Improve stress test for MultiOpsTxnsStressTest (#9829)

Summary: Adds more coverage to `MultiOpsTxnsStressTest` with a focus on write-prepared transactions. 1. Add a hack to manually evict commit cache entries. We currently cannot assign small values to `wp_commit_cache_bits` because it requires a prepared transaction to commit within a certain range of sequence numbers, otherwise it will throw. 2. Add coverage for commit-time-write-batch. If write policy is write-prepared, we need to set `use_only_the_last_commit_time_batch_for_recovery` to true. 3. After each flush/compaction, verify data consistency. This is possible since data size can be small: default numbers of primary/secondary keys are just 1000. Pull Request resolved: https://github.com/facebook/rocksdb/pull/9829 Test Plan: ``` TEST_TMPDIR=/dev/shm/rocksdb_crashtest_blackbox/ make blackbox_crash_test_with_multiops_wp_txn ``` Reviewed By: pdillinger Differential Revision: D35806678 Pulled By: riversand963 fbshipit-source-id: d7fde7a29fda0fb481a61f553e0ca0c47da93616
3 years ago · 94e245a14d
parent d9d456de49
commit 94e245a14d
7 changed files with 371 additions and 107 deletions
--- a/db_stress_tool/db_stress_test_base.cc
+++ b/db_stress_tool/db_stress_test_base.cc
@ -2613,6 +2613,7 @@ void StressTest::Open() {
    options_.listeners.emplace_back(new DbStressListener(
        FLAGS_db, options_.db_paths, cf_descriptors, db_stress_listener_env));
 #endif  // !ROCKSDB_LITE
+    RegisterAdditionalListeners();
    options_.create_missing_column_families = true;
    if (!FLAGS_use_txn) {
 #ifndef NDEBUG
@ -2751,6 +2752,7 @@ void StressTest::Open() {
          static_cast<size_t>(FLAGS_wp_snapshot_cache_bits);
      txn_db_options.wp_commit_cache_bits =
          static_cast<size_t>(FLAGS_wp_commit_cache_bits);
+      PrepareTxnDbOptions(txn_db_options);
      s = TransactionDB::Open(options_, txn_db_options, FLAGS_db,
                              cf_descriptors, &column_families_, &txn_db_);
      if (!s.ok()) {
--- a/db_stress_tool/db_stress_test_base.h
+++ b/db_stress_tool/db_stress_test_base.h
@ -16,6 +16,7 @@ namespace ROCKSDB_NAMESPACE {
 class SystemClock;
 class Transaction;
 class TransactionDB;
+struct TransactionDBOptions;

 class StressTest {
 public:
@ -224,6 +225,12 @@ class StressTest {

  void CheckAndSetOptionsForUserTimestamp();

+  virtual void RegisterAdditionalListeners() {}
+
+#ifndef ROCKSDB_LITE
+  virtual void PrepareTxnDbOptions(TransactionDBOptions& /*txn_db_opts*/) {}
+#endif
+
  std::shared_ptr<Cache> cache_;
  std::shared_ptr<Cache> compressed_cache_;
  std::shared_ptr<const FilterPolicy> filter_policy_;
--- a/db_stress_tool/multi_ops_txns_stress.cc
+++ b/db_stress_tool/multi_ops_txns_stress.cc
@ -15,6 +15,7 @@
 #ifndef NDEBUG
 #include "utilities/fault_injection_fs.h"
 #endif  // NDEBUG
+#include "utilities/transactions/write_prepared_txn_db.h"

 namespace ROCKSDB_NAMESPACE {

@ -31,6 +32,21 @@ DEFINE_int32(delay_snapshot_read_one_in, 0,
             "With a chance of 1/N, inject a random delay between taking "
             "snapshot and read.");

+DEFINE_int32(rollback_one_in, 0,
+             "If non-zero, rollback non-read-only transactions with a "
+             "probability of 1/N.");
+
+DEFINE_int32(clear_wp_commit_cache_one_in, 0,
+             "If non-zero, evict all commit entries from commit cache with a "
+             "probability of 1/N. This options applies to write-prepared and "
+             "write-unprepared transactions.");
+
+extern "C" bool rocksdb_write_prepared_TEST_ShouldClearCommitCache(void) {
+  static Random rand(static_cast<uint32_t>(db_stress_env->NowMicros()));
+  return FLAGS_clear_wp_commit_cache_one_in > 0 &&
+         rand.OneIn(FLAGS_clear_wp_commit_cache_one_in);
+}
+
 // MultiOpsTxnsStressTest can either operate on a database with pre-populated
 // data (possibly from previous ones), or create a new db and preload it with
 // data specified via `-lb_a`, `-ub_a`, `-lb_c`, `-ub_c`, etc. Among these, we
@ -75,8 +91,9 @@ void MultiOpsTxnsStressTest::KeyGenerator::FinishInit() {
        "Cannot allocate key in [%u, %u)\nStart with a new DB or try change "
        "the number of threads for testing via -threads=<#threads>\n",
        static_cast<unsigned int>(low_), static_cast<unsigned int>(high_));
+    fflush(stdout);
    fflush(stderr);
-    std::terminate();
+    assert(false);
  }
  initialized_ = true;
 }
@ -131,33 +148,43 @@ void MultiOpsTxnsStressTest::KeyGenerator::UndoAllocation(uint32_t new_val) {
 }

