Fix a seek issue with prefix extractor and timestamp (#7644)

Summary:
During seek, prefix compare should not include timestamp.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7644

Test Plan: added unittest

Reviewed By: riversand963

Differential Revision: D24772066

Pulled By: jay-zhuang

fbshipit-source-id: 3982655a8bf8da256a738e8497b73b3d9bdac92e

HISTORY.md

@@ -12,6 +12,7 @@
 * Reverted a behavior change silently introduced in 6.14, in which options parsing/loading functions began returning `NotFound` instead of `InvalidArgument` for option names not available in the present version.
 * Fixed MultiGet bugs it doesn't return valid data with user defined timestamp.
 * Fixed a potential bug caused by evaluating `TableBuilder::NeedCompact()` before `TableBuilder::Finish()` in compaction job. For example, the `NeedCompact()` method of `CompactOnDeletionCollector` returned by built-in `CompactOnDeletionCollectorFactory` requires `BlockBasedTable::Finish()` to return the correct result. The bug can cause a compaction-generated file not to be marked for future compaction based on deletion ratio.
+* Fixed a seek issue with prefix extractor and timestamp.
 
 ### Public API Change
 * Deprecate `BlockBasedTableOptions::pin_l0_filter_and_index_blocks_in_cache` and `BlockBasedTableOptions::pin_top_level_index_and_filter`. These options still take effect until users migrate to the replacement APIs in `BlockBasedTableOptions::metadata_cache_options`. Migration guidance can be found in the API comments on the deprecated options.

db/db_with_timestamp_basic_test.cc

@@ -244,6 +244,103 @@ TEST_F(DBBasicTestWithTimestamp, SimpleForwardIterate) {
   Close();
 }
 
+TEST_F(DBBasicTestWithTimestamp, SeekWithPrefixLessThanKey) {
+  Options options = CurrentOptions();
+  options.env = env_;
+  options.create_if_missing = true;
+  options.prefix_extractor.reset(NewFixedPrefixTransform(3));
+  BlockBasedTableOptions bbto;
+  bbto.filter_policy.reset(NewBloomFilterPolicy(10, false));
+  bbto.cache_index_and_filter_blocks = true;
+  bbto.whole_key_filtering = true;
+  options.table_factory.reset(NewBlockBasedTableFactory(bbto));
+  const size_t kTimestampSize = Timestamp(0, 0).size();
+  TestComparator test_cmp(kTimestampSize);
+  options.comparator = &test_cmp;
+  DestroyAndReopen(options);
+
+  WriteOptions write_opts;
+  std::string ts_str = Timestamp(1, 0);
+  Slice ts = ts_str;
+  write_opts.timestamp = &ts;
+
+  ASSERT_OK(db_->Put(write_opts, "foo1", "bar"));
+  Flush();
+
+  ASSERT_OK(db_->Put(write_opts, "foo2", "bar"));
+  Flush();
+
+  // Move sst file to next level
+  ASSERT_OK(db_->CompactRange(CompactRangeOptions(), nullptr, nullptr));
+
+  ASSERT_OK(db_->Put(write_opts, "foo3", "bar"));
+  Flush();
+
+  ReadOptions read_opts;
+  std::string read_ts = Timestamp(1, 0);
+  ts = read_ts;
+  read_opts.timestamp = &ts;
+  {
+    std::unique_ptr<Iterator> iter(db_->NewIterator(read_opts));
+    iter->Seek("foo");
+    ASSERT_TRUE(iter->Valid());
+    ASSERT_OK(iter->status());
+    iter->Seek("bbb");
+    ASSERT_FALSE(iter->Valid());
+    ASSERT_OK(iter->status());
+  }
+
+  Close();
+}
+
+TEST_F(DBBasicTestWithTimestamp, SeekWithPrefixLargerThanKey) {
+  Options options = CurrentOptions();
+  options.env = env_;
+  options.create_if_missing = true;
+  options.prefix_extractor.reset(NewFixedPrefixTransform(20));
+  BlockBasedTableOptions bbto;
+  bbto.filter_policy.reset(NewBloomFilterPolicy(10, false));
+  bbto.cache_index_and_filter_blocks = true;
+  bbto.whole_key_filtering = true;
+  options.table_factory.reset(NewBlockBasedTableFactory(bbto));
+  const size_t kTimestampSize = Timestamp(0, 0).size();
+  TestComparator test_cmp(kTimestampSize);
+  options.comparator = &test_cmp;
+  DestroyAndReopen(options);
+
+  WriteOptions write_opts;
+  std::string ts_str = Timestamp(1, 0);
+  Slice ts = ts_str;
+  write_opts.timestamp = &ts;
+
+  ASSERT_OK(db_->Put(write_opts, "foo1", "bar"));
+  Flush();
+
+  ASSERT_OK(db_->Put(write_opts, "foo2", "bar"));
+  Flush();
+
+  // Move sst file to next level
+  ASSERT_OK(db_->CompactRange(CompactRangeOptions(), nullptr, nullptr));
+
+  ASSERT_OK(db_->Put(write_opts, "foo3", "bar"));
+  Flush();
+
+  ReadOptions read_opts;
+  std::string read_ts = Timestamp(2, 0);
+  ts = read_ts;
+  read_opts.timestamp = &ts;
+  {
+    std::unique_ptr<Iterator> iter(db_->NewIterator(read_opts));
+    // Make sure the prefix extractor doesn't include timestamp, otherwise it
+    // may return invalid result.
+    iter->Seek("foo");
+    ASSERT_TRUE(iter->Valid());
+    ASSERT_OK(iter->status());
+  }
+
+  Close();
+}
+
 TEST_F(DBBasicTestWithTimestamp, SimpleForwardIterateLowerTsBound) {
   constexpr int kNumKeysPerFile = 128;
   constexpr uint64_t kMaxKey = 1024;

db/version_set.cc

@@ -1096,13 +1096,17 @@ void LevelIterator::Seek(const Slice& target) {
     //    next key after the prefix, or make the iterator invalid.
     // A side benefit will be that it invalidates the iterator earlier so that
     // the upper level merging iterator can merge fewer child iterators.
-    Slice target_user_key = ExtractUserKey(target);
-    Slice file_user_key = ExtractUserKey(file_iter_.key());
-    if (prefix_extractor_->InDomain(target_user_key) &&
-        (!prefix_extractor_->InDomain(file_user_key) ||
-         user_comparator_.Compare(
-             prefix_extractor_->Transform(target_user_key),
-             prefix_extractor_->Transform(file_user_key)) != 0)) {
+    size_t ts_sz = user_comparator_.timestamp_size();
+    Slice target_user_key_without_ts =
+        ExtractUserKeyAndStripTimestamp(target, ts_sz);
+    Slice file_user_key_without_ts =
+        ExtractUserKeyAndStripTimestamp(file_iter_.key(), ts_sz);
+    if (prefix_extractor_->InDomain(target_user_key_without_ts) &&
+        (!prefix_extractor_->InDomain(file_user_key_without_ts) ||
+         user_comparator_.CompareWithoutTimestamp(
+             prefix_extractor_->Transform(target_user_key_without_ts), false,
+             prefix_extractor_->Transform(file_user_key_without_ts),
+             false) != 0)) {
       SetFileIterator(nullptr);
     }
   }