rocksdb/utilities/transactions/transaction_test.cc

//  Copyright (c) 2015, Facebook, Inc.  All rights reserved.
//  This source code is licensed under the BSD-style license found in the
//  LICENSE file in the root directory of this source tree. An additional grant
//  of patent rights can be found in the PATENTS file in the same directory.

#ifndef ROCKSDB_LITE

#include <string>

#include "rocksdb/db.h"
#include "rocksdb/utilities/transaction.h"
#include "rocksdb/utilities/transaction_db.h"
#include "util/logging.h"
#include "util/testharness.h"
#include "utilities/merge_operators.h"
#include "utilities/merge_operators/string_append/stringappend.h"

using std::string;

namespace rocksdb {

class TransactionTest : public testing::Test {
 public:
  TransactionDB* db;
  string dbname;
  Options options;

  TransactionDBOptions txn_db_options;

  TransactionTest() {
    options.create_if_missing = true;
    options.max_write_buffer_number = 2;
    options.merge_operator = MergeOperators::CreateFromStringId("stringappend");
    dbname = test::TmpDir() + "/transaction_testdb";

    DestroyDB(dbname, options);
    txn_db_options.transaction_lock_timeout = 0;
    txn_db_options.default_lock_timeout = 0;
    Status s = TransactionDB::Open(options, txn_db_options, dbname, &db);
    assert(s.ok());
  }

  ~TransactionTest() {
    delete db;
    DestroyDB(dbname, options);
  }
};

TEST_F(TransactionTest, SuccessTest) {
  WriteOptions write_options;
  ReadOptions read_options;
  string value;
  Status s;

  db->Put(write_options, Slice("foo"), Slice("bar"));
  db->Put(write_options, Slice("foo2"), Slice("bar"));

  Transaction* txn = db->BeginTransaction(write_options, TransactionOptions());
  ASSERT_TRUE(txn);

  ASSERT_EQ(0, txn->GetNumPuts());

  s = txn->GetForUpdate(read_options, "foo", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar");

  s = txn->Put(Slice("foo"), Slice("bar2"));
  ASSERT_OK(s);

  ASSERT_EQ(1, txn->GetNumPuts());

  s = txn->GetForUpdate(read_options, "foo", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar2");

  s = txn->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "foo", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar2");

  delete txn;
}

TEST_F(TransactionTest, WriteConflictTest) {
  WriteOptions write_options;
  ReadOptions read_options;
  string value;
  Status s;

  db->Put(write_options, "foo", "A");
  db->Put(write_options, "foo2", "B");

  Transaction* txn = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn);

  s = txn->Put("foo", "A2");
  ASSERT_OK(s);

  s = txn->Put("foo2", "B2");
  ASSERT_OK(s);

  // This Put outside of a transaction will conflict with the previous write
  s = db->Put(write_options, "foo", "xxx");
  ASSERT_TRUE(s.IsTimedOut());

  s = db->Get(read_options, "foo", &value);
  ASSERT_EQ(value, "A");

  s = txn->Commit();
  ASSERT_OK(s);

  db->Get(read_options, "foo", &value);
  ASSERT_EQ(value, "A2");
  db->Get(read_options, "foo2", &value);
  ASSERT_EQ(value, "B2");

  delete txn;
}

TEST_F(TransactionTest, WriteConflictTest2) {
  WriteOptions write_options;
  ReadOptions read_options;
  TransactionOptions txn_options;
  string value;
  Status s;

  db->Put(write_options, "foo", "bar");

  txn_options.set_snapshot = true;
  Transaction* txn = db->BeginTransaction(write_options, txn_options);
  ASSERT_TRUE(txn);

  // This Put outside of a transaction will conflict with a later write
  s = db->Put(write_options, "foo", "barz");
  ASSERT_OK(s);

  s = txn->Put("foo2", "X");
  ASSERT_OK(s);

  s = txn->Put("foo",
               "bar2");  // Conflicts with write done after snapshot taken
  ASSERT_TRUE(s.IsBusy());

  s = txn->Put("foo3", "Y");
  ASSERT_OK(s);

  s = db->Get(read_options, "foo", &value);
  ASSERT_EQ(value, "barz");

  ASSERT_EQ(2, txn->GetNumKeys());

  s = txn->Commit();
  ASSERT_OK(s);  // Txn should commit, but only write foo2 and foo3

  // Verify that transaction wrote foo2 and foo3 but not foo
  db->Get(read_options, "foo", &value);
  ASSERT_EQ(value, "barz");

  db->Get(read_options, "foo2", &value);
  ASSERT_EQ(value, "X");

  db->Get(read_options, "foo3", &value);
  ASSERT_EQ(value, "Y");

  delete txn;
}

TEST_F(TransactionTest, ReadConflictTest) {
  WriteOptions write_options;
  ReadOptions read_options, snapshot_read_options;
  TransactionOptions txn_options;
  string value;
  Status s;

  db->Put(write_options, "foo", "bar");
  db->Put(write_options, "foo2", "bar");

  txn_options.set_snapshot = true;
  Transaction* txn = db->BeginTransaction(write_options, txn_options);
  ASSERT_TRUE(txn);

  txn->SetSnapshot();
  snapshot_read_options.snapshot = txn->GetSnapshot();

  txn->GetForUpdate(snapshot_read_options, "foo", &value);
  ASSERT_EQ(value, "bar");

  // This Put outside of a transaction will conflict with the previous read
  s = db->Put(write_options, "foo", "barz");
  ASSERT_TRUE(s.IsTimedOut());

  s = db->Get(read_options, "foo", &value);
  ASSERT_EQ(value, "bar");

  s = txn->Get(read_options, "foo", &value);
  ASSERT_EQ(value, "bar");

  s = txn->Commit();
  ASSERT_OK(s);

  delete txn;
}

TEST_F(TransactionTest, TxnOnlyTest) {
  // Test to make sure transactions work when there are no other writes in an
  // empty db.

