Add BlockBasedTableOptions::index_block_restart_interval

Summary: Add a new option to BlockBasedTableOptions that will allow us to change the restart interval for the index block

Test Plan: unit tests

Reviewers: yhchiang, anthony, andrewkr, sdong

Reviewed By: sdong

Subscribers: march, dhruba

Differential Revision: https://reviews.facebook.net/D53721

db/db_test.cc

@@ -5272,6 +5272,7 @@ class DBTestRandomized : public DBTest,
         option_configs.push_back(option_config);
       }
     }
+    option_configs.push_back(kBlockBasedTableWithIndexRestartInterval);
     return option_configs;
   }
 };

db/db_test_util.cc

@@ -339,6 +339,10 @@ Options DBTestBase::CurrentOptions(
       options.prefix_extractor.reset(NewNoopTransform());
       break;
     }
+    case kBlockBasedTableWithIndexRestartInterval: {
+      table_options.index_block_restart_interval = 8;
+      break;
+    }
     case kOptimizeFiltersForHits: {
       options.optimize_filters_for_hits = true;
       set_block_based_table_factory = true;

db/db_test_util.h

@@ -529,6 +529,7 @@ class DBTestBase : public testing::Test {
     kEnd = 31,
     kLevelSubcompactions = 31,
     kUniversalSubcompactions = 32,
+    kBlockBasedTableWithIndexRestartInterval = 33,
   };
   int option_config_;
 

include/rocksdb/table.h

@@ -120,6 +120,9 @@ struct BlockBasedTableOptions {
   // value will be silently overwritten with 1.
   int block_restart_interval = 16;
 
+  // Same as block_restart_interval but used for the index block.
+  int index_block_restart_interval = 1;
+
   // Use delta encoding to compress keys in blocks.
   // Iterator::PinData() requires this option to be disabled.
   //

table/block_based_table_builder.cc

@@ -113,15 +113,17 @@ class IndexBuilder {
 //
 // Optimizations:
 //  1. Made block's `block_restart_interval` to be 1, which will avoid linear
-//     search when doing index lookup.
+//     search when doing index lookup (can be disabled by setting
+//     index_block_restart_interval).
 //  2. Shorten the key length for index block. Other than honestly using the
 //     last key in the data block as the index key, we instead find a shortest
 //     substitute key that serves the same function.
 class ShortenedIndexBuilder : public IndexBuilder {
  public:
-  explicit ShortenedIndexBuilder(const Comparator* comparator)
+  explicit ShortenedIndexBuilder(const Comparator* comparator,
+                                 int index_block_restart_interval)
       : IndexBuilder(comparator),
-        index_block_builder_(1 /* block_restart_interval == 1 */) {}
+        index_block_builder_(index_block_restart_interval) {}
 
   virtual void AddIndexEntry(std::string* last_key_in_current_block,
                              const Slice* first_key_in_next_block,
@@ -178,9 +180,10 @@ class ShortenedIndexBuilder : public IndexBuilder {
 class HashIndexBuilder : public IndexBuilder {
  public:
   explicit HashIndexBuilder(const Comparator* comparator,
-                            const SliceTransform* hash_key_extractor)
+                            const SliceTransform* hash_key_extractor,
+                            int index_block_restart_interval)
       : IndexBuilder(comparator),
-        primary_index_builder_(comparator),
+        primary_index_builder_(comparator, index_block_restart_interval),
         hash_key_extractor_(hash_key_extractor) {}
 
   virtual void AddIndexEntry(std::string* last_key_in_current_block,
@@ -266,13 +269,16 @@ namespace {
 
 // Create a index builder based on its type.
 IndexBuilder* CreateIndexBuilder(IndexType type, const Comparator* comparator,
-                                 const SliceTransform* prefix_extractor) {
+                                 const SliceTransform* prefix_extractor,
+                                 int index_block_restart_interval) {
   switch (type) {
     case BlockBasedTableOptions::kBinarySearch: {
-      return new ShortenedIndexBuilder(comparator);
+      return new ShortenedIndexBuilder(comparator,
+                                       index_block_restart_interval);
     }
     case BlockBasedTableOptions::kHashSearch: {
-      return new HashIndexBuilder(comparator, prefix_extractor);
+      return new HashIndexBuilder(comparator, prefix_extractor,
+                                  index_block_restart_interval);
     }
     default: {
       assert(!"Do not recognize the index type ");
@@ -484,9 +490,10 @@ struct BlockBasedTableBuilder::Rep {
         data_block(table_options.block_restart_interval,
                    table_options.use_delta_encoding),
         internal_prefix_transform(_ioptions.prefix_extractor),
-        index_builder(CreateIndexBuilder(table_options.index_type,
-                                         &internal_comparator,
-                                         &this->internal_prefix_transform)),
+        index_builder(
+            CreateIndexBuilder(table_options.index_type, &internal_comparator,
+                               &this->internal_prefix_transform,
+                               table_options.index_block_restart_interval)),
         compression_type(_compression_type),
         compression_opts(_compression_opts),
         filter_block(skip_filters ? nullptr : CreateFilterBlockBuilder(

table/block_based_table_factory.cc

@@ -42,6 +42,9 @@ BlockBasedTableFactory::BlockBasedTableFactory(
   if (table_options_.block_restart_interval < 1) {
     table_options_.block_restart_interval = 1;
   }
+  if (table_options_.index_block_restart_interval < 1) {
+    table_options_.index_block_restart_interval = 1;
+  }
 }
 
