutable_options_.compaction_filter_factory != nullptr)) {
+    // This is a manual compaction and we have a compaction filter that should
+    // be executed, we cannot do a trivial move
+    return false;
+  }
+
+  if (start_level_ == output_level_) {
+    // It doesn't make sense if compaction picker picks files just to trivial
+    // move to the same level.
+    return false;
+  }
+
+  // Used in universal compaction, where trivial move can be done if the
+  // input files are non overlapping
+  if ((mutable_cf_options_.compaction_options_universal.allow_trivial_move) &&
+      (output_level_ != 0) &&
+      (cfd_->ioptions()->compaction_style == kCompactionStyleUniversal)) {
+    return is_trivial_move_;
+  }
+
+  if (!(start_level_ != output_level_ && num_input_levels() == 1 &&
+        input(0, 0)->fd.GetPathId() == output_path_id() &&
+        InputCompressionMatchesOutput())) {
+    return false;
+  }
+
+  // assert inputs_.size() == 1
+
+  std::unique_ptr<SstPartitioner> partitioner = CreateSstPartitioner();
+
+  for (const auto& file : inputs_.front().files) {
+    std::vector<FileMetaData*> file_grand_parents;
+    if (output_level_ + 1 >= number_levels_) {
+      continue;
+    }
+    input_vstorage_->GetOverlappingInputs(output_level_ + 1, &file->smallest,
+                                          &file->largest, &file_grand_parents);
+    const auto compaction_size =
+        file->fd.GetFileSize() + TotalFileSize(file_grand_parents);
+    if (compaction_size > max_compaction_bytes_) {
+      return false;
+    }
+
+    if (partitioner.get() != nullptr) {
+      if (!partitioner->CanDoTrivialMove(file->smallest.user_key(),
+                                         file->largest.user_key())) {
+        return false;
+      }
+    }
+  }
+
+  // PerKeyPlacement compaction should never be trivial move.
+  if (SupportsPerKeyPlacement()) {
+    return false;
+  }
+
+  return true;
+}
+
+void Compaction::AddInputDeletions(VersionEdit* out_edit) {
+  for (size_t which = 0; which < num_input_levels(); which++) {
+    for (size_t i = 0; i < inputs_[which].size(); i++) {
+      out_edit->DeleteFile(level(which), inputs_[which][i]->fd.GetNumber());
+    }
+  }
+}
+
+bool Compaction::KeyNotExistsBeyondOutputLevel(
+    const Slice& user_key, std::vector<size_t>* level_ptrs) const {
+  assert(input_version_ != nullptr);
+  assert(level_ptrs != nullptr);
+  assert(level_ptrs->size() == static_cast<size_t>(number_levels_));
+  if (bottommost_level_) {
+    return true;
+  } else if (output_level_ != 0 &&
+             cfd_->ioptions()->compaction_style == kCompactionStyleLevel) {
+    // Maybe use binary search to find right entry instead of linear search?
+    const Comparator* user_cmp = cfd_->user_comparator();
+    for (int lvl = output_level_ + 1; lvl < number_levels_; lvl++) {
+      const std::vector<FileMetaData*>& files =
+          input_vstorage_->LevelFiles(lvl);
+      for (; level_ptrs->at(lvl) < files.size(); level_ptrs->at(lvl)++) {
+        auto* f = files[level_ptrs->at(lvl)];
+        if (user_cmp->Compare(user_key, f->largest.user_key()) <= 0) {
+          // We've advanced far enough
+          // In the presence of user-defined timestamp, we may need to handle
+          // the case in which f->smallest.user_key() (including ts) has the
+          // same user key, but the ts part is smaller. If so,
+          // Compare(user_key, f->smallest.user_key()) returns -1.
+          // That's why we need CompareWithoutTimestamp().