  WriteOptions write_options;
  ReadOptions read_options;
  string value;
  Status s;

  Transaction* txn = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn);

  s = txn->Put("x", "y");
  ASSERT_OK(s);

  s = txn->Commit();
  ASSERT_OK(s);

  delete txn;
}

TEST_F(TransactionTest, FlushTest) {
  WriteOptions write_options;
  ReadOptions read_options, snapshot_read_options;
  string value;
  Status s;

  db->Put(write_options, Slice("foo"), Slice("bar"));
  db->Put(write_options, Slice("foo2"), Slice("bar"));

  Transaction* txn = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn);

  snapshot_read_options.snapshot = txn->GetSnapshot();

  txn->GetForUpdate(snapshot_read_options, "foo", &value);
  ASSERT_EQ(value, "bar");

  s = txn->Put(Slice("foo"), Slice("bar2"));
  ASSERT_OK(s);

  txn->GetForUpdate(snapshot_read_options, "foo", &value);
  ASSERT_EQ(value, "bar2");

  // Put a random key so we have a memtable to flush
  s = db->Put(write_options, "dummy", "dummy");
  ASSERT_OK(s);

  // force a memtable flush
  FlushOptions flush_ops;
  db->Flush(flush_ops);

  s = txn->Commit();
  // txn should commit since the flushed table is still in MemtableList History
  ASSERT_OK(s);

  db->Get(read_options, "foo", &value);
  ASSERT_EQ(value, "bar2");

  delete txn;
}

TEST_F(TransactionTest, FlushTest2) {
  WriteOptions write_options;
  ReadOptions read_options, snapshot_read_options;
  TransactionOptions txn_options;
  string value;
  Status s;

  db->Put(write_options, Slice("foo"), Slice("bar"));
  db->Put(write_options, Slice("foo2"), Slice("bar"));

  txn_options.set_snapshot = true;
  Transaction* txn = db->BeginTransaction(write_options, txn_options);
  ASSERT_TRUE(txn);

  snapshot_read_options.snapshot = txn->GetSnapshot();

  txn->GetForUpdate(snapshot_read_options, "foo", &value);
  ASSERT_EQ(value, "bar");

  s = txn->Put(Slice("foo"), Slice("bar2"));
  ASSERT_OK(s);

  txn->GetForUpdate(snapshot_read_options, "foo", &value);
  ASSERT_EQ(value, "bar2");

  // Put a random key so we have a MemTable to flush
  s = db->Put(write_options, "dummy", "dummy");
  ASSERT_OK(s);

  // force a memtable flush
  FlushOptions flush_ops;
  db->Flush(flush_ops);

  // Put a random key so we have a MemTable to flush
  s = db->Put(write_options, "dummy", "dummy2");
  ASSERT_OK(s);

  // force a memtable flush
  db->Flush(flush_ops);

  s = db->Put(write_options, "dummy", "dummy3");
  ASSERT_OK(s);

  // force a memtable flush
  // Since our test db has max_write_buffer_number=2, this flush will cause
  // the first memtable to get purged from the MemtableList history.
  db->Flush(flush_ops);

  s = txn->Put("X", "Y");
  // Put should fail since MemTableList History is not older than the snapshot.
  ASSERT_TRUE(s.IsTryAgain());

  s = txn->Commit();
  ASSERT_OK(s);

  // Transaction should only write the keys that succeeded.
  s = db->Get(read_options, "foo", &value);
  ASSERT_EQ(value, "bar2");

  s = db->Get(read_options, "X", &value);
  ASSERT_TRUE(s.IsNotFound());

  delete txn;
}

TEST_F(TransactionTest, NoSnapshotTest) {
  WriteOptions write_options;
  ReadOptions read_options;
  string value;
  Status s;

  db->Put(write_options, "AAA", "bar");

  Transaction* txn = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn);

  // Modify key after transaction start
  db->Put(write_options, "AAA", "bar1");

  // Read and write without a snapshot
  txn->GetForUpdate(read_options, "AAA", &value);
  ASSERT_EQ(value, "bar1");
  s = txn->Put("AAA", "bar2");
  ASSERT_OK(s);

  // Should commit since read/write was done after data changed
  s = txn->Commit();
  ASSERT_OK(s);

  txn->GetForUpdate(read_options, "AAA", &value);
  ASSERT_EQ(value, "bar2");

  delete txn;
}

TEST_F(TransactionTest, MultipleSnapshotTest) {
  WriteOptions write_options;
  ReadOptions read_options, snapshot_read_options;
  string value;
  Status s;

  db->Put(write_options, "AAA", "bar");
  db->Put(write_options, "BBB", "bar");
  db->Put(write_options, "CCC", "bar");

  Transaction* txn = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn);

  db->Put(write_options, "AAA", "bar1");

  // Read and write without a snapshot
  txn->GetForUpdate(read_options, "AAA", &value);
  ASSERT_EQ(value, "bar1");
  s = txn->Put("AAA", "bar2");
  ASSERT_OK(s);

  // Modify BBB before snapshot is taken
  db->Put(write_options, "BBB", "bar1");

  txn->SetSnapshot();
  snapshot_read_options.snapshot = txn->GetSnapshot();

  // Read and write with snapshot
  txn->GetForUpdate(snapshot_read_options, "BBB", &value);
  ASSERT_EQ(value, "bar1");
  s = txn->Put("BBB", "bar2");
  ASSERT_OK(s);

  db->Put(write_options, "CCC", "bar1");

  // Set a new snapshot
  txn->SetSnapshot();
  snapshot_read_options.snapshot = txn->GetSnapshot();

  // Read and write with snapshot
  txn->GetForUpdate(snapshot_read_options, "CCC", &value);
  ASSERT_EQ(value, "bar1");
  s = txn->Put("CCC", "bar2");
  ASSERT_OK(s);

  s = txn->GetForUpdate(read_options, "AAA", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar2");
  s = txn->GetForUpdate(read_options, "BBB", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar2");
  s = txn->GetForUpdate(read_options, "CCC", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar2");

  s = db->Get(read_options, "AAA", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar1");
  s = db->Get(read_options, "BBB", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar1");
  s = db->Get(read_options, "CCC", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar1");

  s = txn->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "AAA", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar2");
  s = db->Get(read_options, "BBB", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar2");
  s = db->Get(read_options, "CCC", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "bar2");

  // verify that we track multiple writes to the same key at different snapshots
  delete txn;
  txn = db->BeginTransaction(write_options);

  // Potentially conflicting writes
  db->Put(write_options, "ZZZ", "zzz");
  db->Put(write_options, "XXX", "xxx");

  txn->SetSnapshot();

  TransactionOptions txn_options;
  txn_options.set_snapshot = true;
  Transaction* txn2 = db->BeginTransaction(write_options, txn_options);
  txn2->SetSnapshot();

  // This should not conflict in txn since the snapshot is later than the
  // previous write (spoiler alert:  it will later conflict with txn2).
  s = txn->Put("ZZZ", "zzzz");
  ASSERT_OK(s);

  s = txn->Commit();
  ASSERT_OK(s);

  delete txn;

  // This will conflict since the snapshot is earlier than another write to ZZZ
  s = txn2->Put("ZZZ", "xxxxx");
  ASSERT_TRUE(s.IsBusy());

  s = txn2->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "ZZZ", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "zzzz");

  delete txn2;
}

TEST_F(TransactionTest, ColumnFamiliesTest) {
  WriteOptions write_options;
  ReadOptions read_options, snapshot_read_options;
  TransactionOptions txn_options;
  string value;
  Status s;

  ColumnFamilyHandle *cfa, *cfb;
  ColumnFamilyOptions cf_options;

  // Create 2 new column families
  s = db->CreateColumnFamily(cf_options, "CFA", &cfa);
  ASSERT_OK(s);
  s = db->CreateColumnFamily(cf_options, "CFB", &cfb);
  ASSERT_OK(s);

  delete cfa;
  delete cfb;
  delete db;

