Configure index partition size

Summary:
Allow the users to specify the target index partition size.

With this patch an index partition is cut before its estimated in-memory size goes above the configured value for metadata_block_size. The filter partitions are still cut right after an index partition is cut.
Closes https://github.com/facebook/rocksdb/pull/2041

Differential Revision: D4780216

Pulled By: maysamyabandeh

fbshipit-source-id: 95a0831

db/db_bloom_filter_test.cc

@@ -50,7 +50,7 @@ TEST_P(DBBloomFilterTestWithParam, KeyMayExist) {
     options_override.filter_policy.reset(
         NewBloomFilterPolicy(20, use_block_based_filter_));
     options_override.partition_filters = partition_filters_;
-    options_override.index_per_partition = 2;
+    options_override.metadata_block_size = 32;
     Options options = CurrentOptions(options_override);
     if (partition_filters_ &&
         static_cast<BlockBasedTableOptions*>(
@@ -334,7 +334,7 @@ TEST_P(DBBloomFilterTestWithParam, BloomFilter) {
       table_options.index_type =
           BlockBasedTableOptions::IndexType::kTwoLevelIndexSearch;
     }
-    table_options.index_per_partition = 2;
+    table_options.metadata_block_size = 32;
     options.table_factory.reset(NewBlockBasedTableFactory(table_options));
 
     CreateAndReopenWithCF({"pikachu"}, options);

db/db_test_util.cc

@@ -437,7 +437,7 @@ Options DBTestBase::CurrentOptions(
   if (options_override.filter_policy) {
     table_options.filter_policy = options_override.filter_policy;
     table_options.partition_filters = options_override.partition_filters;
-    table_options.index_per_partition = options_override.index_per_partition;
+    table_options.metadata_block_size = options_override.metadata_block_size;
   }
   if (set_block_based_table_factory) {
     options.table_factory.reset(NewBlockBasedTableFactory(table_options));

db/db_test_util.h

@@ -111,7 +111,7 @@ struct OptionsOverride {
   std::shared_ptr<const FilterPolicy> filter_policy = nullptr;
   // These will be used only if filter_policy is set
   bool partition_filters = false;
-  uint64_t index_per_partition = 1024;
+  uint64_t metadata_block_size = 1024;
   BlockBasedTableOptions::IndexType index_type =
       BlockBasedTableOptions::IndexType::kBinarySearch;
 

include/rocksdb/flush_block_policy.h

@@ -55,6 +55,10 @@ class FlushBlockBySizePolicyFactory : public FlushBlockPolicyFactory {
   virtual FlushBlockPolicy* NewFlushBlockPolicy(
       const BlockBasedTableOptions& table_options,
       const BlockBuilder& data_block_builder) const override;
+
+  static FlushBlockPolicy* NewFlushBlockPolicy(
+      const uint64_t size, const int deviation,
+      const BlockBuilder& data_block_builder);
 };
 
 }  // rocksdb

include/rocksdb/table.h

@@ -144,9 +144,16 @@ struct BlockBasedTableOptions {
   // Same as block_restart_interval but used for the index block.
   int index_block_restart_interval = 1;
 
-  // Number of index keys per partition of indexes in a multi-level index
-  // i.e., the number of data blocks covered by each index partition
-  uint64_t index_per_partition = 1024;
+  // Block size for partitioned metadata. Currently applied to indexes when
+  // kTwoLevelIndexSearch is used and to filters when partition_filters is used.
+  // Note: Since in the current implementation the filters and index partitions
+  // are aligned, an index/filter block is created when eitehr index or filter
+  // block size reaches the specified limit.
+  // Note: this limit is currently applied to only index blocks; a filter
+  // partition is cut right after an index block is cut
+  // TODO(myabandeh): remove the note above when filter partitions are cut
+  // separately
+  uint64_t metadata_block_size = 4096;
 
   // Note: currently this option requires kTwoLevelIndexSearch to be set as
   // well.

table/flush_block_policy.cc

@@ -71,4 +71,10 @@ FlushBlockPolicy* FlushBlockBySizePolicyFactory::NewFlushBlockPolicy(
       data_block_builder);
 }
 
