Add tracing function of Seek() and SeekForPrev() to trace_replay (#4228)

Summary:
In the current trace_and replay, Get an WriteBatch are traced. This pull request track down the Seek() and SeekForPrev() to the trace file. <target_key, timestamp, column_family_id> are write to the file.

Replay of Iterator is not supported in the current implementation.

Tested with trace_analyzer.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4228

Differential Revision: D9201381

Pulled By: zhichao-cao

fbshipit-source-id: 6f9cc9cb3c20260af741bee065ec35c5c96354ab

db/db_impl.cc

@@ -1618,8 +1618,8 @@ if (read_options.tailing) {
     result = NewDBIterator(
         env_, read_options, *cfd->ioptions(), sv->mutable_cf_options,
         cfd->user_comparator(), iter, kMaxSequenceNumber,
-        sv->mutable_cf_options.max_sequential_skip_in_iterations,
-        read_callback);
+        sv->mutable_cf_options.max_sequential_skip_in_iterations, read_callback,
+        this, cfd);
 #endif
   } else {
     // Note: no need to consider the special case of
@@ -1686,9 +1686,8 @@ ArenaWrappedDBIter* DBImpl::NewIteratorImpl(const ReadOptions& read_options,
   ArenaWrappedDBIter* db_iter = NewArenaWrappedDbIterator(
       env_, read_options, *cfd->ioptions(), sv->mutable_cf_options, snapshot,
       sv->mutable_cf_options.max_sequential_skip_in_iterations,
-      sv->version_number, read_callback,
-      ((read_options.snapshot != nullptr) ? nullptr : this), cfd, allow_blob,
-      allow_refresh);
+      sv->version_number, read_callback, this, cfd, allow_blob,
+      ((read_options.snapshot != nullptr) ? false : allow_refresh));
 
   InternalIterator* internal_iter =
       NewInternalIterator(read_options, cfd, sv, db_iter->GetArena(),
@@ -1725,7 +1724,7 @@ Status DBImpl::NewIterators(
           env_, read_options, *cfd->ioptions(), sv->mutable_cf_options,
           cfd->user_comparator(), iter, kMaxSequenceNumber,
           sv->mutable_cf_options.max_sequential_skip_in_iterations,
-          read_callback));
+          read_callback, this, cfd));
     }
 #endif
   } else {
@@ -3129,5 +3128,28 @@ Status DBImpl::EndTrace() {
   return s;
 }
 
+Status DBImpl::TraceIteratorSeek(const uint32_t& cf_id, const Slice& key) {
+  Status s;
+  if (tracer_) {
+    InstrumentedMutexLock lock(&trace_mutex_);
+    if (tracer_) {
+      s = tracer_->IteratorSeek(cf_id, key);
+    }
+  }
+  return s;
+}
+
+Status DBImpl::TraceIteratorSeekForPrev(const uint32_t& cf_id, const Slice& key) {
+  Status s;
+  if (tracer_) {
+    InstrumentedMutexLock lock(&trace_mutex_);
+    if (tracer_) {
+      s = tracer_->IteratorSeekForPrev(cf_id, key);
+    }
+  }
+  return s;
+}
+
 #endif  // ROCKSDB_LITE
+
 }  // namespace rocksdb

db/db_impl.h

@@ -342,7 +342,8 @@ class DBImpl : public DB {
 
   using DB::EndTrace;
   virtual Status EndTrace() override;
-
+  Status TraceIteratorSeek(const uint32_t& cf_id, const Slice& key);
+  Status TraceIteratorSeekForPrev(const uint32_t& cf_id, const Slice& key);
 #endif  // ROCKSDB_LITE
 
   // Similar to GetSnapshot(), but also lets the db know that this snapshot

db/db_iter.cc

@@ -27,6 +27,7 @@
 #include "util/logging.h"
 #include "util/mutexlock.h"
 #include "util/string_util.h"
+#include "util/trace_replay.h"
 