  // open DB with three column families
  std::vector<ColumnFamilyDescriptor> column_families;
  // have to open default column family
  column_families.push_back(
      ColumnFamilyDescriptor(kDefaultColumnFamilyName, ColumnFamilyOptions()));
  // open the new column families
  column_families.push_back(
      ColumnFamilyDescriptor("CFA", ColumnFamilyOptions()));
  column_families.push_back(
      ColumnFamilyDescriptor("CFB", ColumnFamilyOptions()));

  std::vector<ColumnFamilyHandle*> handles;

  s = TransactionDB::Open(options, txn_db_options, dbname, column_families,
                          &handles, &db);
  ASSERT_OK(s);

  Transaction* txn = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn);

  txn->SetSnapshot();
  snapshot_read_options.snapshot = txn->GetSnapshot();

  txn_options.set_snapshot = true;
  Transaction* txn2 = db->BeginTransaction(write_options, txn_options);
  ASSERT_TRUE(txn2);

  // Write some data to the db
  WriteBatch batch;
  batch.Put("foo", "foo");
  batch.Put(handles[1], "AAA", "bar");
  batch.Put(handles[1], "AAAZZZ", "bar");
  s = db->Write(write_options, &batch);
  ASSERT_OK(s);
  db->Delete(write_options, handles[1], "AAAZZZ");

  // These keys do not conflict with existing writes since they're in
  // different column families
  s = txn->Delete("AAA");
  ASSERT_OK(s);
  s = txn->GetForUpdate(snapshot_read_options, handles[1], "foo", &value);
  ASSERT_TRUE(s.IsNotFound());
  Slice key_slice("AAAZZZ");
  Slice value_slices[2] = {Slice("bar"), Slice("bar")};
  s = txn->Put(handles[2], SliceParts(&key_slice, 1),
               SliceParts(value_slices, 2));
  ASSERT_OK(s);
  ASSERT_EQ(3, txn->GetNumKeys());

  s = txn->Commit();
  ASSERT_OK(s);
  s = db->Get(read_options, "AAA", &value);
  ASSERT_TRUE(s.IsNotFound());
  s = db->Get(read_options, handles[2], "AAAZZZ", &value);
  ASSERT_EQ(value, "barbar");

  Slice key_slices[3] = {Slice("AAA"), Slice("ZZ"), Slice("Z")};
  Slice value_slice("barbarbar");

  s = txn2->Delete(handles[2], "XXX");
  ASSERT_OK(s);
  s = txn2->Delete(handles[1], "XXX");
  ASSERT_OK(s);

  // This write will cause a conflict with the earlier batch write
  s = txn2->Put(handles[1], SliceParts(key_slices, 3),
                SliceParts(&value_slice, 1));
  ASSERT_TRUE(s.IsBusy());

  s = txn2->Commit();
  ASSERT_OK(s);
  s = db->Get(read_options, handles[1], "AAAZZZ", &value);
  ASSERT_EQ(value, "barbar");

  delete txn;
  delete txn2;

  txn = db->BeginTransaction(write_options, txn_options);
  snapshot_read_options.snapshot = txn->GetSnapshot();

  txn2 = db->BeginTransaction(write_options, txn_options);
  ASSERT_TRUE(txn);

  std::vector<ColumnFamilyHandle*> multiget_cfh = {handles[1], handles[2],
                                                   handles[0], handles[2]};
  std::vector<Slice> multiget_keys = {"AAA", "AAAZZZ", "foo", "foo"};
  std::vector<std::string> values(4);

  std::vector<Status> results = txn->MultiGetForUpdate(
      snapshot_read_options, multiget_cfh, multiget_keys, &values);
  ASSERT_OK(results[0]);
  ASSERT_OK(results[1]);
  ASSERT_OK(results[2]);
  ASSERT_TRUE(results[3].IsNotFound());
  ASSERT_EQ(values[0], "bar");
  ASSERT_EQ(values[1], "barbar");
  ASSERT_EQ(values[2], "foo");

  s = txn->SingleDelete(handles[2], "ZZZ");
  ASSERT_OK(s);
  s = txn->Put(handles[2], "ZZZ", "YYY");
  ASSERT_OK(s);
  s = txn->Put(handles[2], "ZZZ", "YYYY");
  ASSERT_OK(s);
  s = txn->Delete(handles[2], "ZZZ");
  ASSERT_OK(s);
  s = txn->Put(handles[2], "AAAZZZ", "barbarbar");
  ASSERT_OK(s);

  ASSERT_EQ(5, txn->GetNumKeys());

  // Txn should commit
  s = txn->Commit();
  ASSERT_OK(s);
  s = db->Get(read_options, handles[2], "ZZZ", &value);
  ASSERT_TRUE(s.IsNotFound());

  // Put a key which will conflict with the next txn using the previous snapshot
  db->Put(write_options, handles[2], "foo", "000");

  results = txn2->MultiGetForUpdate(snapshot_read_options, multiget_cfh,
                                    multiget_keys, &values);
  // All results should fail since there was a conflict
  ASSERT_TRUE(results[0].IsBusy());
  ASSERT_TRUE(results[1].IsBusy());
  ASSERT_TRUE(results[2].IsBusy());
  ASSERT_TRUE(results[3].IsBusy());

  s = db->Get(read_options, handles[2], "foo", &value);
  ASSERT_EQ(value, "000");

  s = txn2->Commit();
  ASSERT_OK(s);

  s = db->DropColumnFamily(handles[1]);
  ASSERT_OK(s);
  s = db->DropColumnFamily(handles[2]);
  ASSERT_OK(s);

  delete txn;
  delete txn2;

  for (auto handle : handles) {
    delete handle;
  }
}

TEST_F(TransactionTest, ColumnFamiliesTest2) {
  WriteOptions write_options;
  ReadOptions read_options, snapshot_read_options;
  TransactionOptions txn_options;
  string value;
  Status s;

  ColumnFamilyHandle *one, *two;
  ColumnFamilyOptions cf_options;

  // Create 2 new column families
  s = db->CreateColumnFamily(cf_options, "ONE", &one);
  ASSERT_OK(s);
  s = db->CreateColumnFamily(cf_options, "TWO", &two);
  ASSERT_OK(s);

  Transaction* txn1 = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn1);
  Transaction* txn2 = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn2);

  s = txn1->Put(one, "X", "1");
  ASSERT_OK(s);
  s = txn1->Put(two, "X", "2");
  ASSERT_OK(s);
  s = txn1->Put("X", "0");
  ASSERT_OK(s);

  s = txn2->Put(one, "X", "11");
  ASSERT_TRUE(s.IsTimedOut());

  s = txn1->Commit();
  ASSERT_OK(s);

  // Drop first column family
  s = db->DropColumnFamily(one);
  ASSERT_OK(s);

