Changed 'num_subcompactions' to the more accurate 'max_subcompactions'

Summary:
Up until this point we had DbOptions.num_subcompactions, but
it is semantically more correct to call this max_subcompactions since
we will schedule *up to* DbOptions.max_subcompactions smaller compactions
at a time during a compaction job.

I also added a --subcompactions option to db_bench

Test Plan: make all   make check

Reviewers: sdong, igor, anthony, yhchiang

Reviewed By: yhchiang

Subscribers: dhruba

Differential Revision: https://reviews.facebook.net/D45069

HISTORY.md

@@ -4,6 +4,7 @@
 
 ### Public API Changes
 * Removed class Env::RandomRWFile and Env::NewRandomRWFile().
+* Renamed DBOptions.num_subcompactions to DBOptions.max_subcompactions to make the name better match the actual funcionality of the option.
 
 ## 3.13.0 (8/6/2015)
 ### New Features

db/compaction.h

@@ -200,13 +200,13 @@ class Compaction {
 
   // Should this compaction be broken up into smaller ones run in parallel?
   bool IsSubCompaction() const {
-    return start_level_ == 0 && output_level_ == 1
+    return start_level_ == 0 && output_level_ == 1 &&
-        && mutable_cf_options_.num_subcompactions > 1;
+           mutable_cf_options_.max_subcompactions > 1;
   }
 
   // If is_sub_compaction == true, how many smaller compactions should execute
   int NumSubCompactions() const {
-    return mutable_cf_options_.num_subcompactions;
+    return mutable_cf_options_.max_subcompactions;
   }
 
  private:

db/compaction_job.cc

@@ -380,13 +380,13 @@ void CompactionJob::InitializeSubCompactions(const SequenceNumber& earliest,
           }
 
           // Divide the potential L1 file boundaries (those that passed the
-          // checks above) into 'num_subcompactions' groups such that each have
+          // checks above) into 'max_subcompactions' groups such that each have
           // as close to an equal number of files in it as possible
           // TODO(aekmekji): refine this later to depend on file size
           size_t files_left = candidates.size();
           size_t subcompactions_left =
-              static_cast<size_t>(db_options_.num_subcompactions) < files_left
+              static_cast<size_t>(db_options_.max_subcompactions) < files_left
-                  ? db_options_.num_subcompactions
+                  ? db_options_.max_subcompactions
                   : files_left;
 
           size_t num_to_include;

db/compaction_job_stats_test.cc

@@ -92,7 +92,7 @@ class CompactionJobStatsTest : public testing::Test,
   Env* env_;
   DB* db_;
   std::vector<ColumnFamilyHandle*> handles_;
-  uint32_t num_subcompactions_;
+  uint32_t max_subcompactions_;
 
   Options last_options_;
 
@@ -103,8 +103,8 @@ class CompactionJobStatsTest : public testing::Test,
     alternative_wal_dir_ = dbname_ + "/wal";
     Options options;
     options.create_if_missing = true;
-    num_subcompactions_ = GetParam();
+    max_subcompactions_ = GetParam();
-    options.num_subcompactions = num_subcompactions_;
+    options.max_subcompactions = max_subcompactions_;
     auto delete_options = options;
     delete_options.wal_dir = alternative_wal_dir_;
     EXPECT_OK(DestroyDB(dbname_, delete_options));
@@ -656,7 +656,7 @@ TEST_P(CompactionJobStatsTest, CompactionJobStatsTest) {
   options.level0_file_num_compaction_trigger = kTestScale + 1;
   options.num_levels = 3;
   options.compression = kNoCompression;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   options.bytes_per_sync = 512 * 1024;
 