+FlushBlockPolicy* FlushBlockBySizePolicyFactory::NewFlushBlockPolicy(
+    const uint64_t size, const int deviation,
+    const BlockBuilder& data_block_builder) {
+  return new FlushBlockBySizePolicy(size, deviation, data_block_builder);
+}
+
 }  // namespace rocksdb

table/index_builder.cc

@@ -15,6 +15,7 @@
 #include <string>
 
 #include "rocksdb/comparator.h"
+#include "rocksdb/flush_block_policy.h"
 #include "table/format.h"
 #include "table/partitioned_filter_block.h"
 
@@ -60,32 +61,60 @@ PartitionedIndexBuilder::PartitionedIndexBuilder(
     const BlockBasedTableOptions& table_opt)
     : IndexBuilder(comparator),
       index_block_builder_(table_opt.index_block_restart_interval),
-      table_opt_(table_opt) {
-  sub_index_builder_ = IndexBuilder::CreateIndexBuilder(sub_type_, comparator_,
-                                                        nullptr, table_opt_);
-}
+      sub_index_builder_(nullptr),
+      table_opt_(table_opt) {}
 
 PartitionedIndexBuilder::~PartitionedIndexBuilder() {
   delete sub_index_builder_;
 }
 
+void PartitionedIndexBuilder::MakeNewSubIndexBuilder() {
+  assert(sub_index_builder_ == nullptr);
+  sub_index_builder_ = new ShortenedIndexBuilder(
+      comparator_, table_opt_.index_block_restart_interval);
+  flush_policy_.reset(FlushBlockBySizePolicyFactory::NewFlushBlockPolicy(
+      table_opt_.metadata_block_size, table_opt_.block_size_deviation,
+      sub_index_builder_->index_block_builder_));
+}
+
 void PartitionedIndexBuilder::AddIndexEntry(
     std::string* last_key_in_current_block,
     const Slice* first_key_in_next_block, const BlockHandle& block_handle) {
-  sub_index_builder_->AddIndexEntry(last_key_in_current_block,
-                                    first_key_in_next_block, block_handle);
-  num_indexes++;
+  // Note: to avoid two consecuitive flush in the same method call, we do not
+  // check flush policy when adding the last key
   if (UNLIKELY(first_key_in_next_block == nullptr)) {  // no more keys
-    entries_.push_back({std::string(*last_key_in_current_block),
-                        std::unique_ptr<IndexBuilder>(sub_index_builder_)});
+    if (sub_index_builder_ == nullptr) {
+      MakeNewSubIndexBuilder();
+    }
+    sub_index_builder_->AddIndexEntry(last_key_in_current_block,
+                                      first_key_in_next_block, block_handle);
+    sub_index_last_key_ = std::string(*last_key_in_current_block);
+    entries_.push_back(
+        {sub_index_last_key_,
+         std::unique_ptr<ShortenedIndexBuilder>(sub_index_builder_)});
     sub_index_builder_ = nullptr;
     cut_filter_block = true;
-  } else if (num_indexes % table_opt_.index_per_partition == 0) {
-    entries_.push_back({std::string(*last_key_in_current_block),
-                        std::unique_ptr<IndexBuilder>(sub_index_builder_)});
-    sub_index_builder_ = IndexBuilder::CreateIndexBuilder(
-        sub_type_, comparator_, nullptr, table_opt_);
-    cut_filter_block = true;
+  } else {
+    // apply flush policy only to non-empty sub_index_builder_
+    if (sub_index_builder_ != nullptr) {
+      std::string handle_encoding;
+      block_handle.EncodeTo(&handle_encoding);
+      bool do_flush =
+          flush_policy_->Update(*last_key_in_current_block, handle_encoding);
+      if (do_flush) {
+        entries_.push_back(
+            {sub_index_last_key_,
+             std::unique_ptr<ShortenedIndexBuilder>(sub_index_builder_)});
+        cut_filter_block = true;
+        sub_index_builder_ = nullptr;
+      }
+    }
+    if (sub_index_builder_ == nullptr) {
+      MakeNewSubIndexBuilder();
+    }
+    sub_index_builder_->AddIndexEntry(last_key_in_current_block,
+                                      first_key_in_next_block, block_handle);
+    sub_index_last_key_ = std::string(*last_key_in_current_block);
   }
 }
 

table/index_builder.h

@@ -134,6 +134,7 @@ class ShortenedIndexBuilder : public IndexBuilder {
     index_block_builder_.Add(*last_key_in_current_block, handle_encoding);
   }
 