 Status BlockBasedTableFactory::NewTableReader(
@@ -150,6 +153,9 @@ std::string BlockBasedTableFactory::GetPrintableTableOptions() const {
   snprintf(buffer, kBufferSize, "  block_restart_interval: %d\n",
            table_options_.block_restart_interval);
   ret.append(buffer);
+  snprintf(buffer, kBufferSize, "  index_block_restart_interval: %d\n",
+           table_options_.index_block_restart_interval);
+  ret.append(buffer);
   snprintf(buffer, kBufferSize, "  filter_policy: %s\n",
            table_options_.filter_policy == nullptr ?
              "nullptr" : table_options_.filter_policy->Name());

table/table_test.cc

@@ -637,6 +637,7 @@ class HarnessTest : public testing::Test {
             new FlushBlockBySizePolicyFactory());
         table_options_.block_size = 256;
         table_options_.block_restart_interval = args.restart_interval;
+        table_options_.index_block_restart_interval = args.restart_interval;
         table_options_.format_version = args.format_version;
         options_.table_factory.reset(
             new BlockBasedTableFactory(table_options_));
@@ -2282,6 +2283,67 @@ TEST_F(HarnessTest, FooterTests) {
   }
 }
 
+class IndexBlockRestartIntervalTest
+    : public BlockBasedTableTest,
+      public ::testing::WithParamInterface<int> {
+ public:
+  static std::vector<int> GetRestartValues() { return {-1, 0, 1, 8, 16, 32}; }
+};
+
+INSTANTIATE_TEST_CASE_P(
+    IndexBlockRestartIntervalTest, IndexBlockRestartIntervalTest,
+    ::testing::ValuesIn(IndexBlockRestartIntervalTest::GetRestartValues()));
+
+TEST_P(IndexBlockRestartIntervalTest, IndexBlockRestartInterval) {
+  const int kKeysInTable = 10000;
+  const int kKeySize = 100;
+  const int kValSize = 500;
+
+  int index_block_restart_interval = GetParam();
+
+  Options options;
+  BlockBasedTableOptions table_options;
+  table_options.block_size = 64;  // small block size to get big index block
+  table_options.index_block_restart_interval = index_block_restart_interval;
+  options.table_factory.reset(new BlockBasedTableFactory(table_options));
+
+  TableConstructor c(BytewiseComparator());
+  static Random rnd(301);
+  for (int i = 0; i < kKeysInTable; i++) {
+    InternalKey k(RandomString(&rnd, kKeySize), 0, kTypeValue);
+    c.Add(k.Encode().ToString(), RandomString(&rnd, kValSize));
+  }
+
+  std::vector<std::string> keys;
+  stl_wrappers::KVMap kvmap;
+  std::unique_ptr<InternalKeyComparator> comparator(
+      new InternalKeyComparator(BytewiseComparator()));
+  const ImmutableCFOptions ioptions(options);
+  c.Finish(options, ioptions, table_options, *comparator, &keys, &kvmap);
+  auto reader = c.GetTableReader();
+
+  std::unique_ptr<InternalIterator> db_iter(reader->NewIterator(ReadOptions()));
+
+  // Test point lookup
+  for (auto& kv : kvmap) {
+    db_iter->Seek(kv.first);
+
+    ASSERT_TRUE(db_iter->Valid());
+    ASSERT_OK(db_iter->status());
+    ASSERT_EQ(db_iter->key(), kv.first);
+    ASSERT_EQ(db_iter->value(), kv.second);
+  }
+
+  // Test iterating
+  auto kv_iter = kvmap.begin();
+  for (db_iter->SeekToFirst(); db_iter->Valid(); db_iter->Next()) {
+    ASSERT_EQ(db_iter->key(), kv_iter->first);
+    ASSERT_EQ(db_iter->value(), kv_iter->second);
+    kv_iter++;
+  }
+  ASSERT_EQ(kv_iter, kvmap.end());
+}
+
 }  // namespace rocksdb
 
 int main(int argc, char** argv) {

util/options_helper.h

@@ -486,6 +486,9 @@ static std::unordered_map<std::string,
     {"block_restart_interval",
      {offsetof(struct BlockBasedTableOptions, block_restart_interval),
       OptionType::kInt, OptionVerificationType::kNormal}},
+    {"index_block_restart_interval",
+     {offsetof(struct BlockBasedTableOptions, index_block_restart_interval),
+      OptionType::kInt, OptionVerificationType::kNormal}},
     {"filter_policy",
      {offsetof(struct BlockBasedTableOptions, filter_policy),
       OptionType::kFilterPolicy, OptionVerificationType::kByName}},

util/options_test.cc

@@ -1576,6 +1576,7 @@ TEST_F(OptionsParserTest, BlockBasedTableOptionsAllFieldsSettable) {
       "checksum=kxxHash;hash_index_allow_collision=1;no_block_cache=1;"
       "block_cache=1M;block_cache_compressed=1k;block_size=1024;"
       "block_size_deviation=8;block_restart_interval=4; "
+      "index_block_restart_interval=4;"
       "filter_policy=bloomfilter:4:true;whole_key_filtering=1;"
       "skip_table_builder_flush=1;format_version=1;"
       "hash_index_allow_collision=false;",

util/testutil.cc

@@ -200,6 +200,7 @@ BlockBasedTableOptions RandomBlockBasedTableOptions(Random* rnd) {
   opt.block_size = rnd->Uniform(10000000);
   opt.block_size_deviation = rnd->Uniform(100);
   opt.block_restart_interval = rnd->Uniform(100);
+  opt.index_block_restart_interval = rnd->Uniform(100);
   opt.whole_key_filtering = rnd->Uniform(2);
 
   return opt;