   options.compaction_measure_io_stats = true;
@@ -740,7 +740,7 @@ TEST_P(CompactionJobStatsTest, CompactionJobStatsTest) {
     // by 1 because multiple threads are consuming the input and generating
     // output files without coordinating to see if the output could fit into
     // a smaller number of files like it does when it runs sequentially
-    int num_output_files = options.num_subcompactions > 1 ? 2 : 1;
+    int num_output_files = options.max_subcompactions > 1 ? 2 : 1;
     for (uint64_t start_key = key_base;
          num_L0_files > 1;
          start_key += key_base * sparseness) {
@@ -760,7 +760,7 @@ TEST_P(CompactionJobStatsTest, CompactionJobStatsTest) {
       Compact(1, smallest_key, largest_key);
       // TODO(aekmekji): account for whether parallel L0-L1 compaction is
       // enabled or not. If so then num_L1_files will increase by 1
-      if (options.num_subcompactions == 1) {
+      if (options.max_subcompactions == 1) {
         --num_L1_files;
       }
       snprintf(buf, kBufSize, "%d,%d", --num_L0_files, num_L1_files);
@@ -783,7 +783,7 @@ TEST_P(CompactionJobStatsTest, CompactionJobStatsTest) {
     ASSERT_EQ(stats_checker->NumberOfUnverifiedStats(), 1U);
     Compact(1, smallest_key, largest_key);
 
-    num_L1_files = options.num_subcompactions > 1 ? 7 : 4;
+    num_L1_files = options.max_subcompactions > 1 ? 7 : 4;
     char L1_buf[4];
     snprintf(L1_buf, sizeof(L1_buf), "0,%d", num_L1_files);
     std::string L1_files(L1_buf);
@@ -880,7 +880,7 @@ TEST_P(CompactionJobStatsTest, DeletionStatsTest) {
   options.num_levels = 3;
   options.compression = kNoCompression;
   options.max_bytes_for_level_multiplier = 2;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
 
   DestroyAndReopen(options);
   CreateAndReopenWithCF({"pikachu"}, options);
@@ -972,7 +972,7 @@ TEST_P(CompactionJobStatsTest, UniversalCompactionTest) {
   options.compaction_style = kCompactionStyleUniversal;
   options.compaction_options_universal.size_ratio = 1;
   options.compaction_options_universal.max_size_amplification_percent = 1000;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
 
   DestroyAndReopen(options);
   CreateAndReopenWithCF({"pikachu"}, options);

db/db_bench.cc

@@ -221,6 +221,17 @@ static bool ValidateKeySize(const char* flagname, int32_t value) {
   return true;
 }
 
+static bool ValidateUint32Range(const char* flagname, uint64_t value) {
+  if (value > std::numeric_limits<uint32_t>::max()) {
+    fprintf(stderr,
+            "Invalid value for --%s: %lu, overflow\n",
+            flagname,
+            (unsigned long)value);
+    return false;
+  }
+  return true;
+}
+
 DEFINE_int32(key_size, 16, "size of each key");
 
 DEFINE_int32(num_multi_db, 0,
@@ -286,6 +297,12 @@ DEFINE_int32(max_background_compactions,
              "The maximum number of concurrent background compactions"
              " that can occur in parallel.");
 
+DEFINE_uint64(subcompactions, 1,
+             "Maximum number of subcompactions to divide L0-L1 compactions "
+             "into.");
+static const bool FLAGS_subcompactions_dummy __attribute__((unused)) =
+    RegisterFlagValidator(&FLAGS_subcompactions, &ValidateUint32Range);
+
 DEFINE_int32(max_background_flushes,
              rocksdb::Options().max_background_flushes,
              "The maximum number of concurrent background flushes"
@@ -2158,6 +2175,7 @@ class Benchmark {
     options.max_write_buffer_number_to_maintain =
         FLAGS_max_write_buffer_number_to_maintain;
     options.max_background_compactions = FLAGS_max_background_compactions;
+    options.max_subcompactions = static_cast<uint32_t>(FLAGS_subcompactions);
     options.max_background_flushes = FLAGS_max_background_flushes;
     options.compaction_style = FLAGS_compaction_style_e;
     if (FLAGS_prefix_size != 0) {

db/db_compaction_test.cc

@@ -26,14 +26,14 @@ class DBCompactionTestWithParam : public DBTestBase,
                                 public testing::WithParamInterface<uint32_t> {
  public:
   DBCompactionTestWithParam() : DBTestBase("/db_compaction_test") {
-    num_subcompactions_ = GetParam();
+    max_subcompactions_ = GetParam();
   }
 
   // Required if inheriting from testing::WithParamInterface<>
   static void SetUpTestCase() {}
   static void TearDownTestCase() {}
 
