From 7ccb8d6ef3f8f60354e79dd6b3fef776a8970842 Mon Sep 17 00:00:00 2001
From: sdong <siying.d@fb.com>
Date: Thu, 5 May 2016 17:20:22 -0700
Subject: [PATCH] BlockBasedTable::Get() not to use prefix bloom if
 read_options.total_order_seek = true

Summary: This is to provide a way for users to skip prefix bloom in point look-up.

Test Plan: Add a new unit test scenario.

Reviewers: IslamAbdelRahman

Subscribers: leveldb, andrewkr, dhruba

Differential Revision: https://reviews.facebook.net/D57747
---
 db/db_bloom_filter_test.cc        | 4 ++++
 include/rocksdb/options.h         | 3 +++
 table/block_based_table_reader.cc | 7 ++++---
 table/block_based_table_reader.h  | 3 ++-
 4 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/db/db_bloom_filter_test.cc b/db/db_bloom_filter_test.cc
index b9a86c31f..4bc9453ad 100644
--- a/db/db_bloom_filter_test.cc
+++ b/db/db_bloom_filter_test.cc
@@ -160,6 +160,10 @@ TEST_F(DBBloomFilterTest, GetFilterByPrefixBloom) {
 
   ASSERT_EQ("NOT_FOUND", Get("foobarbar"));
   ASSERT_EQ(TestGetTickerCount(options, BLOOM_FILTER_USEFUL), 2);
+
+  ro.total_order_seek = true;
+  ASSERT_TRUE(db_->Get(ro, "foobarbar", &value).IsNotFound());
+  ASSERT_EQ(TestGetTickerCount(options, BLOOM_FILTER_USEFUL), 2);
 }
 
 TEST_F(DBBloomFilterTest, WholeKeyFilterProp) {
diff --git a/include/rocksdb/options.h b/include/rocksdb/options.h
index 982bd16c6..9853d7d01 100644
--- a/include/rocksdb/options.h
+++ b/include/rocksdb/options.h
@@ -1458,6 +1458,9 @@ struct ReadOptions {
   // Enable a total order seek regardless of index format (e.g. hash index)
   // used in the table. Some table format (e.g. plain table) may not support
   // this option.
+  // If true when calling Get(), we also skip prefix bloom when reading from
+  // block based table. It provides a way to read exisiting data after
+  // changing implementation of prefix extractor.
   bool total_order_seek;
 
   // Enforce that the iterator only iterates over the same prefix as the seek.
diff --git a/table/block_based_table_reader.cc b/table/block_based_table_reader.cc
index 849813c41..82c9903fa 100644
--- a/table/block_based_table_reader.cc
+++ b/table/block_based_table_reader.cc
@@ -1332,7 +1332,8 @@ InternalIterator* BlockBasedTable::NewIterator(const ReadOptions& read_options,
       NewIndexIterator(read_options), arena);
 }
 
-bool BlockBasedTable::FullFilterKeyMayMatch(FilterBlockReader* filter,
+bool BlockBasedTable::FullFilterKeyMayMatch(const ReadOptions& read_options,
+                                            FilterBlockReader* filter,
                                             const Slice& internal_key) const {
   if (filter == nullptr || filter->IsBlockBased()) {
     return true;
@@ -1341,7 +1342,7 @@ bool BlockBasedTable::FullFilterKeyMayMatch(FilterBlockReader* filter,
   if (!filter->KeyMayMatch(user_key)) {
     return false;
   }
-  if (rep_->ioptions.prefix_extractor &&
+  if (!read_options.total_order_seek && rep_->ioptions.prefix_extractor &&
       rep_->ioptions.prefix_extractor->InDomain(user_key) &&
       !filter->PrefixMayMatch(
           rep_->ioptions.prefix_extractor->Transform(user_key))) {
@@ -1361,7 +1362,7 @@ Status BlockBasedTable::Get(const ReadOptions& read_options, const Slice& key,
 
   // First check the full filter
   // If full filter not useful, Then go into each block
-  if (!FullFilterKeyMayMatch(filter, key)) {
+  if (!FullFilterKeyMayMatch(read_options, filter, key)) {
     RecordTick(rep_->ioptions.statistics, BLOOM_FILTER_USEFUL);
   } else {
     BlockIter iiter;
diff --git a/table/block_based_table_reader.h b/table/block_based_table_reader.h
index 8f55f119b..45b303e0e 100644
--- a/table/block_based_table_reader.h
+++ b/table/block_based_table_reader.h
@@ -207,7 +207,8 @@ class BlockBasedTable : public TableReader {
       IndexReader** index_reader,
       InternalIterator* preloaded_meta_index_iter = nullptr);
 
-  bool FullFilterKeyMayMatch(FilterBlockReader* filter,
+  bool FullFilterKeyMayMatch(const ReadOptions& read_options,
+                             FilterBlockReader* filter,
                              const Slice& user_key) const;
 
   // Read the meta block from sst.