 namespace rocksdb {
 
@@ -114,7 +115,8 @@ class DBIter final: public Iterator {
          const MutableCFOptions& mutable_cf_options, const Comparator* cmp,
          InternalIterator* iter, SequenceNumber s, bool arena_mode,
          uint64_t max_sequential_skip_in_iterations,
-         ReadCallback* read_callback, bool allow_blob)
+         ReadCallback* read_callback, DBImpl* db_impl, ColumnFamilyData* cfd,
+         bool allow_blob)
       : arena_mode_(arena_mode),
         env_(_env),
         logger_(cf_options.info_log),
@@ -135,6 +137,8 @@ class DBIter final: public Iterator {
         range_del_agg_(cf_options.internal_comparator, s,
                        true /* collapse_deletions */),
         read_callback_(read_callback),
+        db_impl_(db_impl),
+        cfd_(cfd),
         allow_blob_(allow_blob),
         is_blob_(false),
         start_seqnum_(read_options.iter_start_seqnum) {
@@ -344,6 +348,8 @@ class DBIter final: public Iterator {
   LocalStatistics local_stats_;
   PinnedIteratorsManager pinned_iters_mgr_;
   ReadCallback* read_callback_;
+  DBImpl* db_impl_;
+  ColumnFamilyData* cfd_;
   bool allow_blob_;
   bool is_blob_;
   // for diff snapshots we want the lower bound on the seqnum;
@@ -1267,6 +1273,12 @@ void DBIter::Seek(const Slice& target) {
   saved_key_.Clear();
   saved_key_.SetInternalKey(target, seq);
 
+#ifndef ROCKSDB_LITE
+  if (db_impl_ != nullptr && cfd_ != nullptr) {
+    db_impl_->TraceIteratorSeek(cfd_->GetID(), target);
+  }
+#endif  // ROCKSDB_LITE
+
   if (iterate_lower_bound_ != nullptr &&
       user_comparator_->Compare(saved_key_.GetUserKey(),
                                 *iterate_lower_bound_) < 0) {
@@ -1331,6 +1343,12 @@ void DBIter::SeekForPrev(const Slice& target) {
     range_del_agg_.InvalidateRangeDelMapPositions();
   }
 
+#ifndef ROCKSDB_LITE
+  if (db_impl_ != nullptr && cfd_ != nullptr) {
+    db_impl_->TraceIteratorSeekForPrev(cfd_->GetID(), target);
+  }
+#endif  // ROCKSDB_LITE
+
   RecordTick(statistics_, NUMBER_DB_SEEK);
   if (iter_->Valid()) {
     if (prefix_extractor_ && prefix_same_as_start_) {
@@ -1453,11 +1471,12 @@ Iterator* NewDBIterator(Env* env, const ReadOptions& read_options,
                         InternalIterator* internal_iter,
                         const SequenceNumber& sequence,
                         uint64_t max_sequential_skip_in_iterations,
-                        ReadCallback* read_callback, bool allow_blob) {
-  DBIter* db_iter =
-      new DBIter(env, read_options, cf_options, mutable_cf_options,
-                 user_key_comparator, internal_iter, sequence, false,
-                 max_sequential_skip_in_iterations, read_callback, allow_blob);
+                        ReadCallback* read_callback, DBImpl* db_impl,
+                        ColumnFamilyData* cfd, bool allow_blob) {
+  DBIter* db_iter = new DBIter(
+      env, read_options, cf_options, mutable_cf_options, user_key_comparator,
+      internal_iter, sequence, false, max_sequential_skip_in_iterations,
+      read_callback, db_impl, cfd, allow_blob);
   return db_iter;
 }
 
@@ -1504,13 +1523,14 @@ void ArenaWrappedDBIter::Init(Env* env, const ReadOptions& read_options,
                               const SequenceNumber& sequence,
                               uint64_t max_sequential_skip_in_iteration,
                               uint64_t version_number,
-                              ReadCallback* read_callback, bool allow_blob,
+                              ReadCallback* read_callback, DBImpl* db_impl,
+                              ColumnFamilyData* cfd, bool allow_blob,
                               bool allow_refresh) {
   auto mem = arena_.AllocateAligned(sizeof(DBIter));
-  db_iter_ = new (mem)
-      DBIter(env, read_options, cf_options, mutable_cf_options,
-             cf_options.user_comparator, nullptr, sequence, true,
-             max_sequential_skip_in_iteration, read_callback, allow_blob);
+  db_iter_ = new (mem) DBIter(env, read_options, cf_options, mutable_cf_options,
+                              cf_options.user_comparator, nullptr, sequence,
+                              true, max_sequential_skip_in_iteration,
+                              read_callback, db_impl, cfd, allow_blob);
   sv_number_ = version_number;
   allow_refresh_ = allow_refresh;
 }
@@ -1534,7 +1554,8 @@ Status ArenaWrappedDBIter::Refresh() {
     SuperVersion* sv = cfd_->GetReferencedSuperVersion(db_impl_->mutex());
     Init(env, read_options_, *(cfd_->ioptions()), sv->mutable_cf_options,
          latest_seq, sv->mutable_cf_options.max_sequential_skip_in_iterations,
-         cur_sv_number, read_callback_, allow_blob_, allow_refresh_);
+         cur_sv_number, read_callback_, db_impl_, cfd_, allow_blob_,
+         allow_refresh_);
 