-  uint32_t num_subcompactions_;
+  uint32_t max_subcompactions_;
 };
 
 namespace {
@@ -214,12 +214,12 @@ const SstFileMetaData* PickFileRandomly(
 }  // anonymous namespace
 
 // All the TEST_P tests run once with sub_compactions disabled (i.e.
-// options.num_subcompactions = 1) and once with it enabled
+// options.max_subcompactions = 1) and once with it enabled
 TEST_P(DBCompactionTestWithParam, CompactionDeletionTrigger) {
   for (int tid = 0; tid < 3; ++tid) {
     uint64_t db_size[2];
     Options options = CurrentOptions(DeletionTriggerOptions());
-    options.num_subcompactions = num_subcompactions_;
+    options.max_subcompactions = max_subcompactions_;
 
     if (tid == 1) {
       // the following only disable stats update in DB::Open()
@@ -392,7 +392,7 @@ TEST_P(DBCompactionTestWithParam, CompactionDeletionTriggerReopen) {
   for (int tid = 0; tid < 2; ++tid) {
     uint64_t db_size[3];
     Options options = CurrentOptions(DeletionTriggerOptions());
-    options.num_subcompactions = num_subcompactions_;
+    options.max_subcompactions = max_subcompactions_;
 
     if (tid == 1) {
       // second pass with universal compaction
@@ -508,7 +508,7 @@ TEST_P(DBCompactionTestWithParam, CompactionTrigger) {
   options.write_buffer_size = 100 << 10;  // 100KB
   options.num_levels = 3;
   options.level0_file_num_compaction_trigger = 3;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   options = CurrentOptions(options);
   CreateAndReopenWithCF({"pikachu"}, options);
 
@@ -541,7 +541,7 @@ TEST_P(DBCompactionTestWithParam, CompactionTrigger) {
 TEST_P(DBCompactionTestWithParam, CompactionsGenerateMultipleFiles) {
   Options options;
   options.write_buffer_size = 100000000;        // Large write buffer
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   options = CurrentOptions(options);
   CreateAndReopenWithCF({"pikachu"}, options);
 
@@ -628,7 +628,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveOneFile) {
 
   Options options;
   options.write_buffer_size = 100000000;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   options = CurrentOptions(options);
   DestroyAndReopen(options);
 
@@ -687,7 +687,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveNonOverlappingFiles) {
   Options options = CurrentOptions();
   options.disable_auto_compactions = true;
   options.write_buffer_size = 10 * 1024 * 1024;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
 
   DestroyAndReopen(options);
   // non overlapping ranges
@@ -784,7 +784,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveTargetLevel) {
   options.disable_auto_compactions = true;
   options.write_buffer_size = 10 * 1024 * 1024;
   options.num_levels = 7;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
 
   DestroyAndReopen(options);
   int32_t value_size = 10 * 1024;  // 10 KB
@@ -840,7 +840,7 @@ TEST_P(DBCompactionTestWithParam, TrivialMoveToLastLevelWithFiles) {
 
   Options options;
   options.write_buffer_size = 100000000;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   options = CurrentOptions(options);
   DestroyAndReopen(options);
 
@@ -896,7 +896,7 @@ TEST_P(DBCompactionTestWithParam, LevelCompactionThirdPath) {
   options.level0_file_num_compaction_trigger = 2;
   options.num_levels = 4;
   options.max_bytes_for_level_base = 400 * 1024;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   //  options = CurrentOptions(options);
 
   std::vector<std::string> filenames;
@@ -1010,7 +1010,7 @@ TEST_P(DBCompactionTestWithParam, LevelCompactionPathUse) {
   options.level0_file_num_compaction_trigger = 2;
   options.num_levels = 4;
   options.max_bytes_for_level_base = 400 * 1024;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   //  options = CurrentOptions(options);
 
   std::vector<std::string> filenames;
@@ -1129,7 +1129,7 @@ TEST_P(DBCompactionTestWithParam, ConvertCompactionStyle) {
   options.max_bytes_for_level_multiplier = 1;
   options.target_file_size_base = 200 << 10;  // 200KB
   options.target_file_size_multiplier = 1;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   options = CurrentOptions(options);
   CreateAndReopenWithCF({"pikachu"}, options);
 