  // Should fail since column family was dropped.
  s = txn2->Commit();
  ASSERT_OK(s);

  delete txn1;
  txn1 = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn1);

  // Should fail since column family was dropped
  s = txn1->Put(one, "X", "111");
  ASSERT_TRUE(s.IsInvalidArgument());

  s = txn1->Put(two, "X", "222");
  ASSERT_OK(s);

  s = txn1->Put("X", "000");
  ASSERT_OK(s);

  s = txn1->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, two, "X", &value);
  ASSERT_OK(s);
  ASSERT_EQ("222", value);

  s = db->Get(read_options, "X", &value);
  ASSERT_OK(s);
  ASSERT_EQ("000", value);

  s = db->DropColumnFamily(two);
  ASSERT_OK(s);

  delete txn1;
  delete txn2;

  delete one;
  delete two;
}

TEST_F(TransactionTest, EmptyTest) {
  WriteOptions write_options;
  ReadOptions read_options;
  string value;
  Status s;

  s = db->Put(write_options, "aaa", "aaa");
  ASSERT_OK(s);

  Transaction* txn = db->BeginTransaction(write_options);
  s = txn->Commit();
  ASSERT_OK(s);
  delete txn;

  txn = db->BeginTransaction(write_options);
  txn->Rollback();
  delete txn;

  txn = db->BeginTransaction(write_options);
  s = txn->GetForUpdate(read_options, "aaa", &value);
  ASSERT_EQ(value, "aaa");

  s = txn->Commit();
  ASSERT_OK(s);
  delete txn;

  txn = db->BeginTransaction(write_options);
  txn->SetSnapshot();

  s = txn->GetForUpdate(read_options, "aaa", &value);
  ASSERT_EQ(value, "aaa");

  // Conflicts with previous GetForUpdate
  s = db->Put(write_options, "aaa", "xxx");
  ASSERT_TRUE(s.IsTimedOut());

  // transaction expired!
  s = txn->Commit();
  ASSERT_OK(s);
  delete txn;
}

TEST_F(TransactionTest, PredicateManyPreceders) {
  WriteOptions write_options;
  ReadOptions read_options1, read_options2;
  TransactionOptions txn_options;
  string value;
  Status s;

  txn_options.set_snapshot = true;
  Transaction* txn1 = db->BeginTransaction(write_options, txn_options);
  read_options1.snapshot = txn1->GetSnapshot();

  Transaction* txn2 = db->BeginTransaction(write_options);
  txn2->SetSnapshot();
  read_options2.snapshot = txn2->GetSnapshot();

  std::vector<Slice> multiget_keys = {"1", "2", "3"};
  std::vector<std::string> multiget_values;

  std::vector<Status> results =
      txn1->MultiGetForUpdate(read_options1, multiget_keys, &multiget_values);
  ASSERT_TRUE(results[1].IsNotFound());

  s = txn2->Put("2", "x");  // Conflict's with txn1's MultiGetForUpdate
  ASSERT_TRUE(s.IsTimedOut());

  txn2->Rollback();

  multiget_values.clear();
  results =
      txn1->MultiGetForUpdate(read_options1, multiget_keys, &multiget_values);
  ASSERT_TRUE(results[1].IsNotFound());

  s = txn1->Commit();
  ASSERT_OK(s);

  delete txn1;
  delete txn2;

  txn1 = db->BeginTransaction(write_options, txn_options);
  read_options1.snapshot = txn1->GetSnapshot();

  txn2 = db->BeginTransaction(write_options, txn_options);
  read_options2.snapshot = txn2->GetSnapshot();

  s = txn1->Put("4", "x");
  ASSERT_OK(s);

  s = txn2->Delete("4");  // conflict
  ASSERT_TRUE(s.IsTimedOut());

  s = txn1->Commit();
  ASSERT_OK(s);

  s = txn2->GetForUpdate(read_options2, "4", &value);
  ASSERT_TRUE(s.IsBusy());

  txn2->Rollback();

  delete txn1;
  delete txn2;
}

TEST_F(TransactionTest, LostUpdate) {
  WriteOptions write_options;
  ReadOptions read_options, read_options1, read_options2;
  TransactionOptions txn_options;
  string value;
  Status s;

  // Test 2 transactions writing to the same key in multiple orders and
  // with/without snapshots

  Transaction* txn1 = db->BeginTransaction(write_options);
  Transaction* txn2 = db->BeginTransaction(write_options);

  s = txn1->Put("1", "1");
  ASSERT_OK(s);

  s = txn2->Put("1", "2");  // conflict
  ASSERT_TRUE(s.IsTimedOut());

  s = txn2->Commit();
  ASSERT_OK(s);

  s = txn1->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "1", &value);
  ASSERT_OK(s);
  ASSERT_EQ("1", value);

  delete txn1;
  delete txn2;

  txn_options.set_snapshot = true;
  txn1 = db->BeginTransaction(write_options, txn_options);
  read_options1.snapshot = txn1->GetSnapshot();

  txn2 = db->BeginTransaction(write_options, txn_options);
  read_options2.snapshot = txn2->GetSnapshot();

  s = txn1->Put("1", "3");
  ASSERT_OK(s);
  s = txn2->Put("1", "4");  // conflict
  ASSERT_TRUE(s.IsTimedOut());

  s = txn1->Commit();
  ASSERT_OK(s);

  s = txn2->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "1", &value);
  ASSERT_OK(s);
  ASSERT_EQ("3", value);

  delete txn1;
  delete txn2;

  txn1 = db->BeginTransaction(write_options, txn_options);
  read_options1.snapshot = txn1->GetSnapshot();

  txn2 = db->BeginTransaction(write_options, txn_options);
  read_options2.snapshot = txn2->GetSnapshot();

  s = txn1->Put("1", "5");
  ASSERT_OK(s);

  s = txn1->Commit();
  ASSERT_OK(s);

  s = txn2->Put("1", "6");
  ASSERT_TRUE(s.IsBusy());
  s = txn2->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "1", &value);
  ASSERT_OK(s);
  ASSERT_EQ("5", value);

  delete txn1;
  delete txn2;

  txn1 = db->BeginTransaction(write_options, txn_options);
  read_options1.snapshot = txn1->GetSnapshot();

  txn2 = db->BeginTransaction(write_options, txn_options);
  read_options2.snapshot = txn2->GetSnapshot();

  s = txn1->Put("1", "7");
  ASSERT_OK(s);
  s = txn1->Commit();
  ASSERT_OK(s);

  txn2->SetSnapshot();
  s = txn2->Put("1", "8");
  ASSERT_OK(s);
  s = txn2->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "1", &value);
  ASSERT_OK(s);
  ASSERT_EQ("8", value);

  delete txn1;
  delete txn2;

  txn1 = db->BeginTransaction(write_options);
  txn2 = db->BeginTransaction(write_options);

  s = txn1->Put("1", "9");
  ASSERT_OK(s);
  s = txn1->Commit();
  ASSERT_OK(s);

  s = txn2->Put("1", "10");
  ASSERT_OK(s);
  s = txn2->Commit();
  ASSERT_OK(s);

  delete txn1;
  delete txn2;

  s = db->Get(read_options, "1", &value);
  ASSERT_OK(s);
  ASSERT_EQ(value, "10");
}

