Revert "Fixed the bug when both whole_key_filtering and prefix_extractor are set."

Summary:
This patch reverts commit 57605d7ef3 as it will
cause BlockBasedTableTest.NoopTransformSeek test crashes in some environment.

Test Plan: revert the patch

Reviewers: anthony, IslamAbdelRahman, rven, kradhakrishnan, sdong

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D52623

table/block_based_filter_block.cc

@@ -19,6 +19,18 @@
 namespace rocksdb {
 
 namespace {
+bool SamePrefix(const SliceTransform* prefix_extractor, const Slice& key1,
+                const Slice& key2) {
+  if (!prefix_extractor->InDomain(key1) && !prefix_extractor->InDomain(key2)) {
+    return true;
+  } else if (!prefix_extractor->InDomain(key1) ||
+             !prefix_extractor->InDomain(key2)) {
+    return false;
+  } else {
+    return (prefix_extractor->Transform(key1) ==
+            prefix_extractor->Transform(key2));
+  }
+}
 
 void AppendItem(std::string* props, const std::string& key,
                 const std::string& value) {
@@ -65,9 +77,7 @@ BlockBasedFilterBlockBuilder::BlockBasedFilterBlockBuilder(
     const BlockBasedTableOptions& table_opt)
     : policy_(table_opt.filter_policy.get()),
       prefix_extractor_(prefix_extractor),
-      whole_key_filtering_(table_opt.whole_key_filtering),
-      prev_prefix_start_(0),
-      prev_prefix_size_(0) {
+      whole_key_filtering_(table_opt.whole_key_filtering) {
   assert(policy_);
 }
 
@@ -80,12 +90,13 @@ void BlockBasedFilterBlockBuilder::StartBlock(uint64_t block_offset) {
 }
 
 void BlockBasedFilterBlockBuilder::Add(const Slice& key) {
-  if (prefix_extractor_ && prefix_extractor_->InDomain(key)) {
-    AddPrefix(key);
-  }
-
+  added_to_start_ = 0;
   if (whole_key_filtering_) {
     AddKey(key);
+    added_to_start_ = 1;
+  }
+  if (prefix_extractor_ && prefix_extractor_->InDomain(key)) {
+    AddPrefix(key);
   }
 }
 
@@ -99,16 +110,19 @@ inline void BlockBasedFilterBlockBuilder::AddKey(const Slice& key) {
 inline void BlockBasedFilterBlockBuilder::AddPrefix(const Slice& key) {
   // get slice for most recently added entry
   Slice prev;
-  if (prev_prefix_size_ > 0) {
-    prev = Slice(entries_.data() + prev_prefix_start_, prev_prefix_size_);
+  if (start_.size() > added_to_start_) {
+    size_t prev_start = start_[start_.size() - 1 - added_to_start_];
+    const char* base = entries_.data() + prev_start;
+    size_t length = entries_.size() - prev_start;
+    prev = Slice(base, length);
   }
 
-  Slice prefix = prefix_extractor_->Transform(key);
-  // insert prefix only when it's different from the previous prefix.
-  if (prev.size() == 0 || prefix != prev) {
+  // this assumes prefix(prefix(key)) == prefix(key), as the last
+  // entry in entries_ may be either a key or prefix, and we use
+  // prefix(last entry) to get the prefix of the last key.
+  if (prev.size() == 0 || !SamePrefix(prefix_extractor_, key, prev)) {
+    Slice prefix = prefix_extractor_->Transform(key);
     start_.push_back(entries_.size());
-    prev_prefix_start_ = entries_.size();
-    prev_prefix_size_ = prefix.size();
     entries_.append(prefix.data(), prefix.size());
   }
 }
@@ -154,8 +168,6 @@ void BlockBasedFilterBlockBuilder::GenerateFilter() {
   tmp_entries_.clear();
   entries_.clear();
   start_.clear();
-  prev_prefix_start_ = 0;
-  prev_prefix_size_ = 0;
 }
 