 std::string MultiOpsTxnsStressTest::Record::EncodePrimaryKey(uint32_t a) {
-  char buf[8];
-  EncodeFixed32(buf, kPrimaryIndexId);
-  std::reverse(buf, buf + 4);
-  EncodeFixed32(buf + 4, a);
-  std::reverse(buf + 4, buf + 8);
-  return std::string(buf, sizeof(buf));
+  std::string ret;
+  PutFixed32(&ret, kPrimaryIndexId);
+  PutFixed32(&ret, a);
+
+  char* const buf = &ret[0];
+  std::reverse(buf, buf + sizeof(kPrimaryIndexId));
+  std::reverse(buf + sizeof(kPrimaryIndexId),
+               buf + sizeof(kPrimaryIndexId) + sizeof(a));
+  return ret;
 }

 std::string MultiOpsTxnsStressTest::Record::EncodeSecondaryKey(uint32_t c) {
-  char buf[8];
-  EncodeFixed32(buf, kSecondaryIndexId);
-  std::reverse(buf, buf + 4);
-  EncodeFixed32(buf + 4, c);
-  std::reverse(buf + 4, buf + 8);
-  return std::string(buf, sizeof(buf));
+  std::string ret;
+  PutFixed32(&ret, kSecondaryIndexId);
+  PutFixed32(&ret, c);
+
+  char* const buf = &ret[0];
+  std::reverse(buf, buf + sizeof(kSecondaryIndexId));
+  std::reverse(buf + sizeof(kSecondaryIndexId),
+               buf + sizeof(kSecondaryIndexId) + sizeof(c));
+  return ret;
 }

 std::string MultiOpsTxnsStressTest::Record::EncodeSecondaryKey(uint32_t c,
                                                               uint32_t a) {
-  char buf[12];
-  EncodeFixed32(buf, kSecondaryIndexId);
-  std::reverse(buf, buf + 4);
-  EncodeFixed32(buf + 4, c);
-  EncodeFixed32(buf + 8, a);
-  std::reverse(buf + 4, buf + 8);
-  std::reverse(buf + 8, buf + 12);
-  return std::string(buf, sizeof(buf));
+  std::string ret;
+  PutFixed32(&ret, kSecondaryIndexId);
+  PutFixed32(&ret, c);
+  PutFixed32(&ret, a);
+
+  char* const buf = &ret[0];
+  std::reverse(buf, buf + sizeof(kSecondaryIndexId));
+  std::reverse(buf + sizeof(kSecondaryIndexId),
+               buf + sizeof(kSecondaryIndexId) + sizeof(c));
+  std::reverse(buf + sizeof(kSecondaryIndexId) + sizeof(c),
+               buf + sizeof(kSecondaryIndexId) + sizeof(c) + sizeof(a));
+  return ret;
 }

 std::tuple<Status, uint32_t, uint32_t>
@ -201,40 +228,26 @@ std::string MultiOpsTxnsStressTest::Record::EncodePrimaryKey() const {
 }

 std::string MultiOpsTxnsStressTest::Record::EncodePrimaryIndexValue() const {
-  char buf[8];
-  EncodeFixed32(buf, b_);
-  EncodeFixed32(buf + 4, c_);
-  return std::string(buf, sizeof(buf));
+  std::string ret;
+  PutFixed32(&ret, b_);
+  PutFixed32(&ret, c_);
+  return ret;
 }

 std::pair<std::string, std::string>
 MultiOpsTxnsStressTest::Record::EncodeSecondaryIndexEntry() const {
-  std::string secondary_index_key;
-  char buf[12];
-  EncodeFixed32(buf, kSecondaryIndexId);
-  std::reverse(buf, buf + 4);
-  EncodeFixed32(buf + 4, c_);
-  EncodeFixed32(buf + 8, a_);
-  std::reverse(buf + 4, buf + 8);
-  std::reverse(buf + 8, buf + 12);
-  secondary_index_key.assign(buf, sizeof(buf));
+  std::string secondary_index_key = EncodeSecondaryKey(c_, a_);

  // Secondary index value is always 4-byte crc32 of the secondary key
  std::string secondary_index_value;
-  uint32_t crc = crc32c::Value(buf, sizeof(buf));
+  uint32_t crc =
+      crc32c::Value(secondary_index_key.data(), secondary_index_key.size());
  PutFixed32(&secondary_index_value, crc);
-  return std::make_pair(secondary_index_key, secondary_index_value);
+  return std::make_pair(std::move(secondary_index_key), secondary_index_value);
 }

 std::string MultiOpsTxnsStressTest::Record::EncodeSecondaryKey() const {
-  char buf[12];
-  EncodeFixed32(buf, kSecondaryIndexId);
-  std::reverse(buf, buf + 4);
-  EncodeFixed32(buf + 4, c_);
-  EncodeFixed32(buf + 8, a_);
-  std::reverse(buf + 4, buf + 8);
-  std::reverse(buf + 8, buf + 12);
-  return std::string(buf, sizeof(buf));
+  return EncodeSecondaryKey(c_, a_);
 }