@@ -1267,7 +1267,7 @@ TEST_F(DBCompactionTest, L0_CompactionBug_Issue44_b) {
 
 TEST_P(DBCompactionTestWithParam, ManualCompaction) {
   Options options = CurrentOptions();
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   CreateAndReopenWithCF({"pikachu"}, options);
 
   // iter - 0 with 7 levels
@@ -1319,7 +1319,7 @@ TEST_P(DBCompactionTestWithParam, ManualLevelCompactionOutputPathId) {
   options.db_paths.emplace_back(dbname_ + "_2", 2 * 10485760);
   options.db_paths.emplace_back(dbname_ + "_3", 100 * 10485760);
   options.db_paths.emplace_back(dbname_ + "_4", 120 * 10485760);
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   CreateAndReopenWithCF({"pikachu"}, options);
 
   // iter - 0 with 7 levels
@@ -1423,7 +1423,7 @@ TEST_P(DBCompactionTestWithParam, DISABLED_CompactFilesOnLevelCompaction) {
   options.level0_stop_writes_trigger = 2;
   options.max_bytes_for_level_multiplier = 2;
   options.compression = kNoCompression;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   options = CurrentOptions(options);
   CreateAndReopenWithCF({"pikachu"}, options);
 
@@ -1483,7 +1483,7 @@ TEST_P(DBCompactionTestWithParam, PartialCompactionFailure) {
       options.target_file_size_base;
   options.max_bytes_for_level_multiplier = 2;
   options.compression = kNoCompression;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
 
   env_->SetBackgroundThreads(1, Env::HIGH);
   env_->SetBackgroundThreads(1, Env::LOW);
@@ -1564,7 +1564,7 @@ TEST_P(DBCompactionTestWithParam, DeleteMovedFileAfterCompaction) {
         2;  // trigger compaction when we have 2 files
     OnFileDeletionListener* listener = new OnFileDeletionListener();
     options.listeners.emplace_back(listener);
-    options.num_subcompactions = num_subcompactions_;
+    options.max_subcompactions = max_subcompactions_;
     DestroyAndReopen(options);
 
     Random rnd(301);
@@ -1638,7 +1638,7 @@ TEST_P(DBCompactionTestWithParam, CompressLevelCompaction) {
   options.level0_file_num_compaction_trigger = 2;
   options.num_levels = 4;
   options.max_bytes_for_level_base = 400 * 1024;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   // First two levels have no compression, so that a trivial move between
   // them will be allowed. Level 2 has Zlib compression so that a trivial
   // move to level 3 will not be allowed
@@ -1751,7 +1751,7 @@ TEST_P(DBCompactionTestWithParam, SuggestCompactRangeNoTwoLevel0Compactions) {
   options.target_file_size_base = 98 << 10;
   options.max_write_buffer_number = 2;
   options.max_background_compactions = 2;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
 
   DestroyAndReopen(options);
 
@@ -1808,7 +1808,7 @@ TEST_P(DBCompactionTestWithParam, ForceBottommostLevelCompaction) {
 
   Options options;
   options.write_buffer_size = 100000000;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   options = CurrentOptions(options);
   DestroyAndReopen(options);
 

db/db_test.cc

@@ -120,15 +120,13 @@ class DBTest : public DBTestBase {
 class DBTestWithParam : public DBTest,
                         public testing::WithParamInterface<uint32_t> {
  public:
-  DBTestWithParam() {
+  DBTestWithParam() { max_subcompactions_ = GetParam(); }
-    num_subcompactions_ = GetParam();
-  }
 
   // Required if inheriting from testing::WithParamInterface<>
   static void SetUpTestCase() {}
   static void TearDownTestCase() {}
 
-  uint32_t num_subcompactions_;
+  uint32_t max_subcompactions_;
 };
 
