Revert "Fix bad merge of D16791 and D16767"

This reverts commit 839c8ecfcd.

db/db_test.cc

@@ -4543,43 +4543,16 @@ TEST(DBTest, TransactionLogIterator) {
     {
       auto iter = OpenTransactionLogIter(0);
       ExpectRecords(3, iter);
-      assert(!iter->IsObsolete());
-      iter->Next();
-      assert(!iter->Valid());
-      assert(!iter->IsObsolete());
-      assert(iter->status().ok());
-
-      Reopen(&options);
-      env_->SleepForMicroseconds(2 * 1000 * 1000);
+    }
+    Reopen(&options);
+      env_->SleepForMicroseconds(2 * 1000 * 1000);{
       Put("key4", DummyString(1024));
       Put("key5", DummyString(1024));
       Put("key6", DummyString(1024));
-
-      iter->Next();
-      assert(!iter->Valid());
-      assert(iter->IsObsolete());
-      assert(iter->status().ok());
     }
     {
       auto iter = OpenTransactionLogIter(0);
       ExpectRecords(6, iter);
-      assert(!iter->IsObsolete());
-      iter->Next();
-      assert(!iter->Valid());
-      assert(!iter->IsObsolete());
-      assert(iter->status().ok());
-
-      Put("key7", DummyString(1024));
-      iter->Next();
-      assert(iter->Valid());
-      assert(iter->status().ok());
-
-      dbfull()->Flush(FlushOptions());
-      Put("key8", DummyString(1024));
-      iter->Next();
-      assert(!iter->Valid());
-      assert(iter->IsObsolete());
-      assert(iter->status().ok());
     }
   } while (ChangeCompactOptions());
 }

db/transaction_log_impl.cc

@@ -21,7 +21,6 @@ TransactionLogIteratorImpl::TransactionLogIteratorImpl(
       files_(std::move(files)),
       started_(false),
       isValid_(false),
-      is_obsolete_(false),
       currentFileIndex_(0),
       currentBatchSeq_(0),
       currentLastSeq_(0),
@@ -70,15 +69,14 @@ bool TransactionLogIteratorImpl::Valid() {
   return started_ && isValid_;
 }
 
-bool TransactionLogIteratorImpl::RestrictedRead(Slice* record,
-                                                std::string* scratch) {
-  bool ret = currentLogReader_->ReadRecord(record, scratch);
-
-  if (!reporter_.last_status.ok()) {
-    currentStatus_ = reporter_.last_status;
+bool TransactionLogIteratorImpl::RestrictedRead(
+    Slice* record,
+    std::string* scratch) {
+  // Don't read if no more complete entries to read from logs
+  if (currentLastSeq_ >= dbimpl_->GetLatestSequenceNumber()) {
+    return false;
   }
-
-  return ret;
+  return currentLogReader_->ReadRecord(record, scratch);
 }
 
 void TransactionLogIteratorImpl::SeekToStartSequence(
@@ -88,7 +86,6 @@ void TransactionLogIteratorImpl::SeekToStartSequence(
   Slice record;
   started_ = false;
   isValid_ = false;
-  is_obsolete_ = false;
   if (files_->size() <= startFileIndex) {
     return;
   }
@@ -97,18 +94,6 @@ void TransactionLogIteratorImpl::SeekToStartSequence(
     currentStatus_ = s;
     return;
   }
-  auto latest_seq_num = dbimpl_->GetLatestSequenceNumber();
-  if (startingSequenceNumber_ > latest_seq_num) {
-    if (strict) {
-      currentStatus_ = Status::Corruption("Gap in sequence number. Could not "
-                                          "seek to required sequence number");
-      reporter_.Info(currentStatus_.ToString().c_str());
-    } else {
-      // isValid_ is false;
-      return;
-    }
-  }
-
   while (RestrictedRead(&record, &scratch)) {
     if (record.size() < 12) {
       reporter_.Corruption(
@@ -138,11 +123,11 @@ void TransactionLogIteratorImpl::SeekToStartSequence(
   // only file. Otherwise log the error and let the iterator return next entry
   // If strict is set, we want to seek exactly till the start sequence and it
   // should have been present in the file we scanned above
-  if (strict || files_->size() == 1) {
+  if (strict) {
     currentStatus_ = Status::Corruption("Gap in sequence number. Could not "
                                         "seek to required sequence number");
     reporter_.Info(currentStatus_.ToString().c_str());
-  } else {
+  } else if (files_->size() != 1) {
     currentStatus_ = Status::Corruption("Start sequence was not found, "
                                         "skipping to the next available");
     reporter_.Info(currentStatus_.ToString().c_str());
@@ -164,30 +149,11 @@ void TransactionLogIteratorImpl::NextImpl(bool internal) {
     // Runs every time until we can seek to the start sequence
     return SeekToStartSequence();
   }
-
-  is_obsolete_ = false;
-  auto latest_seq_num = dbimpl_->GetLatestSequenceNumber();
-  if (currentLastSeq_ >= latest_seq_num) {
-    isValid_ = false;
-    return;
-  }
-
-  bool first = true;
-  while (currentFileIndex_ < files_->size()) {
-    if (!first) {
-      Status status =OpenLogReader(files_->at(currentFileIndex_).get());
-      if (!status.ok()) {
-        isValid_ = false;
-        currentStatus_ = status;
-        return;
-      }
-    }
-    first = false;
+  while(true) {
     assert(currentLogReader_);
     if (currentLogReader_->IsEOF()) {
       currentLogReader_->UnmarkEOF();
     }
-
     while (RestrictedRead(&record, &scratch)) {
       if (record.size() < 12) {
         reporter_.Corruption(
@@ -205,14 +171,26 @@ void TransactionLogIteratorImpl::NextImpl(bool internal) {
         return;
       }
     }
+
     // Open the next file
-    ++currentFileIndex_;
+    if (currentFileIndex_ < files_->size() - 1) {
+      ++currentFileIndex_;
+      Status status =OpenLogReader(files_->at(currentFileIndex_).get());
+      if (!status.ok()) {
+        isValid_ = false;
+        currentStatus_ = status;
+        return;
+      }
+    } else {
+      isValid_ = false;
+      if (currentLastSeq_ == dbimpl_->GetLatestSequenceNumber()) {
+        currentStatus_ = Status::OK();
+      } else {
+        currentStatus_ = Status::Corruption("NO MORE DATA LEFT");
+      }
+      return;
+    }
   }
-
-  // Read all the files but cannot find next record expected.
-  // TODO(sdong): support to auto fetch new log files from DB and continue.
-  isValid_ = false;
-  is_obsolete_ = true;
 }
 