 Status MultiOpsTxnsStressTest::Record::DecodePrimaryIndexEntry(
@ -244,27 +257,22 @@ Status MultiOpsTxnsStressTest::Record::DecodePrimaryIndexEntry(
    return Status::Corruption("Primary index key length is not 8");
  }

-  const char* const index_id_buf = primary_index_key.data();
-  uint32_t index_id =
-      static_cast<uint32_t>(static_cast<unsigned char>(index_id_buf[0])) << 24;
-  index_id += static_cast<uint32_t>(static_cast<unsigned char>(index_id_buf[1]))
-              << 16;
-  index_id += static_cast<uint32_t>(static_cast<unsigned char>(index_id_buf[2]))
-              << 8;
-  index_id +=
-      static_cast<uint32_t>(static_cast<unsigned char>(index_id_buf[3]));
-  primary_index_key.remove_prefix(sizeof(uint32_t));
+  uint32_t index_id = 0;
+
+  [[maybe_unused]] bool res = GetFixed32(&primary_index_key, &index_id);
+  assert(res);
+  index_id = EndianSwapValue(index_id);
+
  if (index_id != kPrimaryIndexId) {
    std::ostringstream oss;
    oss << "Unexpected primary index id: " << index_id;
    return Status::Corruption(oss.str());
  }

-  const char* const buf = primary_index_key.data();
-  a_ = static_cast<uint32_t>(static_cast<unsigned char>(buf[0])) << 24;
-  a_ += static_cast<uint32_t>(static_cast<unsigned char>(buf[1])) << 16;
-  a_ += static_cast<uint32_t>(static_cast<unsigned char>(buf[2])) << 8;
-  a_ += static_cast<uint32_t>(static_cast<unsigned char>(buf[3]));
+  res = GetFixed32(&primary_index_key, &a_);
+  assert(res);
+  a_ = EndianSwapValue(a_);
+  assert(primary_index_key.empty());

  if (primary_index_value.size() != 8) {
    return Status::Corruption("Primary index value length is not 8");
@ -282,33 +290,28 @@ Status MultiOpsTxnsStressTest::Record::DecodeSecondaryIndexEntry(
  uint32_t crc =
      crc32c::Value(secondary_index_key.data(), secondary_index_key.size());

-  const char* const index_id_buf = secondary_index_key.data();
-  uint32_t index_id =
-      static_cast<uint32_t>(static_cast<unsigned char>(index_id_buf[0])) << 24;
-  index_id += static_cast<uint32_t>(static_cast<unsigned char>(index_id_buf[1]))
-              << 16;
-  index_id += static_cast<uint32_t>(static_cast<unsigned char>(index_id_buf[2]))
-              << 8;
-  index_id +=
-      static_cast<uint32_t>(static_cast<unsigned char>(index_id_buf[3]));
-  secondary_index_key.remove_prefix(sizeof(uint32_t));
+  uint32_t index_id = 0;
+
+  [[maybe_unused]] bool res = GetFixed32(&secondary_index_key, &index_id);
+  assert(res);
+  index_id = EndianSwapValue(index_id);
+
  if (index_id != kSecondaryIndexId) {
    std::ostringstream oss;
    oss << "Unexpected secondary index id: " << index_id;
    return Status::Corruption(oss.str());
  }

-  const char* const buf = secondary_index_key.data();
  assert(secondary_index_key.size() == 8);
-  c_ = static_cast<uint32_t>(static_cast<unsigned char>(buf[0])) << 24;
-  c_ += static_cast<uint32_t>(static_cast<unsigned char>(buf[1])) << 16;
-  c_ += static_cast<uint32_t>(static_cast<unsigned char>(buf[2])) << 8;
-  c_ += static_cast<uint32_t>(static_cast<unsigned char>(buf[3]));
+  res = GetFixed32(&secondary_index_key, &c_);
+  assert(res);
+  c_ = EndianSwapValue(c_);

-  a_ = static_cast<uint32_t>(static_cast<unsigned char>(buf[4])) << 24;
-  a_ += static_cast<uint32_t>(static_cast<unsigned char>(buf[5])) << 16;
-  a_ += static_cast<uint32_t>(static_cast<unsigned char>(buf[6])) << 8;
-  a_ += static_cast<uint32_t>(static_cast<unsigned char>(buf[7]));
+  assert(secondary_index_key.size() == 4);
+  res = GetFixed32(&secondary_index_key, &a_);
+  assert(res);
+  a_ = EndianSwapValue(a_);
+  assert(secondary_index_key.empty());

  if (secondary_index_value.size() != 4) {
    return Status::Corruption("Secondary index value length is not 4");
@ -520,9 +523,35 @@ Status MultiOpsTxnsStressTest::TestCustomOperations(
    // Should never reach here.
    assert(false);
  }
+
  return s;
 }