+          if (user_cmp->CompareWithoutTimestamp(user_key,
+                                                f->smallest.user_key()) >= 0) {
+            // Key falls in this file's range, so it may
+            // exist beyond output level
+            return false;
+          }
+          break;
+        }
+      }
+    }
+    return true;
+  }
+  return false;
+}
+
+// Mark (or clear) each file that is being compacted
+void Compaction::MarkFilesBeingCompacted(bool mark_as_compacted) {
+  for (size_t i = 0; i < num_input_levels(); i++) {
+    for (size_t j = 0; j < inputs_[i].size(); j++) {
+      assert(mark_as_compacted ? !inputs_[i][j]->being_compacted
+                               : inputs_[i][j]->being_compacted);
+      inputs_[i][j]->being_compacted = mark_as_compacted;
+    }
+  }
+}
+
+// Sample output:
+// If compacting 3 L0 files, 2 L3 files and 1 L4 file, and outputting to L5,
+// print: "3@0 + 2@3 + 1@4 files to L5"
+const char* Compaction::InputLevelSummary(
+    InputLevelSummaryBuffer* scratch) const {
+  int len = 0;
+  bool is_first = true;
+  for (auto& input_level : inputs_) {
+    if (input_level.empty()) {
+      continue;
+    }
+    if (!is_first) {
+      len +=
+          snprintf(scratch->buffer + len, sizeof(scratch->buffer) - len, " + ");
+      len = std::min(len, static_cast<int>(sizeof(scratch->buffer)));
+    } else {
+      is_first = false;
+    }
+    len += snprintf(scratch->buffer + len, sizeof(scratch->buffer) - len,
+                    "%" ROCKSDB_PRIszt "@%d", input_level.size(),
+                    input_level.level);
+    len = std::min(len, static_cast<int>(sizeof(scratch->buffer)));
+  }
+  snprintf(scratch->buffer + len, sizeof(scratch->buffer) - len,
+           " files to L%d", output_level());
+
+  return scratch->buffer;
+}
+
+uint64_t Compaction::CalculateTotalInputSize() const {
+  uint64_t size = 0;
+  for (auto& input_level : inputs_) {
+    for (auto f : input_level.files) {
+      size += f->fd.GetFileSize();
+    }
+  }
+  return size;
+}
+
+void Compaction::ReleaseCompactionFiles(Status status) {
+  MarkFilesBeingCompacted(false);
+  cfd_->compaction_picker()->ReleaseCompactionFiles(this, status);
+}
+
+void Compaction::ResetNextCompactionIndex() {
+  assert(input_version_ != nullptr);
+  input_vstorage_->ResetNextCompactionIndex(start_level_);
+}
+
+namespace {
+int InputSummary(const std::vector<FileMetaData*>& files, char* output,
+                 int len) {
+  *output = '\0';
+  int write = 0;
+  for (size_t i = 0; i < files.size(); i++) {
+    int sz = len - write;
+    int ret;
+    char sztxt[16];
+    AppendHumanBytes(files.at(i)->fd.GetFileSize(), sztxt, 16);
+    ret = snprintf(output + write, sz, "%" PRIu64 "(%s) ",
+                   files.at(i)->fd.GetNumber(), sztxt);
+    if (ret < 0 || ret >= sz) break;
+    write += ret;
+  }
+  // if files.size() is non-zero, overwrite the last space
+  return write - !!files.size();
+}
+}  // namespace
+
+void Compaction::Summary(char* output, int len) {
+  int write =
+      snprintf(output, len, "Base version %" PRIu64 " Base level %d, inputs: [",
+               input_version_->GetVersionNumber(), start_level_);
+  if (write < 0 || write >= len) {
+    return;
+  }
+
+  for (size_t level_iter = 0; level_iter < num_input_levels(); ++level_iter) {
+    if (level_iter > 0) {
+      write += snprintf(output + write, len - write, "], [");
+      if (write < 0 || write >= len) {
+        return;
+      }
+    }
+    write +=
+        InputSummary(inputs_[level_iter].files, output + write, len - write);
+    if (write < 0 || write >= len) {
+      return;
+    }
+  }
+
+  snprintf(output + write, len - write, "]");
+}
+
+uint64_t Compaction::OutputFilePreallocationSize() const {
+  uint64_t preallocation_size = 0;
+
+  for (const auto& level_files : inputs_) {
+    for (const auto& file : level_files.files) {
+      preallocation_size += file->fd.GetFileSize();
+    }
+  }
+
+  if (max_output_file_size_ != std::numeric_limits<uint64_t>::max() &&
+      (immutable_options_.compaction_style == kCompactionStyleLevel ||
+       output_level() > 0)) {
+    preallocation_size = std::min(max_output_file_size_, preallocation_size);
+  }
+
+  // Over-estimate slightly so we don't end up just barely crossing
+  // the threshold
+  // No point to preallocate more than 1GB.