     InternalIterator* internal_iter = db_impl_->NewInternalIterator(
         read_options_, cfd_, sv, &arena_, db_iter_->GetRangeDelAggregator());
@@ -1556,7 +1577,7 @@ ArenaWrappedDBIter* NewArenaWrappedDbIterator(
   ArenaWrappedDBIter* iter = new ArenaWrappedDBIter();
   iter->Init(env, read_options, cf_options, mutable_cf_options, sequence,
              max_sequential_skip_in_iterations, version_number, read_callback,
-             allow_blob, allow_refresh);
+             db_impl, cfd, allow_blob, allow_refresh);
   if (db_impl != nullptr && cfd != nullptr && allow_refresh) {
     iter->StoreRefreshInfo(read_options, db_impl, cfd, read_callback,
                            allow_blob);

db/db_iter.h

@@ -27,15 +27,14 @@ class DBIter;
 // Return a new iterator that converts internal keys (yielded by
 // "*internal_iter") that were live at the specified "sequence" number
 // into appropriate user keys.
-extern Iterator* NewDBIterator(Env* env, const ReadOptions& read_options,
+extern Iterator* NewDBIterator(
+    Env* env, const ReadOptions& read_options,
     const ImmutableCFOptions& cf_options,
     const MutableCFOptions& mutable_cf_options,
-                               const Comparator* user_key_comparator,
-                               InternalIterator* internal_iter,
-                               const SequenceNumber& sequence,
-                               uint64_t max_sequential_skip_in_iterations,
-                               ReadCallback* read_callback,
-                               bool allow_blob = false);
+    const Comparator* user_key_comparator, InternalIterator* internal_iter,
+    const SequenceNumber& sequence, uint64_t max_sequential_skip_in_iterations,
+    ReadCallback* read_callback, DBImpl* db_impl = nullptr,
+    ColumnFamilyData* cfd = nullptr, bool allow_blob = false);
 
 // A wrapper iterator which wraps DB Iterator and the arena, with which the DB
 // iterator is supposed be allocated. This class is used as an entry point of
@@ -74,7 +73,8 @@ class ArenaWrappedDBIter : public Iterator {
             const MutableCFOptions& mutable_cf_options,
             const SequenceNumber& sequence,
             uint64_t max_sequential_skip_in_iterations, uint64_t version_number,
-            ReadCallback* read_callback, bool allow_blob, bool allow_refresh);
+            ReadCallback* read_callback, DBImpl* db_impl, ColumnFamilyData* cfd,
+            bool allow_blob, bool allow_refresh);
 
   void StoreRefreshInfo(const ReadOptions& read_options, DBImpl* db_impl,
                         ColumnFamilyData* cfd, ReadCallback* read_callback,

db/db_iterator_test.cc

@@ -2093,6 +2093,34 @@ TEST_P(DBIteratorTest, Refresh) {
   iter.reset();
 }
 
+TEST_P(DBIteratorTest, RefreshWithSnapshot) {
+  ASSERT_OK(Put("x", "y"));
+  const Snapshot* snapshot = db_->GetSnapshot();
+  ReadOptions options;
+  options.snapshot = snapshot;
+  Iterator* iter = NewIterator(options);
+
+  iter->Seek(Slice("a"));
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ(iter->key().compare(Slice("x")), 0);
+  iter->Next();
+  ASSERT_FALSE(iter->Valid());
+
+  ASSERT_OK(Put("c", "d"));
+
+  iter->Seek(Slice("a"));
+  ASSERT_TRUE(iter->Valid());
+  ASSERT_EQ(iter->key().compare(Slice("x")), 0);
+  iter->Next();
+  ASSERT_FALSE(iter->Valid());
+
+  Status s;
+  s = iter->Refresh();
+  ASSERT_TRUE(s.IsNotSupported());
+  db_->ReleaseSnapshot(snapshot);
+  delete iter;
+}
+
 TEST_P(DBIteratorTest, CreationFailure) {
   SyncPoint::GetInstance()->SetCallBack(
       "DBImpl::NewInternalIterator:StatusCallback", [](void* arg) {

db/db_test2.cc

@@ -2509,6 +2509,7 @@ TEST_F(DBTest2, TraceAndReplay) {
   EnvOptions env_opts;
   CreateAndReopenWithCF({"pikachu"}, options);
   Random rnd(301);
+  Iterator* single_iter = nullptr;
 
   std::string trace_filename = dbname_ + "/rocksdb.trace";
   std::unique_ptr<TraceWriter> trace_writer;
@@ -2529,6 +2530,11 @@ TEST_F(DBTest2, TraceAndReplay) {
   ASSERT_OK(batch.DeleteRange("j", "k"));
   ASSERT_OK(db_->Write(wo, &batch));
 
