Update Flush policy in PartitionedIndexBuilder on switching from user-key to internal-key mode (#7096)

Summary:
When format_version is high enough to support user-key and
there are index entries for same user key that spans multiple data
blocks then it changes from user-key mode to internal-key mode. But the
flush policy is not reset to point to Block Builder of internal-keys.
After this switch, no entries are added to user key index partition
result, thus it never triggers flushing the block.

Fix: 1. After adding the entry in sub_builder_index_, if there is a switch
from user-key to internal-key, then flush policy is updated to point to
Block Builder of internal-keys index partition.
2. Set sub_builder_index_->seperator_is_key_plus_seq_ = true if
seperator_is_key_plus_seq_  is set to true so that subsequent partitions
can also use internal key mode.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7096

Test Plan: make check -j64

Reviewed By: ajkr

Differential Revision: D22416598

Pulled By: akankshamahajan15

fbshipit-source-id: 01fc2dc07ea1b32f8fb803995ebe6e9a3fbe67ac

HISTORY.md

@@ -13,6 +13,7 @@
 * Compressed block cache was automatically disabled with read-only DBs by mistake. Now it is fixed: compressed block cache will be in effective with read-only DB too.
 * Fix a bug of wrong iterator result if another thread finishes an update and a DB flush between two statement.
 * Disable file deletion after MANIFEST write/sync failure until db re-open or Resume() so that subsequent re-open will not see MANIFEST referencing deleted SSTs.
+* Fix a bug when index_type == kTwoLevelIndexSearch in PartitionedIndexBuilder to update FlushPolicy to point to internal key partitioner when it changes from user-key mode to internal-key mode in index partition.
 
 ### Public API Change
 * `DB::GetDbSessionId(std::string& session_id)` is added. `session_id` stores a unique identifier that gets reset every time the DB is opened. This DB session ID should be unique among all open DB instances on all hosts, and should be unique among re-openings of the same or other DBs. This identifier is recorded in the LOG file on the line starting with "DB Session ID:".

db/db_test2.cc

@@ -144,6 +144,38 @@ INSTANTIATE_TEST_CASE_P(TestReadOnlyWithCompressedCache,
                         TestReadOnlyWithCompressedCache,
                         ::testing::Combine(::testing::Values(-1, 100),
                                            ::testing::Bool()));
+
+class PartitionedIndexTestListener : public EventListener {
+ public:
+  void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
+    ASSERT_GT(info.table_properties.index_partitions, 1);
+    ASSERT_EQ(info.table_properties.index_key_is_user_key, 0);
+  }
+};
+
+TEST_F(DBTest2, PartitionedIndexUserToInternalKey) {
+  BlockBasedTableOptions table_options;
+  Options options = CurrentOptions();
+  table_options.index_type = BlockBasedTableOptions::kTwoLevelIndexSearch;
+  PartitionedIndexTestListener* listener = new PartitionedIndexTestListener();
+  options.table_factory.reset(NewBlockBasedTableFactory(table_options));
+  options.listeners.emplace_back(listener);
+  std::vector<const Snapshot*> snapshots;
+  Reopen(options);
+  Random rnd(301);
+
+  for (int i = 0; i < 3000; i++) {
+    int j = i % 30;
+    std::string value = RandomString(&rnd, 10500);
+    ASSERT_OK(Put("keykey_" + std::to_string(j), value));
+    snapshots.push_back(db_->GetSnapshot());
+  }
+  Flush();
+  for (auto s : snapshots) {
+    db_->ReleaseSnapshot(s);
+  }
+}
+
 #endif  // ROCKSDB_LITE
 
 class PrefixFullBloomWithReverseComparator

table/block_based/index_builder.cc

@@ -104,6 +104,15 @@ void PartitionedIndexBuilder::MakeNewSubIndexBuilder() {
       comparator_, table_opt_.index_block_restart_interval,
       table_opt_.format_version, use_value_delta_encoding_,
       table_opt_.index_shortening, /* include_first_key */ false);
+
+  // Set sub_index_builder_->seperator_is_key_plus_seq_ to true if
+  // seperator_is_key_plus_seq_ is true (internal-key mode) (set to false by
+  // default on Creation) so that flush policy can point to
+  // sub_index_builder_->index_block_builder_
+  if (seperator_is_key_plus_seq_) {
+    sub_index_builder_->seperator_is_key_plus_seq_ = true;
+  }
+
   flush_policy_.reset(FlushBlockBySizePolicyFactory::NewFlushBlockPolicy(
       table_opt_.metadata_block_size, table_opt_.block_size_deviation,
       // Note: this is sub-optimal since sub_index_builder_ could later reset
@@ -129,9 +138,15 @@ void PartitionedIndexBuilder::AddIndexEntry(
     }
     sub_index_builder_->AddIndexEntry(last_key_in_current_block,
                                       first_key_in_next_block, block_handle);
-    if (sub_index_builder_->seperator_is_key_plus_seq_) {
-      // then we need to apply it to all sub-index builders
+    if (!seperator_is_key_plus_seq_ &&
+        sub_index_builder_->seperator_is_key_plus_seq_) {
+      // then we need to apply it to all sub-index builders and reset
+      // flush_policy to point to Block Builder of sub_index_builder_ that store
+      // internal keys.
       seperator_is_key_plus_seq_ = true;
+      flush_policy_.reset(FlushBlockBySizePolicyFactory::NewFlushBlockPolicy(
+          table_opt_.metadata_block_size, table_opt_.block_size_deviation,
+          sub_index_builder_->index_block_builder_));
     }
     sub_index_last_key_ = std::string(*last_key_in_current_block);
     entries_.push_back(
@@ -161,9 +176,15 @@ void PartitionedIndexBuilder::AddIndexEntry(
     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);
-    if (sub_index_builder_->seperator_is_key_plus_seq_) {
-      // then we need to apply it to all sub-index builders
+    if (!seperator_is_key_plus_seq_ &&
+        sub_index_builder_->seperator_is_key_plus_seq_) {
+      // then we need to apply it to all sub-index builders and reset
+      // flush_policy to point to Block Builder of sub_index_builder_ that store
+      // internal keys.
       seperator_is_key_plus_seq_ = true;
+      flush_policy_.reset(FlushBlockBySizePolicyFactory::NewFlushBlockPolicy(
+          table_opt_.metadata_block_size, table_opt_.block_size_deviation,
+          sub_index_builder_->index_block_builder_));
     }
   }
 }