 BlockBasedFilterBlockReader::BlockBasedFilterBlockReader(

table/block_based_filter_block.h

@@ -55,12 +55,9 @@ class BlockBasedFilterBlockBuilder : public FilterBlockBuilder {
   const SliceTransform* prefix_extractor_;
   bool whole_key_filtering_;
 
-  size_t prev_prefix_start_;        // the position of the last appended prefix
-                                    // to "entries_".
-  size_t prev_prefix_size_;         // the length of the last appended prefix to
-                                    // "entries_".
   std::string entries_;             // Flattened entry contents
   std::vector<size_t> start_;       // Starting index in entries_ of each entry
+  uint32_t added_to_start_;         // To indicate if key is added
   std::string result_;              // Filter data computed so far
   std::vector<Slice> tmp_entries_;  // policy_->CreateFilter() argument
   std::vector<uint32_t> filter_offsets_;

table/table_test.cc

@@ -2281,88 +2281,6 @@ TEST_F(HarnessTest, FooterTests) {
   }
 }
 
-class PrefixTest : public testing::Test {
- public:
-  PrefixTest() : testing::Test() {}
-  ~PrefixTest() {}
-};
-
-namespace {
-// A simple PrefixExtractor that only works for test PrefixAndWholeKeyTest
-class TestPrefixExtractor : public rocksdb::SliceTransform {
- public:
-  ~TestPrefixExtractor() override{};
-  const char* Name() const override { return "TestPrefixExtractor"; }
-
-  rocksdb::Slice Transform(const rocksdb::Slice& src) const override {
-    assert(IsValid(src));
-    return rocksdb::Slice(src.data(), 3);
-  }
-
-  bool InDomain(const rocksdb::Slice& src) const override {
-    assert(IsValid(src));
-    return true;
-  }
-
-  bool InRange(const rocksdb::Slice& dst) const override { return true; }
-
-  bool IsValid(const rocksdb::Slice& src) const {
-    if (src.size() != 4) {
-      return false;
-    }
-    if (src[0] != '[') {
-      return false;
-    }
-    if (src[1] < '0' || src[1] > '9') {
-      return false;
-    }
-    if (src[2] != ']') {
-      return false;
-    }
-    if (src[3] < '0' || src[3] > '9') {
-      return false;
-    }
-    return true;
-  }
-};
-}  // namespace
-
-TEST_F(PrefixTest, PrefixAndWholeKeyTest) {
-  rocksdb::Options options;
-  options.compaction_style = rocksdb::kCompactionStyleUniversal;
-  options.num_levels = 20;
-  options.create_if_missing = true;
-  options.optimize_filters_for_hits = false;
-  options.target_file_size_base = 268435456;
-  options.prefix_extractor = std::make_shared<TestPrefixExtractor>();
-  rocksdb::BlockBasedTableOptions bbto;
-  bbto.filter_policy.reset(rocksdb::NewBloomFilterPolicy(10));
-  bbto.block_size = 262144;
-
-  bbto.whole_key_filtering = true;
-
-  const std::string kDBPath = test::TmpDir() + "/prefix_test";
-  options.table_factory.reset(NewBlockBasedTableFactory(bbto));
-  DestroyDB(kDBPath, options);
-  rocksdb::DB* db;
-  ASSERT_OK(rocksdb::DB::Open(options, kDBPath, &db));
-
-  // Create a bunch of keys with 10 filters.
-  for (int i = 0; i < 10; i++) {
-    std::string prefix = "[" + std::to_string(i) + "]";
-    for (int j = 0; j < 10; j++) {
-      std::string key = prefix + std::to_string(j);
-      db->Put(rocksdb::WriteOptions(), key, "1");
-    }
-  }
-
-  // Trigger compaction.
-  db->CompactRange(CompactRangeOptions(), nullptr, nullptr);
-  delete db;
-  // In the second round, turn whole_key_filtering off and expect
-  // rocksdb still works.
-}
-
 }  // namespace rocksdb
 
 int main(int argc, char** argv) {