 bool TransactionLogIteratorImpl::IsBatchExpected(

db/transaction_log_impl.h

@@ -19,9 +19,7 @@ namespace rocksdb {
 struct LogReporter : public log::Reader::Reporter {
   Env* env;
   Logger* info_log;
-  Status last_status;
   virtual void Corruption(size_t bytes, const Status& s) {
-    last_status = s;
     Log(info_log, "dropping %zu bytes; %s", bytes, s.ToString().c_str());
   }
   virtual void Info(const char* s) {
@@ -76,8 +74,6 @@ class TransactionLogIteratorImpl : public TransactionLogIterator {
 
   virtual bool Valid();
 
-  virtual bool IsObsolete() override { return is_obsolete_; }
-
   virtual void Next();
 
   virtual Status status();
@@ -93,7 +89,6 @@ class TransactionLogIteratorImpl : public TransactionLogIterator {
   std::unique_ptr<VectorLogPtr> files_;
   bool started_;
   bool isValid_;  // not valid when it starts of.
-  bool is_obsolete_;
   Status currentStatus_;
   size_t currentFileIndex_;
   std::unique_ptr<WriteBatch> currentBatch_;

include/rocksdb/transaction_log.h

@@ -73,12 +73,6 @@ class TransactionLogIterator {
   // Can read data from a valid iterator.
   virtual bool Valid() = 0;
 
-  // IsObsolete() returns true if new log files were created. This usually
-  // means that the user needs to close the current iterator and create a new
-  // one to get the newest updates. It should happen only when mem tables are
-  // flushed.
-  virtual bool IsObsolete() = 0;
-
   // Moves the iterator to the next WriteBatch.
   // REQUIRES: Valid() to be true.
   virtual void Next() = 0;

tools/db_repl_stress.cc

@@ -67,21 +67,8 @@ static void ReplicationThreadBody(void* arg) {
       }
     }
     fprintf(stderr, "Refreshing iterator\n");
-    for (; !iter->IsObsolete(); iter->Next()) {
-      if (!iter->Valid()) {
-        if (t->stop.Acquire_Load() == nullptr) {
-          return;
-        }
-        // need to wait for new rows.
-        continue;
-      }
-
+    for(;iter->Valid(); iter->Next(), t->no_read++, currentSeqNum++) {
       BatchResult res = iter->GetBatch();
-      if (!iter->status().ok()) {
-        fprintf(stderr, "Corruption reported when reading seq no. b/w %ld",
-                static_cast<uint64_t>(currentSeqNum));
-        exit(1);
-      }
       if (res.sequence != currentSeqNum) {
         fprintf(stderr,
                 "Missed a seq no. b/w %ld and %ld\n",
@@ -89,8 +76,6 @@ static void ReplicationThreadBody(void* arg) {
                 (long)res.sequence);
         exit(1);
       }
-      t->no_read++;
-      currentSeqNum++;
     }
   }
 }