TEST_F(TransactionTest, UntrackedWrites) {
  WriteOptions write_options;
  ReadOptions read_options;
  string value;
  Status s;

  // Verify transaction rollback works for untracked keys.
  Transaction* txn = db->BeginTransaction(write_options);
  txn->SetSnapshot();

  s = txn->PutUntracked("untracked", "0");
  ASSERT_OK(s);
  txn->Rollback();
  s = db->Get(read_options, "untracked", &value);
  ASSERT_TRUE(s.IsNotFound());

  delete txn;
  txn = db->BeginTransaction(write_options);
  txn->SetSnapshot();

  s = db->Put(write_options, "untracked", "x");
  ASSERT_OK(s);

  // Untracked writes should succeed even though key was written after snapshot
  s = txn->PutUntracked("untracked", "1");
  ASSERT_OK(s);
  s = txn->MergeUntracked("untracked", "2");
  ASSERT_OK(s);
  s = txn->DeleteUntracked("untracked");
  ASSERT_OK(s);

  // Conflict
  s = txn->Put("untracked", "3");
  ASSERT_TRUE(s.IsBusy());

  s = txn->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "untracked", &value);
  ASSERT_TRUE(s.IsNotFound());

  delete txn;
}

TEST_F(TransactionTest, ExpiredTransaction) {
  WriteOptions write_options;
  ReadOptions read_options;
  TransactionOptions txn_options;
  string value;
  Status s;

  // Set txn expiration timeout to 0 microseconds (expires instantly)
  txn_options.expiration = 0;
  Transaction* txn1 = db->BeginTransaction(write_options, txn_options);

  s = txn1->Put("X", "1");
  ASSERT_OK(s);

  s = txn1->Put("Y", "1");
  ASSERT_OK(s);

  Transaction* txn2 = db->BeginTransaction(write_options);

  // txn2 should be able to write to X since txn1 has expired
  s = txn2->Put("X", "2");
  ASSERT_OK(s);

  s = txn2->Commit();
  ASSERT_OK(s);
  s = db->Get(read_options, "X", &value);
  ASSERT_OK(s);
  ASSERT_EQ("2", value);

  s = txn1->Put("Z", "1");
  ASSERT_OK(s);

  // txn1 should fail to commit since it is expired
  s = txn1->Commit();
  ASSERT_TRUE(s.IsExpired());

  s = db->Get(read_options, "Y", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = db->Get(read_options, "Z", &value);
  ASSERT_TRUE(s.IsNotFound());

  delete txn1;
  delete txn2;
}

TEST_F(TransactionTest, Rollback) {
  WriteOptions write_options;
  ReadOptions read_options;
  TransactionOptions txn_options;
  string value;
  Status s;

  Transaction* txn1 = db->BeginTransaction(write_options, txn_options);

  ASSERT_OK(s);

  s = txn1->Put("X", "1");
  ASSERT_OK(s);

  Transaction* txn2 = db->BeginTransaction(write_options);

  // txn2 should not be able to write to X since txn1 has it locked
  s = txn2->Put("X", "2");
  ASSERT_TRUE(s.IsTimedOut());

  txn1->Rollback();
  delete txn1;

  // txn2 should now be able to write to X
  s = txn2->Put("X", "3");
  ASSERT_OK(s);

  s = txn2->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "X", &value);
  ASSERT_OK(s);
  ASSERT_EQ("3", value);

  delete txn2;
}

TEST_F(TransactionTest, LockLimitTest) {
  WriteOptions write_options;
  ReadOptions read_options, snapshot_read_options;
  TransactionOptions txn_options;
  string value;
  Status s;

  delete db;

  // Open DB with a lock limit of 3
  txn_db_options.max_num_locks = 3;
  s = TransactionDB::Open(options, txn_db_options, dbname, &db);
  ASSERT_OK(s);

  // Create a txn and verify we can only lock up to 3 keys
  Transaction* txn = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn);

  s = txn->Put("X", "x");
  ASSERT_OK(s);

  s = txn->Put("Y", "y");
  ASSERT_OK(s);

  s = txn->Put("Z", "z");
  ASSERT_OK(s);

  // lock limit reached
  s = txn->Put("W", "w");
  ASSERT_TRUE(s.IsBusy());

  // re-locking same key shouldn't put us over the limit
  s = txn->Put("X", "xx");
  ASSERT_OK(s);

  s = txn->GetForUpdate(read_options, "W", &value);
  ASSERT_TRUE(s.IsBusy());
  s = txn->GetForUpdate(read_options, "V", &value);
  ASSERT_TRUE(s.IsBusy());

  // re-locking same key shouldn't put us over the limit
  s = txn->GetForUpdate(read_options, "Y", &value);
  ASSERT_OK(s);
  ASSERT_EQ("y", value);

  s = txn->Get(read_options, "W", &value);
  ASSERT_TRUE(s.IsNotFound());

  Transaction* txn2 = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn2);

  // "X" currently locked
  s = txn2->Put("X", "x");
  ASSERT_TRUE(s.IsTimedOut());

  // lock limit reached
  s = txn2->Put("M", "m");
  ASSERT_TRUE(s.IsBusy());

  s = txn->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "X", &value);
  ASSERT_OK(s);
  ASSERT_EQ("xx", value);

  s = db->Get(read_options, "W", &value);
  ASSERT_TRUE(s.IsNotFound());

  // Committing txn should release its locks and allow txn2 to proceed
  s = txn2->Put("X", "x2");
  ASSERT_OK(s);

  s = txn2->Delete("X");
  ASSERT_OK(s);

  s = txn2->Put("M", "m");
  ASSERT_OK(s);

  s = txn2->Put("Z", "z2");
  ASSERT_OK(s);

  // lock limit reached
  s = txn2->Delete("Y");
  ASSERT_TRUE(s.IsBusy());

  s = txn2->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "Z", &value);
  ASSERT_OK(s);
  ASSERT_EQ("z2", value);

  s = db->Get(read_options, "Y", &value);
  ASSERT_OK(s);
  ASSERT_EQ("y", value);

  s = db->Get(read_options, "X", &value);
  ASSERT_TRUE(s.IsNotFound());

  delete txn;
  delete txn2;
}

TEST_F(TransactionTest, IteratorTest) {
  WriteOptions write_options;
  ReadOptions read_options, snapshot_read_options;
  TransactionOptions txn_options;
  string value;
  Status s;

