Update Flush policy in PartitionedIndexBuilder on switching from user-key to internal-key mode (#7022)

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: 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.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/7022

Test Plan:
1. make check -j64
           2. Added one unit test case

Reviewed By: ajkr

Differential Revision: D22197734

Pulled By: akankshamahajan15

fbshipit-source-id: d87e9e46bccab8e896ee6979d6b79c51f73d479e

1 files changed, 17 insertions, 4 deletions

diff --git a/table/block_based/index_builder.cc b/table/block_based/index_builder.cc
index 277bec61d..a052c65d6 100644
--- a/table/block_based/index_builder.cc
+++ b/table/block_based/index_builder.cc
@@ -112,6 +112,7 @@ void PartitionedIndexBuilder::MakeNewSubIndexBuilder() {
           ? sub_index_builder_->index_block_builder_
           : sub_index_builder_->index_block_builder_without_seq_));
   partition_cut_requested_ = false;
+  seperator_is_key_plus_seq_ = false;
 }
 
 void PartitionedIndexBuilder::RequestPartitionCut() {
@@ -129,9 +130,15 @@ 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(
@@ -161,8 +168,14 @@ 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.
+      flush_policy_.reset(FlushBlockBySizePolicyFactory::NewFlushBlockPolicy(
+          table_opt_.metadata_block_size, table_opt_.block_size_deviation,
+          sub_index_builder_->index_block_builder_));
       seperator_is_key_plus_seq_ = true;
     }
   }