+void MultiOpsTxnsStressTest::RegisterAdditionalListeners() {
+  options_.listeners.emplace_back(new MultiOpsTxnsStressListener(this));
+}
+
+#ifndef ROCKSDB_LITE
+void MultiOpsTxnsStressTest::PrepareTxnDbOptions(
+    TransactionDBOptions& txn_db_opts) {
+  // MultiOpsTxnStressTest uses SingleDelete to delete secondary keys, thus we
+  // register this callback to let TxnDb know that when rolling back
+  // a transaction, use only SingleDelete to cancel prior Put from the same
+  // transaction if applicable.
+  txn_db_opts.rollback_deletion_type_callback =
+      [](TransactionDB* /*db*/, ColumnFamilyHandle* /*column_family*/,
+         const Slice& key) {
+        Slice ks = key;
+        uint32_t index_id = 0;
+        [[maybe_unused]] bool res = GetFixed32(&ks, &index_id);
+        assert(res);
+        index_id = EndianSwapValue(index_id);
+        assert(index_id <= Record::kSecondaryIndexId);
+        return index_id == Record::kSecondaryIndexId;
+      };
+}
+#endif  // !ROCKSDB_LITE
+
 Status MultiOpsTxnsStressTest::PrimaryKeyUpdateTxn(ThreadState* thread,
                                                   uint32_t old_a,
                                                   uint32_t old_a_pos,
@ -561,8 +590,10 @@ Status MultiOpsTxnsStressTest::PrimaryKeyUpdateTxn(ThreadState* thread,
    }
    if (s.IsNotFound()) {
      thread->stats.AddGets(/*ngets=*/1, /*nfounds=*/0);
-    } else if (s.IsBusy()) {
+    } else if (s.IsBusy() || s.IsIncomplete()) {
      // ignore.
+      // Incomplete also means rollback by application. See the transaction
+      // implementations.
    } else {
      thread->stats.AddErrors(1);
    }
@ -631,6 +662,16 @@ Status MultiOpsTxnsStressTest::PrimaryKeyUpdateTxn(ThreadState* thread,
    return s;
  }

+  if (FLAGS_rollback_one_in > 0 && thread->rand.OneIn(FLAGS_rollback_one_in)) {
+    s = Status::Incomplete();
+    return s;
+  }
+
+  s = WriteToCommitTimeWriteBatch(*txn);
+  if (!s.ok()) {
+    return s;
+  }
+
  s = txn->Commit();

  auto& key_gen = key_gen_for_a_.at(thread->tid);
@ -677,11 +718,12 @@ Status MultiOpsTxnsStressTest::SecondaryKeyUpdateTxn(ThreadState* thread,
          Record::kPrimaryIndexEntrySize + Record::kSecondaryIndexEntrySize);
      return;
    } else if (s.IsBusy() || s.IsTimedOut() || s.IsTryAgain() ||
-               s.IsMergeInProgress()) {
+               s.IsMergeInProgress() || s.IsIncomplete()) {
      // ww-conflict detected, or
      // lock cannot be acquired, or
      // memtable history is not large enough for conflict checking, or
-      // Merge operation cannot be resolved.
+      // Merge operation cannot be resolved, or
+      // application rollback.
      // TODO (yanqin) add stats for other cases?
    } else if (s.IsNotFound()) {
      // ignore.
@ -727,8 +769,9 @@ Status MultiOpsTxnsStressTest::SecondaryKeyUpdateTxn(ThreadState* thread,
    Record record;
    s = record.DecodeSecondaryIndexEntry(it->key(), it->value());
    if (!s.ok()) {
-      fprintf(stderr, "Cannot decode secondary key: %s\n",
-              s.ToString().c_str());
+      fprintf(stderr, "Cannot decode secondary key (%s => %s): %s\n",
+              it->key().ToString(true).c_str(),
+              it->value().ToString(true).c_str(), s.ToString().c_str());
      assert(false);
      break;
    }
@ -749,21 +792,31 @@ Status MultiOpsTxnsStressTest::SecondaryKeyUpdateTxn(ThreadState* thread,
    } else if (s.IsNotFound()) {
      // We can also fail verification here.
      std::ostringstream oss;
-      oss << "pk should exist: " << Slice(pk).ToString(true);
+      auto* dbimpl = static_cast_with_check<DBImpl>(db_->GetRootDB());
+      assert(dbimpl);
+      oss << "snap " << read_opts.snapshot->GetSequenceNumber()
+          << " (published " << dbimpl->GetLastPublishedSequence()
+          << "), pk should exist: " << Slice(pk).ToString(true);
      fprintf(stderr, "%s\n", oss.str().c_str());
      assert(false);
      break;
    }
    if (!s.ok()) {
-      fprintf(stderr, "%s\n", s.ToString().c_str());
+      std::ostringstream oss;
+      auto* dbimpl = static_cast_with_check<DBImpl>(db_->GetRootDB());
+      assert(dbimpl);
+      oss << "snap " << read_opts.snapshot->GetSequenceNumber()
+          << " (published " << dbimpl->GetLastPublishedSequence() << "), "
+          << s.ToString();
+      fprintf(stderr, "%s\n", oss.str().c_str());
      assert(false);
      break;
    }
    auto result = Record::DecodePrimaryIndexValue(value);
    s = std::get<0>(result);
    if (!s.ok()) {
-      fprintf(stderr, "Cannot decode primary index value: %s\n",
-              s.ToString().c_str());
+      fprintf(stderr, "Cannot decode primary index value %s: %s\n",
+              Slice(value).ToString(true).c_str(), s.ToString().c_str());
      assert(false);
      break;
    }
@ -771,8 +824,12 @@ Status MultiOpsTxnsStressTest::SecondaryKeyUpdateTxn(ThreadState* thread,
    uint32_t c = std::get<2>(result);
    if (c != old_c) {
      std::ostringstream oss;
-      oss << "c in primary index does not match secondary index: " << c
-          << " != " << old_c;
+      auto* dbimpl = static_cast_with_check<DBImpl>(db_->GetRootDB());
+      assert(dbimpl);
+      oss << "snap " << read_opts.snapshot->GetSequenceNumber()
+          << " (published " << dbimpl->GetLastPublishedSequence()
+          << "), pk/sk mismatch. pk: (a=" << record.a_value() << ", "
+          << "c=" << c << "), sk: (c=" << old_c << ")";
      s = Status::Corruption();
      fprintf(stderr, "%s\n", oss.str().c_str());
      assert(false);
@ -811,6 +868,16 @@ Status MultiOpsTxnsStressTest::SecondaryKeyUpdateTxn(ThreadState* thread,
    return s;
  }