 TEST_F(DBTest, Empty) {
@@ -5745,7 +5743,7 @@ TEST_P(DBTestWithParam, FIFOCompactionTest) {
     options.compaction_options_fifo.max_table_files_size = 500 << 10;  // 500KB
     options.compression = kNoCompression;
     options.create_if_missing = true;
-    options.num_subcompactions = num_subcompactions_;
+    options.max_subcompactions = max_subcompactions_;
     if (iter == 1) {
       options.disable_auto_compactions = true;
     }
@@ -6389,7 +6387,7 @@ TEST_P(DBTestWithParam, ThreadStatusSingleCompaction) {
   options.enable_thread_tracking = true;
   const int kNumL0Files = 4;
   options.level0_file_num_compaction_trigger = kNumL0Files;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
 
   rocksdb::SyncPoint::GetInstance()->LoadDependency({
       {"DBTest::ThreadStatusSingleCompaction:0", "DBImpl::BGWorkCompaction"},
@@ -6438,7 +6436,7 @@ TEST_P(DBTestWithParam, ThreadStatusSingleCompaction) {
 TEST_P(DBTestWithParam, PreShutdownManualCompaction) {
   Options options = CurrentOptions();
   options.max_background_flushes = 0;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   CreateAndReopenWithCF({"pikachu"}, options);
 
   // iter - 0 with 7 levels
@@ -6524,7 +6522,7 @@ TEST_P(DBTestWithParam, PreShutdownMultipleCompaction) {
   options.max_background_compactions = kLowPriCount;
   options.level0_stop_writes_trigger = 1 << 10;
   options.level0_slowdown_writes_trigger = 1 << 10;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
 
   TryReopen(options);
   Random rnd(301);
@@ -6613,7 +6611,7 @@ TEST_P(DBTestWithParam, PreShutdownCompactionMiddle) {
   options.max_background_compactions = kLowPriCount;
   options.level0_stop_writes_trigger = 1 << 10;
   options.level0_slowdown_writes_trigger = 1 << 10;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
 
   TryReopen(options);
   Random rnd(301);
@@ -6938,7 +6936,7 @@ TEST_P(DBTestWithParam, DynamicCompactionOptions) {
   options.target_file_size_multiplier = 1;
   options.max_bytes_for_level_base = k128KB;
   options.max_bytes_for_level_multiplier = 4;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
 
   // Block flush thread and disable compaction thread
   env_->SetBackgroundThreads(1, Env::LOW);
@@ -7670,7 +7668,7 @@ TEST_P(DBTestWithParam, MergeCompactionTimeTest) {
   options.statistics = rocksdb::CreateDBStatistics();
   options.merge_operator.reset(new DelayedMergeOperator(this));
   options.compaction_style = kCompactionStyleUniversal;
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   DestroyAndReopen(options);
 
   for (int i = 0; i < 1000; i++) {
@@ -7690,7 +7688,7 @@ TEST_P(DBTestWithParam, FilterCompactionTimeTest) {
   options.disable_auto_compactions = true;
   options.create_if_missing = true;
   options.statistics = rocksdb::CreateDBStatistics();
-  options.num_subcompactions = num_subcompactions_;
+  options.max_subcompactions = max_subcompactions_;
   options = CurrentOptions(options);
   DestroyAndReopen(options);
 

include/rocksdb/options.h

@@ -908,7 +908,7 @@ struct DBOptions {
   // into multiple, smaller ones that are run simultaneously. This is still
   // under development and is only available for level-based compaction.
   // Default: 1
-  uint32_t num_subcompactions;
+  uint32_t max_subcompactions;
 
   // Maximum number of concurrent background memtable flush jobs, submitted to
   // the HIGH priority thread pool.

tools/db_stress.cc

@@ -1883,7 +1883,7 @@ class StressTest {
     options_.max_manifest_file_size = 10 * 1024;
     options_.filter_deletes = FLAGS_filter_deletes;
     options_.inplace_update_support = FLAGS_in_place_update;
-    options_.num_subcompactions = static_cast<uint32_t>(FLAGS_subcompactions);
+    options_.max_subcompactions = static_cast<uint32_t>(FLAGS_subcompactions);
     if ((FLAGS_prefix_size == 0) == (FLAGS_rep_factory == kHashSkipList)) {
       fprintf(stderr,
             "prefix_size should be non-zero iff memtablerep == prefix_hash\n");

util/db_test_util.cc

@@ -152,7 +152,7 @@ bool DBTestBase::ChangeCompactOptions() {
     option_config_ = kLevelSubcompactions;
     Destroy(last_options_);
     auto options = CurrentOptions();
-    options.num_subcompactions = 4;
+    options.max_subcompactions = 4;
     TryReopen(options);
     return true;
   } else {
@@ -312,7 +312,7 @@ Options DBTestBase::CurrentOptions(
       break;
     }
     case kLevelSubcompactions: {
-      options.num_subcompactions = 2;
+      options.max_subcompactions = 2;
       break;
     }
 