+  using IndexBuilder::Finish;
   virtual Status Finish(
       IndexBlocks* index_blocks,
       const BlockHandle& last_partition_block_handle) override {
@@ -145,6 +146,8 @@ class ShortenedIndexBuilder : public IndexBuilder {
     return index_block_builder_.CurrentSizeEstimate();
   }
 
+  friend class PartitionedIndexBuilder;
+
  private:
   BlockBuilder index_block_builder_;
 };
@@ -305,24 +308,26 @@ class PartitionedIndexBuilder : public IndexBuilder {
     return false;
   }
 
-  std::string& GetPartitionKey() { return entries_.back().key; }
+  std::string& GetPartitionKey() { return sub_index_last_key_; }
 
  private:
-  static const BlockBasedTableOptions::IndexType sub_type_ =
-      BlockBasedTableOptions::kBinarySearch;
+  void MakeNewSubIndexBuilder();
+
   struct Entry {
     std::string key;
-    std::unique_ptr<IndexBuilder> value;
+    std::unique_ptr<ShortenedIndexBuilder> value;
   };
   std::list<Entry> entries_;  // list of partitioned indexes and their keys
   BlockBuilder index_block_builder_;  // top-level index builder
-  IndexBuilder* sub_index_builder_;   // the active partition index builder
-  uint64_t num_indexes = 0;
-  bool finishing_indexes =
-      false;  // true if Finish is called once but not complete yet.
+  // the active partition index builder
+  ShortenedIndexBuilder* sub_index_builder_;
+  // the last key in the active partition index builder
+  std::string sub_index_last_key_;
+  std::unique_ptr<FlushBlockPolicy> flush_policy_;
+  // true if Finish is called once but not complete yet.
+  bool finishing_indexes = false;
   const BlockBasedTableOptions& table_opt_;
-  // Filter data
-  bool cut_filter_block =
-      false;  // true if it should cut the next filter partition block
+  // true if it should cut the next filter partition block
+  bool cut_filter_block = false;
 };
 }  // namespace rocksdb

table/partitioned_filter_block_test.cc

@@ -7,6 +7,7 @@
 
 #include "rocksdb/filter_policy.h"
 
+#include "table/index_builder.h"
 #include "table/partitioned_filter_block.h"
 #include "util/coding.h"
 #include "util/hash.h"
@@ -51,6 +52,16 @@ class PartitionedFilterBlockTest : public testing::Test {
   const std::string keys[4] = {"afoo", "bar", "box", "hello"};
   const std::string missing_keys[2] = {"missing", "other"};
 
+  uint64_t MaxIndexSize() {
+    int num_keys = sizeof(keys) / sizeof(*keys);
+    uint64_t max_key_size = 0;
+    for (int i = 1; i < num_keys; i++) {
+      max_key_size = std::max(max_key_size, keys[i].size());
+    }
+    uint64_t max_index_size = num_keys * (max_key_size + 8 /*handle*/);
+    return max_index_size;
+  }
+
   int last_offset = 10;
   BlockHandle Write(const Slice& slice) {
     BlockHandle bh(last_offset + 1, slice.size());
@@ -122,8 +133,7 @@ class PartitionedFilterBlockTest : public testing::Test {
     }
   }
 
-  void TestBlockPerKey() {
-    table_options_.index_per_partition = 1;
+  int TestBlockPerKey() {
     std::unique_ptr<PartitionedIndexBuilder> pib(NewIndexBuilder());
     std::unique_ptr<PartitionedFilterBlockBuilder> builder(
         NewBuilder(pib.get()));
@@ -142,6 +152,7 @@ class PartitionedFilterBlockTest : public testing::Test {
     CutABlock(pib.get(), keys[i]);
 
     VerifyReader(builder.get());
+    return CountNumOfIndexPartitions(pib.get());
   }
 
   void TestBlockPerTwoKeys() {
@@ -201,6 +212,18 @@ class PartitionedFilterBlockTest : public testing::Test {
     Slice slice = Slice(next_key.data(), next_key.size());
     builder->AddIndexEntry(&key, &slice, dont_care_block_handle);
   }
+
+  int CountNumOfIndexPartitions(PartitionedIndexBuilder* builder) {
+    IndexBuilder::IndexBlocks dont_care_ib;
+    BlockHandle dont_care_bh(10, 10);
+    Status s;
+    int cnt = 0;
+    do {
+      s = builder->Finish(&dont_care_ib, dont_care_bh);
+      cnt++;
+    } while (s.IsIncomplete());
+    return cnt - 1;  // 1 is 2nd level index
+  }
 };
 