+  if (FLAGS_rollback_one_in > 0 && thread->rand.OneIn(FLAGS_rollback_one_in)) {
+    s = Status::Incomplete();
+    return s;
+  }
+
+  s = WriteToCommitTimeWriteBatch(*txn);
+  if (!s.ok()) {
+    return s;
+  }
+
  s = txn->Commit();

  if (s.ok()) {
@ -856,7 +923,7 @@ Status MultiOpsTxnsStressTest::UpdatePrimaryIndexValueTxn(ThreadState* thread,
    } else if (s.IsInvalidArgument()) {
      // ignored.
    } else if (s.IsBusy() || s.IsTimedOut() || s.IsTryAgain() ||
-               s.IsMergeInProgress()) {
+               s.IsMergeInProgress() || s.IsIncomplete()) {
      // ignored.
    } else {
      thread->stats.AddErrors(1);
@ -874,8 +941,8 @@ Status MultiOpsTxnsStressTest::UpdatePrimaryIndexValueTxn(ThreadState* thread,
  auto result = Record::DecodePrimaryIndexValue(value);
  if (!std::get<0>(result).ok()) {
    s = std::get<0>(result);
-    fprintf(stderr, "Cannot decode primary index value: %s\n",
-            s.ToString().c_str());
+    fprintf(stderr, "Cannot decode primary index value %s: %s\n",
+            Slice(value).ToString(true).c_str(), s.ToString().c_str());
    assert(false);
    return s;
  }
@ -892,6 +959,17 @@ Status MultiOpsTxnsStressTest::UpdatePrimaryIndexValueTxn(ThreadState* thread,
  if (!s.ok()) {
    return s;
  }
+
+  if (FLAGS_rollback_one_in > 0 && thread->rand.OneIn(FLAGS_rollback_one_in)) {
+    s = Status::Incomplete();
+    return s;
+  }
+
+  s = WriteToCommitTimeWriteBatch(*txn);
+  if (!s.ok()) {
+    return s;
+  }
+
  s = txn->Commit();
  if (s.ok()) {
    delete txn;
@ -1050,12 +1128,15 @@ void MultiOpsTxnsStressTest::VerifyDb(ThreadState* thread) const {
  // First, iterate primary index.
  size_t primary_index_entries_count = 0;
  {
-    char buf[4];
-    EncodeFixed32(buf, Record::kPrimaryIndexId + 1);
-    std::reverse(buf, buf + sizeof(buf));
-    std::string iter_ub_str(buf, sizeof(buf));
+    std::string iter_ub_str;
+    PutFixed32(&iter_ub_str, Record::kPrimaryIndexId + 1);
+    std::reverse(iter_ub_str.begin(), iter_ub_str.end());
    Slice iter_ub = iter_ub_str;