util/mutable_cf_options.h

@@ -40,7 +40,7 @@ struct MutableCFOptions {
         max_bytes_for_level_multiplier_additional(
             options.max_bytes_for_level_multiplier_additional),
         verify_checksums_in_compaction(options.verify_checksums_in_compaction),
-        num_subcompactions(options.num_subcompactions),
+        max_subcompactions(options.max_subcompactions),
         max_sequential_skip_in_iterations(
             options.max_sequential_skip_in_iterations),
         paranoid_file_checks(options.paranoid_file_checks),
@@ -73,7 +73,7 @@ struct MutableCFOptions {
         max_bytes_for_level_base(0),
         max_bytes_for_level_multiplier(0),
         verify_checksums_in_compaction(false),
-        num_subcompactions(1),
+        max_subcompactions(1),
         max_sequential_skip_in_iterations(0),
         paranoid_file_checks(false),
         compaction_measure_io_stats(false) {}
@@ -125,7 +125,7 @@ struct MutableCFOptions {
   int max_bytes_for_level_multiplier;
   std::vector<int> max_bytes_for_level_multiplier_additional;
   bool verify_checksums_in_compaction;
-  int num_subcompactions;
+  int max_subcompactions;
 
   // Misc options
   uint64_t max_sequential_skip_in_iterations;

util/options.cc

@@ -221,7 +221,7 @@ DBOptions::DBOptions()
       wal_dir(""),
       delete_obsolete_files_period_micros(6 * 60 * 60 * 1000000UL),
       max_background_compactions(1),
-      num_subcompactions(1),
+      max_subcompactions(1),
       max_background_flushes(1),
       max_log_file_size(0),
       log_file_time_to_roll(0),
@@ -273,7 +273,7 @@ DBOptions::DBOptions(const Options& options)
       delete_obsolete_files_period_micros(
           options.delete_obsolete_files_period_micros),
       max_background_compactions(options.max_background_compactions),
-      num_subcompactions(options.num_subcompactions),
+      max_subcompactions(options.max_subcompactions),
       max_background_flushes(options.max_background_flushes),
       max_log_file_size(options.max_log_file_size),
       log_file_time_to_roll(options.log_file_time_to_roll),

util/options_helper.h

@@ -114,8 +114,8 @@ static std::unordered_map<std::string, OptionTypeInfo> db_options_type_info = {
     {"db_log_dir",
      {offsetof(struct DBOptions, db_log_dir), OptionType::kString}},
     {"wal_dir", {offsetof(struct DBOptions, wal_dir), OptionType::kString}},
-    {"num_subcompactions",
+    {"max_subcompactions",
-     {offsetof(struct DBOptions, num_subcompactions), OptionType::kUInt32T}},
+     {offsetof(struct DBOptions, max_subcompactions), OptionType::kUInt32T}},
     {"WAL_size_limit_MB",
      {offsetof(struct DBOptions, WAL_size_limit_MB), OptionType::kUInt64T}},
     {"WAL_ttl_seconds",

util/options_test.cc

@@ -552,7 +552,7 @@ void VerifyDBOptions(const DBOptions& base_opt, const DBOptions& new_opt) {
   ASSERT_EQ(base_opt.wal_dir, new_opt.wal_dir);
 
   // uint32_t options
-  ASSERT_EQ(base_opt.num_subcompactions, new_opt.num_subcompactions);
+  ASSERT_EQ(base_opt.max_subcompactions, new_opt.max_subcompactions);
 
   // uint64_t options
   ASSERT_EQ(base_opt.WAL_size_limit_MB, new_opt.WAL_size_limit_MB);
@@ -611,7 +611,7 @@ TEST_F(OptionsTest, DBOptionsSerialization) {
   base_options.wal_dir = "path/to/wal_dir";
 
   // uint32_t options
-  base_options.num_subcompactions = rnd.Uniform(100000);
+  base_options.max_subcompactions = rnd.Uniform(100000);
 
   // uint64_t options
   static const uint64_t uint_max = static_cast<uint64_t>(UINT_MAX);