+  return std::min(uint64_t{1073741824},
+                  preallocation_size + (preallocation_size / 10));
+}
+
+std::unique_ptr<CompactionFilter> Compaction::CreateCompactionFilter() const {
+  if (!cfd_->ioptions()->compaction_filter_factory) {
+    return nullptr;
+  }
+
+  if (!cfd_->ioptions()
+           ->compaction_filter_factory->ShouldFilterTableFileCreation(
+               TableFileCreationReason::kCompaction)) {
+    return nullptr;
+  }
+
+  CompactionFilter::Context context;
+  context.is_full_compaction = is_full_compaction_;
+  context.is_manual_compaction = is_manual_compaction_;
+  context.column_family_id = cfd_->GetID();
+  context.reason = TableFileCreationReason::kCompaction;
+  return cfd_->ioptions()->compaction_filter_factory->CreateCompactionFilter(
+      context);
+}
+
+std::unique_ptr<SstPartitioner> Compaction::CreateSstPartitioner() const {
+  if (!immutable_options_.sst_partitioner_factory) {
+    return nullptr;
+  }
+
+  SstPartitioner::Context context;
+  context.is_full_compaction = is_full_compaction_;
+  context.is_manual_compaction = is_manual_compaction_;
+  context.output_level = output_level_;
+  context.smallest_user_key = smallest_user_key_;
+  context.largest_user_key = largest_user_key_;
+  return immutable_options_.sst_partitioner_factory->CreatePartitioner(context);
+}
+
+bool Compaction::IsOutputLevelEmpty() const {
+  return inputs_.back().level != output_level_ || inputs_.back().empty();
+}
+
+bool Compaction::ShouldFormSubcompactions() const {
+  if (cfd_ == nullptr) {
+    return false;
+  }
+
+  // Round-Robin pri under leveled compaction allows subcompactions by default
+  // and the number of subcompactions can be larger than max_subcompactions_
+  if (cfd_->ioptions()->compaction_pri == kRoundRobin &&
+      cfd_->ioptions()->compaction_style == kCompactionStyleLevel) {
+    return output_level_ > 0;
+  }
+
+  if (max_subcompactions_ <= 1) {
+    return false;
+  }
+
+  if (cfd_->ioptions()->compaction_style == kCompactionStyleLevel) {
+    return (start_level_ == 0 || is_manual_compaction_) && output_level_ > 0;
+  } else if (cfd_->ioptions()->compaction_style == kCompactionStyleUniversal) {
+    return number_levels_ > 1 && output_level_ > 0;
+  } else {
+    return false;
+  }
+}
+
+bool Compaction::DoesInputReferenceBlobFiles() const {
+  assert(input_version_);
+
+  const VersionStorageInfo* storage_info = input_version_->storage_info();
+  assert(storage_info);
+
+  if (storage_info->GetBlobFiles().empty()) {
+    return false;
+  }
+
+  for (size_t i = 0; i < inputs_.size(); ++i) {
+    for (const FileMetaData* meta : inputs_[i].files) {
+      assert(meta);
+
+      if (meta->oldest_blob_file_number != kInvalidBlobFileNumber) {
+        return true;
+      }
+    }
+  }
+
+  return false;
+}
+
+uint64_t Compaction::MinInputFileOldestAncesterTime(
+    const InternalKey* start, const InternalKey* end) const {
+  uint64_t min_oldest_ancester_time = std::numeric_limits<uint64_t>::max();
+  const InternalKeyComparator& icmp =
+      column_family_data()->internal_comparator();
+  for (const auto& level_files : inputs_) {
+    for (const auto& file : level_files.files) {
+      if (start != nullptr && icmp.Compare(file->largest, *start) < 0) {
+        continue;
+      }
+      if (end != nullptr && icmp.Compare(file->smallest, *end) > 0) {
+        continue;
+      }
+      uint64_t oldest_ancester_time = file->TryGetOldestAncesterTime();
+      if (oldest_ancester_time != 0) {
+        min_oldest_ancester_time =
+            std::min(min_oldest_ancester_time, oldest_ancester_time);
+      }
+    }
+  }
+  return min_oldest_ancester_time;
+}
+
+int Compaction::EvaluatePenultimateLevel(
+    const VersionStorageInfo* vstorage,
+    const ImmutableOptions& immutable_options, const int start_level,
+    const int output_level) {
+  // TODO: currently per_key_placement feature only support level and universal
+  //  compaction
+  if (immutable_options.compaction_style != kCompactionStyleLevel &&
+      immutable_options.compaction_style != kCompactionStyleUniversal) {
+    return kInvalidLevel;
+  }
+  if (output_level != immutable_options.num_levels - 1) {
+    return kInvalidLevel;
+  }
+
+  int penultimate_level = output_level - 1;
+  assert(penultimate_level < immutable_options.num_levels);
+  if (penultimate_level <= 0) {
+    return kInvalidLevel;
+  }
+
+  // If the penultimate level is not within input level -> output level range
+  // check if the penultimate output level is empty, if it's empty, it could
+  // also be locked for the penultimate output.
+  // TODO: ideally, it only needs to check if there's a file within the
+  //  compaction output key range. For simplicity, it just check if there's any
+  //  file on the penultimate level.
+  if (start_level == immutable_options.num_levels - 1 &&
+      (immutable_options.compaction_style != kCompactionStyleUniversal ||
+       !vstorage->LevelFiles(penultimate_level).empty())) {
+    return kInvalidLevel;
+  }
+
+  bool supports_per_key_placement =
+      immutable_options.preclude_last_level_data_seconds > 0;
+
+  // it could be overridden by unittest
+  TEST_SYNC_POINT_CALLBACK("Compaction::SupportsPerKeyPlacement:Enabled",
+                           &supports_per_key_placement);
+  if (!supports_per_key_placement) {
+    return kInvalidLevel;
+  }
+
+  return penultimate_level;
+}
+
+}  // namespace ROCKSDB_NAMESPACE