+    std::string start_key;
+    PutFixed32(&start_key, Record::kPrimaryIndexId);
+    std::reverse(start_key.begin(), start_key.end());
+
    // This `ReadOptions` is for validation purposes. Ignore
    // `FLAGS_rate_limit_user_ops` to avoid slowing any validation.
    ReadOptions ropts;
@ -1064,7 +1145,7 @@ void MultiOpsTxnsStressTest::VerifyDb(ThreadState* thread) const {
    ropts.iterate_upper_bound = &iter_ub;

    std::unique_ptr<Iterator> it(db_->NewIterator(ropts));
-    for (it->SeekToFirst(); it->Valid(); it->Next()) {
+    for (it->Seek(start_key); it->Valid(); it->Next()) {
      Record record;
      Status s = record.DecodePrimaryIndexEntry(it->key(), it->value());
      if (!s.ok()) {
@ -1101,10 +1182,9 @@ void MultiOpsTxnsStressTest::VerifyDb(ThreadState* thread) const {
  // Second, iterate secondary index.
  size_t secondary_index_entries_count = 0;
  {
-    char buf[4];
-    EncodeFixed32(buf, Record::kSecondaryIndexId);
-    std::reverse(buf, buf + sizeof(buf));
-    const std::string start_key(buf, sizeof(buf));
+    std::string start_key;
+    PutFixed32(&start_key, Record::kSecondaryIndexId);
+    std::reverse(start_key.begin(), start_key.end());

    // This `ReadOptions` is for validation purposes. Ignore
    // `FLAGS_rate_limit_user_ops` to avoid slowing any validation.
@ -1118,7 +1198,8 @@ void MultiOpsTxnsStressTest::VerifyDb(ThreadState* thread) const {
      Record record;
      Status s = record.DecodeSecondaryIndexEntry(it->key(), it->value());
      if (!s.ok()) {
-        oss << "Cannot decode secondary index entry";
+        oss << "Cannot decode secondary index entry "
+            << it->key().ToString(true) << "=>" << it->value().ToString(true);
        VerificationAbort(thread->shared, oss.str(), s);
        assert(false);
        return;
@ -1132,7 +1213,7 @@ void MultiOpsTxnsStressTest::VerifyDb(ThreadState* thread) const {
      s = db_->Get(ropts, pk, &value);
      if (!s.ok()) {
        oss << "Error searching pk " << Slice(pk).ToString(true) << ". "
-            << s.ToString();
+            << s.ToString() << ". sk " << it->key().ToString(true);
        VerificationAbort(thread->shared, oss.str(), s);
        assert(false);
        return;
@ -1148,8 +1229,10 @@ void MultiOpsTxnsStressTest::VerifyDb(ThreadState* thread) const {
      }
      uint32_t c_in_primary = std::get<2>(result);
      if (c_in_primary != record.c_value()) {
-        oss << "Pk/sk mismatch. pk: (c=" << c_in_primary
-            << "), sk: (c=" << record.c_value() << ")";
+        oss << "Pk/sk mismatch. pk: " << Slice(pk).ToString(true) << "=>"
+            << Slice(value).ToString(true) << " (a=" << record.a_value()
+            << ", c=" << c_in_primary << "), sk: " << it->key().ToString(true)
+            << " (c=" << record.c_value() << ")";
        VerificationAbort(thread->shared, oss.str(), s);
        assert(false);
        return;
@ -1167,6 +1250,75 @@ void MultiOpsTxnsStressTest::VerifyDb(ThreadState* thread) const {
  }
 }

+void MultiOpsTxnsStressTest::VerifyPkSkFast(int job_id) {
+  const Snapshot* const snapshot = db_->GetSnapshot();
+  assert(snapshot);
+  ManagedSnapshot snapshot_guard(db_, snapshot);
+
+  std::ostringstream oss;
+  auto* dbimpl = static_cast_with_check<DBImpl>(db_->GetRootDB());
+  assert(dbimpl);
+
+  oss << "Job " << job_id << ": [" << snapshot->GetSequenceNumber() << ","
+      << dbimpl->GetLastPublishedSequence() << "] ";
+
+  std::string start_key;
+  PutFixed32(&start_key, Record::kSecondaryIndexId);
+  std::reverse(start_key.begin(), start_key.end());
+
+  // This `ReadOptions` is for validation purposes. Ignore
+  // `FLAGS_rate_limit_user_ops` to avoid slowing any validation.
+  ReadOptions ropts;
+  ropts.snapshot = snapshot;
+  ropts.total_order_seek = true;
+
+  std::unique_ptr<Iterator> it(db_->NewIterator(ropts));
+  for (it->Seek(start_key); it->Valid(); it->Next()) {
+    Record record;
+    Status s = record.DecodeSecondaryIndexEntry(it->key(), it->value());
+    if (!s.ok()) {
+      oss << "Cannot decode secondary index entry " << it->key().ToString(true)
+          << "=>" << it->value().ToString(true);
+      fprintf(stderr, "%s\n", oss.str().c_str());
+      fflush(stderr);
+      assert(false);
+    }
+    // After decoding secondary index entry, we know a and c. Crc is verified
+    // in decoding phase.
+    //
+    // Form a primary key and search in the primary index.
+    std::string pk = Record::EncodePrimaryKey(record.a_value());
+    std::string value;
+    s = db_->Get(ropts, pk, &value);
+    if (!s.ok()) {
+      oss << "Error searching pk " << Slice(pk).ToString(true) << ". "
+          << s.ToString() << ". sk " << it->key().ToString(true);
+      fprintf(stderr, "%s\n", oss.str().c_str());
+      fflush(stderr);
+      assert(false);
+    }
+    auto result = Record::DecodePrimaryIndexValue(value);
+    s = std::get<0>(result);
+    if (!s.ok()) {
+      oss << "Error decoding primary index value "
+          << Slice(value).ToString(true) << ". " << s.ToString();
+      fprintf(stderr, "%s\n", oss.str().c_str());
+      fflush(stderr);
+      assert(false);
+    }
+    uint32_t c_in_primary = std::get<2>(result);
+    if (c_in_primary != record.c_value()) {
+      oss << "Pk/sk mismatch. pk: " << Slice(pk).ToString(true) << "=>"
+          << Slice(value).ToString(true) << " (a=" << record.a_value()
+          << ", c=" << c_in_primary << "), sk: " << it->key().ToString(true)
+          << " (c=" << record.c_value() << ")";
+      fprintf(stderr, "%s\n", oss.str().c_str());
+      fflush(stderr);
+      assert(false);
+    }
+  }
+}
+
 std::pair<uint32_t, uint32_t> MultiOpsTxnsStressTest::ChooseExistingA(
    ThreadState* thread) {
  uint32_t tid = thread->tid;
@ -1193,6 +1345,22 @@ uint32_t MultiOpsTxnsStressTest::GenerateNextC(ThreadState* thread) {
  return key_gen->Allocate();
 }