  // Write some keys to the db
  s = db->Put(write_options, "A", "a");
  ASSERT_OK(s);

  s = db->Put(write_options, "G", "g");
  ASSERT_OK(s);

  s = db->Put(write_options, "F", "f");
  ASSERT_OK(s);

  s = db->Put(write_options, "C", "c");
  ASSERT_OK(s);

  s = db->Put(write_options, "D", "d");
  ASSERT_OK(s);

  Transaction* txn = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn);

  // Write some keys in a txn
  s = txn->Put("B", "b");
  ASSERT_OK(s);

  s = txn->Put("H", "h");
  ASSERT_OK(s);

  s = txn->Delete("D");
  ASSERT_OK(s);

  s = txn->Put("E", "e");
  ASSERT_OK(s);

  txn->SetSnapshot();
  const Snapshot* snapshot = txn->GetSnapshot();

  // Write some keys to the db after the snapshot
  s = db->Put(write_options, "BB", "xx");
  ASSERT_OK(s);

  s = db->Put(write_options, "C", "xx");
  ASSERT_OK(s);

  read_options.snapshot = snapshot;
  Iterator* iter = txn->GetIterator(read_options);
  ASSERT_OK(iter->status());
  iter->SeekToFirst();

  // Read all keys via iter and lock them all
  std::string results[] = {"a", "b", "c", "e", "f", "g", "h"};
  for (int i = 0; i < 7; i++) {
    ASSERT_OK(iter->status());
    ASSERT_TRUE(iter->Valid());
    ASSERT_EQ(results[i], iter->value().ToString());

    s = txn->GetForUpdate(read_options, iter->key(), nullptr);
    if (i == 2) {
      // "C" was modified after txn's snapshot
      ASSERT_TRUE(s.IsBusy());
    } else {
      ASSERT_OK(s);
    }

    iter->Next();
  }
  ASSERT_FALSE(iter->Valid());

  iter->Seek("G");
  ASSERT_OK(iter->status());
  ASSERT_TRUE(iter->Valid());
  ASSERT_EQ("g", iter->value().ToString());

  iter->Prev();
  ASSERT_OK(iter->status());
  ASSERT_TRUE(iter->Valid());
  ASSERT_EQ("f", iter->value().ToString());

  iter->Seek("D");
  ASSERT_OK(iter->status());
  ASSERT_TRUE(iter->Valid());
  ASSERT_EQ("e", iter->value().ToString());

  iter->Seek("C");
  ASSERT_OK(iter->status());
  ASSERT_TRUE(iter->Valid());
  ASSERT_EQ("c", iter->value().ToString());

  iter->Next();
  ASSERT_OK(iter->status());
  ASSERT_TRUE(iter->Valid());
  ASSERT_EQ("e", iter->value().ToString());

  iter->Seek("");
  ASSERT_OK(iter->status());
  ASSERT_TRUE(iter->Valid());
  ASSERT_EQ("a", iter->value().ToString());

  iter->Seek("X");
  ASSERT_OK(iter->status());
  ASSERT_FALSE(iter->Valid());

  iter->SeekToLast();
  ASSERT_OK(iter->status());
  ASSERT_TRUE(iter->Valid());
  ASSERT_EQ("h", iter->value().ToString());

  s = txn->Commit();
  ASSERT_OK(s);

  delete iter;
  delete txn;
}

TEST_F(TransactionTest, SavepointTest) {
  WriteOptions write_options;
  ReadOptions read_options, snapshot_read_options;
  TransactionOptions txn_options;
  string value;
  Status s;

  Transaction* txn = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn);

  ASSERT_EQ(0, txn->GetNumPuts());

  s = txn->RollbackToSavePoint();
  ASSERT_TRUE(s.IsNotFound());

  txn->SetSavePoint();  // 1

  ASSERT_OK(txn->RollbackToSavePoint());  // Rollback to beginning of txn
  s = txn->RollbackToSavePoint();
  ASSERT_TRUE(s.IsNotFound());

  s = txn->Put("B", "b");
  ASSERT_OK(s);

  ASSERT_EQ(1, txn->GetNumPuts());
  ASSERT_EQ(0, txn->GetNumDeletes());

  s = txn->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "B", &value);
  ASSERT_OK(s);
  ASSERT_EQ("b", value);

  delete txn;
  txn = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn);

  s = txn->Put("A", "a");
  ASSERT_OK(s);

  s = txn->Put("B", "bb");
  ASSERT_OK(s);

  s = txn->Put("C", "c");
  ASSERT_OK(s);

  txn->SetSavePoint();  // 2

  s = txn->Delete("B");
  ASSERT_OK(s);

  s = txn->Put("C", "cc");
  ASSERT_OK(s);

  s = txn->Put("D", "d");
  ASSERT_OK(s);

  ASSERT_EQ(5, txn->GetNumPuts());
  ASSERT_EQ(1, txn->GetNumDeletes());

  ASSERT_OK(txn->RollbackToSavePoint());  // Rollback to 2

  ASSERT_EQ(3, txn->GetNumPuts());
  ASSERT_EQ(0, txn->GetNumDeletes());

  s = txn->Get(read_options, "A", &value);
  ASSERT_OK(s);
  ASSERT_EQ("a", value);

  s = txn->Get(read_options, "B", &value);
  ASSERT_OK(s);
  ASSERT_EQ("bb", value);

  s = txn->Get(read_options, "C", &value);
  ASSERT_OK(s);
  ASSERT_EQ("c", value);

  s = txn->Get(read_options, "D", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = txn->Put("A", "a");
  ASSERT_OK(s);

  s = txn->Put("E", "e");
  ASSERT_OK(s);

  ASSERT_EQ(5, txn->GetNumPuts());
  ASSERT_EQ(0, txn->GetNumDeletes());

  // Rollback to beginning of txn
  s = txn->RollbackToSavePoint();
  ASSERT_TRUE(s.IsNotFound());
  txn->Rollback();

  ASSERT_EQ(0, txn->GetNumPuts());
  ASSERT_EQ(0, txn->GetNumDeletes());

  s = txn->Get(read_options, "A", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = txn->Get(read_options, "B", &value);
  ASSERT_OK(s);
  ASSERT_EQ("b", value);

  s = txn->Get(read_options, "D", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = txn->Get(read_options, "D", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = txn->Get(read_options, "E", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = txn->Put("A", "aa");
  ASSERT_OK(s);

  s = txn->Put("F", "f");
  ASSERT_OK(s);

  ASSERT_EQ(2, txn->GetNumPuts());
  ASSERT_EQ(0, txn->GetNumDeletes());

  txn->SetSavePoint();  // 3
  txn->SetSavePoint();  // 4

  s = txn->Put("G", "g");
  ASSERT_OK(s);

  s = txn->SingleDelete("F");
  ASSERT_OK(s);

  s = txn->Delete("B");
  ASSERT_OK(s);

  s = txn->Get(read_options, "A", &value);
  ASSERT_OK(s);
  ASSERT_EQ("aa", value);

  s = txn->Get(read_options, "F", &value);
  // According to db.h, doing a SingleDelete on a key that has been
  // overwritten will have undefinied behavior.  So it is unclear what the
  // result of fetching "F" should be. The current implementation will
  // return NotFound in this case.
  ASSERT_TRUE(s.IsNotFound());

  s = txn->Get(read_options, "B", &value);
  ASSERT_TRUE(s.IsNotFound());