 TEST_F(PartitionedFilterBlockTest, EmptyBuilder) {
@@ -211,29 +234,40 @@ TEST_F(PartitionedFilterBlockTest, EmptyBuilder) {
 }
 
 TEST_F(PartitionedFilterBlockTest, OneBlock) {
-  int num_keys = sizeof(keys) / sizeof(*keys);
-  for (int i = 1; i < num_keys + 1; i++) {
-    table_options_.index_per_partition = i;
+  uint64_t max_index_size = MaxIndexSize();
+  for (uint64_t i = 1; i < max_index_size + 1; i++) {
+    table_options_.metadata_block_size = i;
     TestBlockPerAllKeys();
   }
 }
 
 TEST_F(PartitionedFilterBlockTest, TwoBlocksPerKey) {
-  int num_keys = sizeof(keys) / sizeof(*keys);
-  for (int i = 1; i < num_keys + 1; i++) {
-    table_options_.index_per_partition = i;
+  uint64_t max_index_size = MaxIndexSize();
+  for (uint64_t i = 1; i < max_index_size + 1; i++) {
+    table_options_.metadata_block_size = i;
     TestBlockPerTwoKeys();
   }
 }
 
 TEST_F(PartitionedFilterBlockTest, OneBlockPerKey) {
-  int num_keys = sizeof(keys) / sizeof(*keys);
-  for (int i = 1; i < num_keys + 1; i++) {
-    table_options_.index_per_partition = i;
+  uint64_t max_index_size = MaxIndexSize();
+  for (uint64_t i = 1; i < max_index_size + 1; i++) {
+    table_options_.metadata_block_size = i;
     TestBlockPerKey();
   }
 }
 
+TEST_F(PartitionedFilterBlockTest, PartitionCount) {
+  int num_keys = sizeof(keys) / sizeof(*keys);
+  table_options_.metadata_block_size = MaxIndexSize();
+  int partitions = TestBlockPerKey();
+  ASSERT_EQ(partitions, 1);
+  // A low number ensures cutting a block after each key
+  table_options_.metadata_block_size = 1;
+  partitions = TestBlockPerKey();
+  ASSERT_EQ(partitions, num_keys - 1 /* last two keys make one flush */);
+}
+
 }  // namespace rocksdb
 
 int main(int argc, char** argv) {

table/table_test.cc

@@ -1657,10 +1657,12 @@ TEST_F(TableTest, HashIndexTest) {
 
 TEST_F(TableTest, PartitionIndexTest) {
   const int max_index_keys = 5;
-  for (int i = 1; i <= max_index_keys + 1; i++) {
+  const int est_max_index_key_value_size = 32;
+  const int est_max_index_size = max_index_keys * est_max_index_key_value_size;
+  for (int i = 1; i <= est_max_index_size + 1; i++) {
     BlockBasedTableOptions table_options;
     table_options.index_type = BlockBasedTableOptions::kTwoLevelIndexSearch;
-    table_options.index_per_partition = i;
+    table_options.metadata_block_size = i;
     IndexTest(table_options);
   }
 }

util/options_helper.h

@@ -636,8 +636,8 @@ static std::unordered_map<std::string, OptionTypeInfo>
         {"index_block_restart_interval",
          {offsetof(struct BlockBasedTableOptions, index_block_restart_interval),
           OptionType::kInt, OptionVerificationType::kNormal, false, 0}},
-        {"index_per_partition",
-         {offsetof(struct BlockBasedTableOptions, index_per_partition),
+        {"metadata_block_size",
+         {offsetof(struct BlockBasedTableOptions, metadata_block_size),
           OptionType::kUInt64T, OptionVerificationType::kNormal, false, 0}},
         {"partition_filters",
          {offsetof(struct BlockBasedTableOptions, partition_filters),

util/options_settable_test.cc

@@ -155,7 +155,7 @@ TEST_F(OptionsSettableTest, 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_per_partition=4;"
+      "metadata_block_size=1024;"
       "partition_filters=false;"
       "index_block_restart_interval=4;"
       "filter_policy=bloomfilter:4:true;whole_key_filtering=1;"