+#ifndef ROCKSDB_LITE
+Status MultiOpsTxnsStressTest::WriteToCommitTimeWriteBatch(Transaction& txn) {
+  WriteBatch* ctwb = txn.GetCommitTimeWriteBatch();
+  assert(ctwb);
+  // Do not change the content in key_buf.
+  static constexpr char key_buf[sizeof(Record::kMetadataPrefix) + 4] = {
+      '\0', '\0', '\0', '\0', '\0', '\0', '\0', '\xff'};
+
+  uint64_t counter_val = counter_.Next();
+  char val_buf[sizeof(counter_val)];
+  EncodeFixed64(val_buf, counter_val);
+  return ctwb->Put(Slice(key_buf, sizeof(key_buf)),
+                   Slice(val_buf, sizeof(val_buf)));
+}
+#endif  // !ROCKSDB_LITE
+
 std::string MultiOpsTxnsStressTest::KeySpaces::EncodeTo() const {
  std::string result;
  PutFixed32(&result, lb_a);
@ -1428,8 +1596,9 @@ void MultiOpsTxnsStressTest::ScanExistingDb(SharedState* shared, int threads) {
      Record record;
      Status s = record.DecodePrimaryIndexEntry(it->key(), it->value());
      if (!s.ok()) {
-        fprintf(stderr, "Cannot decode primary index entry: %s\n",
-                s.ToString().c_str());
+        fprintf(stderr, "Cannot decode primary index entry (%s => %s): %s\n",
+                it->key().ToString(true).c_str(),
+                it->value().ToString(true).c_str(), s.ToString().c_str());
        assert(false);
      }
      uint32_t a = record.a_value();
--- a/db_stress_tool/multi_ops_txns_stress.h
+++ b/db_stress_tool/multi_ops_txns_stress.h
@ -111,6 +111,7 @@ class MultiOpsTxnsStressTest : public StressTest {
 public:
  class Record {
   public:
+    static constexpr uint32_t kMetadataPrefix = 0;
    static constexpr uint32_t kPrimaryIndexId = 1;
    static constexpr uint32_t kSecondaryIndexId = 2;

@ -261,6 +262,12 @@ class MultiOpsTxnsStressTest : public StressTest {
      ThreadState* thread,
      const std::vector<int>& rand_column_families) override;

+  void RegisterAdditionalListeners() override;
+
+#ifndef ROCKSDB_LITE
+  void PrepareTxnDbOptions(TransactionDBOptions& txn_db_opts) override;
+#endif  // !ROCKSDB_LITE
+
  Status PrimaryKeyUpdateTxn(ThreadState* thread, uint32_t old_a,
                             uint32_t old_a_pos, uint32_t new_a);

@ -280,7 +287,17 @@ class MultiOpsTxnsStressTest : public StressTest {
    VerifyDb(thread);
  }

+  void VerifyPkSkFast(int job_id);
+
 protected:
+  class Counter {
+   public:
+    uint64_t Next() { return value_.fetch_add(1); }
+
+   private:
+    std::atomic<uint64_t> value_ = Env::Default()->NowNanos();
+  };
+
  using KeySet = std::set<uint32_t>;
  class KeyGenerator {
   public:
@ -330,9 +347,21 @@ class MultiOpsTxnsStressTest : public StressTest {

  uint32_t GenerateNextC(ThreadState* thread);