  ASSERT_EQ(3, txn->GetNumPuts());
  ASSERT_EQ(2, txn->GetNumDeletes());

  ASSERT_OK(txn->RollbackToSavePoint());  // Rollback to 3

  ASSERT_EQ(2, txn->GetNumPuts());
  ASSERT_EQ(0, txn->GetNumDeletes());

  s = txn->Get(read_options, "F", &value);
  ASSERT_OK(s);
  ASSERT_EQ("f", value);

  s = txn->Get(read_options, "G", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = txn->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "F", &value);
  ASSERT_OK(s);
  ASSERT_EQ("f", value);

  s = db->Get(read_options, "G", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = db->Get(read_options, "A", &value);
  ASSERT_OK(s);
  ASSERT_EQ("aa", value);

  s = db->Get(read_options, "B", &value);
  ASSERT_OK(s);
  ASSERT_EQ("b", value);

  s = db->Get(read_options, "C", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = db->Get(read_options, "D", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = db->Get(read_options, "E", &value);
  ASSERT_TRUE(s.IsNotFound());

  delete txn;
}

TEST_F(TransactionTest, SavepointTest2) {
  WriteOptions write_options;
  ReadOptions read_options, snapshot_read_options;
  TransactionOptions txn_options;
  string value;
  Status s;

  txn_options.lock_timeout = 1;  // 1 ms
  Transaction* txn1 = db->BeginTransaction(write_options, txn_options);
  ASSERT_TRUE(txn1);

  s = txn1->Put("A", "");
  ASSERT_OK(s);

  txn1->SetSavePoint();  // 1

  s = txn1->Put("A", "a");
  ASSERT_OK(s);

  s = txn1->Put("C", "c");
  ASSERT_OK(s);

  txn1->SetSavePoint();  // 2

  s = txn1->Put("A", "a");
  ASSERT_OK(s);
  s = txn1->Put("B", "b");
  ASSERT_OK(s);

  ASSERT_OK(txn1->RollbackToSavePoint());  // Rollback to 2

  // Verify that "A" and "C" is still locked while "B" is not
  Transaction* txn2 = db->BeginTransaction(write_options, txn_options);
  ASSERT_TRUE(txn2);

  s = txn2->Put("A", "a2");
  ASSERT_TRUE(s.IsTimedOut());
  s = txn2->Put("C", "c2");
  ASSERT_TRUE(s.IsTimedOut());
  s = txn2->Put("B", "b2");
  ASSERT_OK(s);

  s = txn1->Put("A", "aa");
  ASSERT_OK(s);
  s = txn1->Put("B", "bb");
  ASSERT_TRUE(s.IsTimedOut());

  s = txn2->Commit();
  ASSERT_OK(s);
  delete txn2;

  s = txn1->Put("A", "aaa");
  ASSERT_OK(s);
  s = txn1->Put("B", "bbb");
  ASSERT_OK(s);
  s = txn1->Put("C", "ccc");
  ASSERT_OK(s);

  txn1->SetSavePoint();                    // 3
  ASSERT_OK(txn1->RollbackToSavePoint());  // Rollback to 3

  // Verify that "A", "B", "C" are still locked
  txn2 = db->BeginTransaction(write_options, txn_options);
  ASSERT_TRUE(txn2);

  s = txn2->Put("A", "a2");
  ASSERT_TRUE(s.IsTimedOut());
  s = txn2->Put("B", "b2");
  ASSERT_TRUE(s.IsTimedOut());
  s = txn2->Put("C", "c2");
  ASSERT_TRUE(s.IsTimedOut());

  ASSERT_OK(txn1->RollbackToSavePoint());  // Rollback to 1

  // Verify that only "A" is locked
  s = txn2->Put("A", "a3");
  ASSERT_TRUE(s.IsTimedOut());
  s = txn2->Put("B", "b3");
  ASSERT_OK(s);
  s = txn2->Put("C", "c3po");
  ASSERT_OK(s);

  s = txn1->Commit();
  ASSERT_OK(s);
  delete txn1;

  // Verify "A" "C" "B" are no longer locked
  s = txn2->Put("A", "a4");
  ASSERT_OK(s);
  s = txn2->Put("B", "b4");
  ASSERT_OK(s);
  s = txn2->Put("C", "c4");
  ASSERT_OK(s);

  s = txn2->Commit();
  ASSERT_OK(s);
  delete txn2;
}

TEST_F(TransactionTest, TimeoutTest) {
  WriteOptions write_options;
  ReadOptions read_options;
  string value;
  Status s;

  delete db;

  // transaction writes have an infinite timeout,
  // but we will override this when we start a txn
  // db writes have infinite timeout
  txn_db_options.transaction_lock_timeout = -1;
  txn_db_options.default_lock_timeout = -1;

  s = TransactionDB::Open(options, txn_db_options, dbname, &db);
  ASSERT_OK(s);

  s = db->Put(write_options, "aaa", "aaa");
  ASSERT_OK(s);

  TransactionOptions txn_options0;
  txn_options0.expiration = 100;  // 100ms
  txn_options0.lock_timeout = 50;  // txn timeout no longer infinite
  Transaction* txn1 = db->BeginTransaction(write_options, txn_options0);

  s = txn1->GetForUpdate(read_options, "aaa", nullptr);
  ASSERT_OK(s);

  // Conflicts with previous GetForUpdate.
  // Since db writes do not have a timeout, this should eventually succeed when
  // the transaction expires.
  s = db->Put(write_options, "aaa", "xxx");
  ASSERT_OK(s);

  ASSERT_GE(txn1->GetElapsedTime(),
            static_cast<uint64_t>(txn_options0.expiration));

  s = txn1->Commit();
  ASSERT_TRUE(s.IsExpired());  // expired!

  s = db->Get(read_options, "aaa", &value);
  ASSERT_OK(s);
  ASSERT_EQ("xxx", value);

  delete txn1;
  delete db;

  // transaction writes have 10ms timeout,
  // db writes have infinite timeout
  txn_db_options.transaction_lock_timeout = 50;
  txn_db_options.default_lock_timeout = -1;

  s = TransactionDB::Open(options, txn_db_options, dbname, &db);
  ASSERT_OK(s);

  s = db->Put(write_options, "aaa", "aaa");
  ASSERT_OK(s);

  TransactionOptions txn_options;
  txn_options.expiration = 100;  // 100ms
  txn1 = db->BeginTransaction(write_options, txn_options);

  s = txn1->GetForUpdate(read_options, "aaa", nullptr);
  ASSERT_OK(s);