+  single_iter = db_->NewIterator(ro);
+  single_iter->Seek("f");
+  single_iter->SeekForPrev("g");
+  delete single_iter;
+
   ASSERT_EQ("1", Get(0, "a"));
   ASSERT_EQ("12", Get(0, "g"));
 

util/trace_replay.cc

@@ -52,6 +52,22 @@ Status Tracer::Get(ColumnFamilyHandle* column_family, const Slice& key) {
   return WriteTrace(trace);
 }
 
+Status Tracer::IteratorSeek(const uint32_t& cf_id, const Slice& key) {
+  Trace trace;
+  trace.ts = env_->NowMicros();
+  trace.type = kTraceIteratorSeek;
+  EncodeCFAndKey(&trace.payload, cf_id, key);
+  return WriteTrace(trace);
+}
+
+Status Tracer::IteratorSeekForPrev(const uint32_t& cf_id, const Slice& key) {
+  Trace trace;
+  trace.ts = env_->NowMicros();
+  trace.type = kTraceIteratorSeekForPrev;
+  EncodeCFAndKey(&trace.payload, cf_id, key);
+  return WriteTrace(trace);
+}
+
 Status Tracer::WriteHeader() {
   std::ostringstream s;
   s << kTraceMagic << "\t"
@@ -112,6 +128,7 @@ Status Replayer::Replay() {
   ReadOptions roptions;
   Trace trace;
   uint64_t ops = 0;
+  Iterator* single_iter = nullptr;
   while (s.ok()) {
     trace.reset();
     s = ReadTrace(&trace);
@@ -140,6 +157,39 @@ Status Replayer::Replay() {
         db_->Get(roptions, cf_map_[cf_id], key, &value);
       }
       ops++;
+    } else if (trace.type == kTraceIteratorSeek) {
+      uint32_t cf_id = 0;
+      Slice key;
+      DecodeCFAndKey(trace.payload, &cf_id, &key);
+      if (cf_id > 0 && cf_map_.find(cf_id) == cf_map_.end()) {
+        return Status::Corruption("Invalid Column Family ID.");
+      }
+
+      if (cf_id == 0) {
+        single_iter = db_->NewIterator(roptions);
+      } else {
+        single_iter = db_->NewIterator(roptions, cf_map_[cf_id]);
+      }
+      single_iter->Seek(key);
+      ops++;
+      delete single_iter;
+    } else if (trace.type == kTraceIteratorSeekForPrev) {
+      // Currently, only support to call the Seek()
+      uint32_t cf_id = 0;
+      Slice key;
+      DecodeCFAndKey(trace.payload, &cf_id, &key);
+      if (cf_id > 0 && cf_map_.find(cf_id) == cf_map_.end()) {
+        return Status::Corruption("Invalid Column Family ID.");
+      }
+
+      if (cf_id == 0) {
+        single_iter = db_->NewIterator(roptions);
+      } else {
+        single_iter = db_->NewIterator(roptions, cf_map_[cf_id]);
+      }
+      single_iter->SeekForPrev(key);
+      ops++;
+      delete single_iter;
     } else if (trace.type == kTraceEnd) {
       // Do nothing for now.
       // TODO: Add some validations later.

util/trace_replay.h

@@ -15,6 +15,7 @@
 namespace rocksdb {
 
 class ColumnFamilyHandle;
+class ColumnFamilyData;
 class DB;
 class DBImpl;
 class Slice;
@@ -32,6 +33,8 @@ enum TraceType : char {
   kTraceEnd = 2,
   kTraceWrite = 3,
   kTraceGet = 4,
+  kTraceIteratorSeek = 5,
+  kTraceIteratorSeekForPrev = 6,
   kTraceMax,
 };
 
@@ -57,6 +60,8 @@ class Tracer {
 
   Status Write(WriteBatch* write_batch);
   Status Get(ColumnFamilyHandle* cfname, const Slice& key);
+  Status IteratorSeek(const uint32_t& cf_id, const Slice& key);
+  Status IteratorSeekForPrev(const uint32_t& cf_id, const Slice& key);
 
   Status Close();