+#ifndef ROCKSDB_LITE
+  // Some applications, e.g. MyRocks writes a KV pair to the database via
+  // commit-time-write-batch (ctwb) in additional to the transaction's regular
+  // write batch. The key is usually constant representing some system
+  // metadata, while the value is monoticailly increasing which represents the
+  // actual value of the metadata. Method WriteToCommitTimeWriteBatch()
+  // emulates this scenario.
+  Status WriteToCommitTimeWriteBatch(Transaction& txn);
+#endif  //! ROCKSDB_LITE
+
  std::vector<std::unique_ptr<KeyGenerator>> key_gen_for_a_;
  std::vector<std::unique_ptr<KeyGenerator>> key_gen_for_c_;

+  Counter counter_{};
+
 private:
  struct KeySpaces {
    uint32_t lb_a = 0;
@ -370,5 +399,38 @@ class InvariantChecker {
                "MultiOpsTxnsStressTest::Record::c_ must be 4 bytes");
 };

+class MultiOpsTxnsStressListener : public EventListener {
+ public:
+  explicit MultiOpsTxnsStressListener(MultiOpsTxnsStressTest* stress_test)
+      : stress_test_(stress_test) {
+    assert(stress_test_);
+  }
+
+#ifndef ROCKSDB_LITE
+  ~MultiOpsTxnsStressListener() override {}
+
+  void OnFlushCompleted(DB* db, const FlushJobInfo& info) override {
+    assert(db);
+#ifdef NDEBUG
+    (void)db;
+#endif
+    assert(info.cf_id == 0);
+    stress_test_->VerifyPkSkFast(info.job_id);
+  }
+
+  void OnCompactionCompleted(DB* db, const CompactionJobInfo& info) override {
+    assert(db);
+#ifdef NDEBUG
+    (void)db;
+#endif
+    assert(info.cf_id == 0);
+    stress_test_->VerifyPkSkFast(info.job_id);
+  }
+#endif  //! ROCKSDB_LITE
+
+ private:
+  MultiOpsTxnsStressTest* const stress_test_ = nullptr;
+};
+
 }  // namespace ROCKSDB_NAMESPACE
 #endif  // GFLAGS
--- a/tools/db_crashtest.py
+++ b/tools/db_crashtest.py
@ -383,6 +383,7 @@ multiops_txn_default_params = {
    # compactions.
    "flush_one_in": 1000,
    "key_spaces_path": setup_multiops_txn_key_spaces_file(),
+    "rollback_one_in":  4,
 }

 multiops_wc_txn_params = {
@ -401,6 +402,10 @@ multiops_wp_txn_params = {
    "enable_pipelined_write": 0,
    # OpenReadOnly after checkpoint is not currnetly compatible with WritePrepared txns
    "checkpoint_one_in": 0,
+    # Required to be 1 in order to use commit-time-batch
+    "use_only_the_last_commit_time_batch_for_recovery": 1,
+    "recycle_log_file_num": 0,
+    "clear_wp_commit_cache_one_in": 10,
 }

 def finalize_and_sanitize(src_params):
--- a/utilities/transactions/write_prepared_txn_db.cc
+++ b/utilities/transactions/write_prepared_txn_db.cc
@ -26,6 +26,18 @@
 #include "utilities/transactions/pessimistic_transaction.h"
 #include "utilities/transactions/transaction_db_mutex_impl.h"

+// This function is for testing only. If it returns true, then all entries in
+// the commit cache will be evicted. Unit and/or stress tests (db_stress)
+// can implement this function and customize how frequently commit cache
+// eviction occurs.
+// TODO: remove this function once we can configure commit cache to be very
+// small so that eviction occurs very frequently. This requires the commit
+// cache entry to be able to encode prepare and commit sequence numbers so that
+// the commit sequence number does not have to be within a certain range of
+// prepare sequence number.
+extern "C" bool rocksdb_write_prepared_TEST_ShouldClearCommitCache(void)
+    __attribute__((__weak__));
+
 namespace ROCKSDB_NAMESPACE {

 Status WritePreparedTxnDB::Initialize(
@ -505,6 +517,12 @@ void WritePreparedTxnDB::AddCommitted(uint64_t prepare_seq, uint64_t commit_seq,
        // legit when a commit entry in a write batch overwrite the previous one
        max_evicted_seq = evicted.commit_seq;
      }
+#ifdef OS_LINUX
+      if (rocksdb_write_prepared_TEST_ShouldClearCommitCache &&
+          rocksdb_write_prepared_TEST_ShouldClearCommitCache()) {
+        max_evicted_seq = last;
+      }
+#endif  // OS_LINUX
      ROCKS_LOG_DETAILS(info_log_,
                        "%lu Evicting %" PRIu64 ",%" PRIu64 " with max %" PRIu64
                        " => %lu",
--- a/utilities/transactions/write_prepared_txn_db.h
+++ b/utilities/transactions/write_prepared_txn_db.h
@ -513,6 +513,7 @@ class WritePreparedTxnDB : public PessimisticTransactionDB {
  friend class WriteUnpreparedTxn;
  friend class WriteUnpreparedTxnDB;
  friend class WriteUnpreparedTransactionTest_RecoveryTest_Test;
+  friend class MultiOpsTxnsStressTest;

  void Init(const TransactionDBOptions& txn_db_opts);