  // Conflicts with previous GetForUpdate.
  // Since db writes do not have a timeout, this should eventually succeed when
  // the transaction expires.
  s = db->Put(write_options, "aaa", "xxx");
  ASSERT_OK(s);

  s = txn1->Commit();
  ASSERT_NOK(s);  // expired!

  s = db->Get(read_options, "aaa", &value);
  ASSERT_OK(s);
  ASSERT_EQ("xxx", value);

  delete txn1;
  txn_options.expiration = 6000000;  // 100 minutes
  txn_options.lock_timeout = 1;      // 1ms
  txn1 = db->BeginTransaction(write_options, txn_options);
  txn1->SetLockTimeout(100);

  TransactionOptions txn_options2;
  txn_options2.expiration = 10;  // 10ms
  Transaction* txn2 = db->BeginTransaction(write_options, txn_options2);
  ASSERT_OK(s);

  s = txn2->Put("a", "2");
  ASSERT_OK(s);

  // txn1 has a lock timeout longer than txn2's expiration, so it will win
  s = txn1->Delete("a");
  ASSERT_OK(s);

  s = txn1->Commit();
  ASSERT_OK(s);

  // txn2 should be expired out since txn1 waiting until its timeout expired.
  s = txn2->Commit();
  ASSERT_TRUE(s.IsExpired());

  delete txn1;
  delete txn2;
  txn_options.expiration = 6000000;  // 100 minutes
  txn1 = db->BeginTransaction(write_options, txn_options);
  txn_options2.expiration = 100000000;
  txn2 = db->BeginTransaction(write_options, txn_options2);

  s = txn1->Delete("asdf");
  ASSERT_OK(s);

  // txn2 has a smaller lock timeout than txn1's expiration, so it will time out
  s = txn2->Delete("asdf");
  ASSERT_TRUE(s.IsTimedOut());
  ASSERT_EQ(s.ToString(), "Operation timed out: Timeout waiting to lock key");

  s = txn1->Commit();
  ASSERT_OK(s);

  s = txn2->Put("asdf", "asdf");
  ASSERT_OK(s);

  s = txn2->Commit();
  ASSERT_OK(s);

  s = db->Get(read_options, "asdf", &value);
  ASSERT_OK(s);
  ASSERT_EQ("asdf", value);

  delete txn1;
  delete txn2;
}

TEST_F(TransactionTest, SingleDeleteTest) {
  WriteOptions write_options;
  ReadOptions read_options;
  string value;
  Status s;

  Transaction* txn = db->BeginTransaction(write_options);
  ASSERT_TRUE(txn);

  s = txn->SingleDelete("A");
  ASSERT_OK(s);

  s = txn->Get(read_options, "A", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = txn->Commit();
  ASSERT_OK(s);
  delete txn;

  txn = db->BeginTransaction(write_options);

  s = txn->SingleDelete("A");
  ASSERT_OK(s);

  s = txn->Put("A", "a");
  ASSERT_OK(s);

  s = txn->Get(read_options, "A", &value);
  ASSERT_OK(s);
  ASSERT_EQ("a", value);

  s = txn->Commit();
  ASSERT_OK(s);
  delete txn;

  s = db->Get(read_options, "A", &value);
  ASSERT_OK(s);
  ASSERT_EQ("a", value);

  txn = db->BeginTransaction(write_options);

  s = txn->SingleDelete("A");
  ASSERT_OK(s);

  s = txn->Get(read_options, "A", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = txn->Commit();
  ASSERT_OK(s);
  delete txn;

  s = db->Get(read_options, "A", &value);
  ASSERT_TRUE(s.IsNotFound());

  txn = db->BeginTransaction(write_options);
  Transaction* txn2 = db->BeginTransaction(write_options);
  txn2->SetSnapshot();

  s = txn->Put("A", "a");
  ASSERT_OK(s);

  s = txn->Put("A", "a2");
  ASSERT_OK(s);

  s = txn->SingleDelete("A");
  ASSERT_OK(s);

  s = txn->SingleDelete("B");
  ASSERT_OK(s);

  // According to db.h, doing a SingleDelete on a key that has been
  // overwritten will have undefinied behavior.  So it is unclear what the
  // result of fetching "A" should be. The current implementation will
  // return NotFound in this case.
  s = txn->Get(read_options, "A", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = txn2->Put("B", "b");
  ASSERT_TRUE(s.IsTimedOut());
  s = txn2->Commit();
  ASSERT_OK(s);
  delete txn2;

  s = txn->Commit();
  ASSERT_OK(s);
  delete txn;

  // According to db.h, doing a SingleDelete on a key that has been
  // overwritten will have undefinied behavior.  So it is unclear what the
  // result of fetching "A" should be. The current implementation will
  // return NotFound in this case.
  s = db->Get(read_options, "A", &value);
  ASSERT_TRUE(s.IsNotFound());

  s = db->Get(read_options, "B", &value);
  ASSERT_TRUE(s.IsNotFound());
}

TEST_F(TransactionTest, MergeTest) {
  WriteOptions write_options;
  ReadOptions read_options;
  string value;
  Status s;

  Transaction* txn = db->BeginTransaction(write_options, TransactionOptions());
  ASSERT_TRUE(txn);

  s = db->Put(write_options, "A", "a0");
  ASSERT_OK(s);

  s = txn->Merge("A", "1");
  ASSERT_OK(s);

  s = txn->Merge("A", "2");
  ASSERT_OK(s);

  s = txn->Get(read_options, "A", &value);
  ASSERT_TRUE(s.IsMergeInProgress());

  s = txn->Put("A", "a");
  ASSERT_OK(s);

  s = txn->Get(read_options, "A", &value);
  ASSERT_OK(s);
  ASSERT_EQ("a", value);

  s = txn->Merge("A", "3");
  ASSERT_OK(s);

  s = txn->Get(read_options, "A", &value);
  ASSERT_TRUE(s.IsMergeInProgress());

  TransactionOptions txn_options;
  txn_options.lock_timeout = 1;  // 1 ms
  Transaction* txn2 = db->BeginTransaction(write_options, txn_options);
  ASSERT_TRUE(txn2);

  // verify that txn has "A" locked
  s = txn2->Merge("A", "4");
  ASSERT_TRUE(s.IsTimedOut());

  s = txn2->Commit();
  ASSERT_OK(s);
  delete txn2;

  s = txn->Commit();
  ASSERT_OK(s);
  delete txn;

  s = db->Get(read_options, "A", &value);
  ASSERT_OK(s);
  ASSERT_EQ("a,3", value);
}

}  // namespace rocksdb

int main(int argc, char** argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}

#else
#include <stdio.h>

int main(int argc, char** argv) {
  fprintf(stderr,
          "SKIPPED as Transactions are not supported in ROCKSDB_LITE\n");
  return 0;
}

#endif  // ROCKSDB_LITE