rocksdb/utilities/transactions/write_unprepared_transaction_test.cc
Manuel Ung a16e00b7b9 WriteUnPrepared Txn: Disable seek to snapshot optimization (#3955)
Summary:
This is implemented by extending ReadCallback with another function `MaxUnpreparedSequenceNumber` which returns the largest visible sequence number for the current transaction, if there is uncommitted data written to DB. Otherwise, it returns zero, indicating no uncommitted data.

There are the places where reads had to be modified.
- Get and Seek/Next was just updated to seek to max(snapshot_seq, MaxUnpreparedSequenceNumber()) instead, and iterate until a key was visible.
- Prev did not need need updates since it did not use the Seek to sequence number optimization. Assuming that locks were held when writing unprepared keys, and ValidateSnapshot runs, there should only be committed keys and unprepared keys of the current transaction, all of which are visible. Prev will simply iterate to get the last visible key.
- Reseeking to skip keys optimization was also disabled for write unprepared, since it's possible to hit the max_skip condition even while reseeking. There needs to be some way to resolve infinite looping in this case.
Closes https://github.com/facebook/rocksdb/pull/3955

Differential Revision: D8286688

Pulled By: lth

fbshipit-source-id: 25e42f47fdeb5f7accea0f4fd350ef35198caafe
2018-06-27 12:23:07 -07:00

208 lines
6.2 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#ifndef ROCKSDB_LITE
#ifndef __STDC_FORMAT_MACROS
#define __STDC_FORMAT_MACROS
#endif
#include "utilities/transactions/transaction_test.h"
#include "utilities/transactions/write_unprepared_txn.h"
#include "utilities/transactions/write_unprepared_txn_db.h"
namespace rocksdb {
class WriteUnpreparedTransactionTestBase : public TransactionTestBase {
public:
WriteUnpreparedTransactionTestBase(bool use_stackable_db,
bool two_write_queue,
TxnDBWritePolicy write_policy)
: TransactionTestBase(use_stackable_db, two_write_queue, write_policy){}
};
class WriteUnpreparedTransactionTest
: public WriteUnpreparedTransactionTestBase,
virtual public ::testing::WithParamInterface<
std::tuple<bool, bool, TxnDBWritePolicy>> {
public:
WriteUnpreparedTransactionTest()
: WriteUnpreparedTransactionTestBase(std::get<0>(GetParam()),
std::get<1>(GetParam()),
std::get<2>(GetParam())){}
};
INSTANTIATE_TEST_CASE_P(
WriteUnpreparedTransactionTest, WriteUnpreparedTransactionTest,
::testing::Values(std::make_tuple(false, false, WRITE_UNPREPARED),
std::make_tuple(false, true, WRITE_UNPREPARED)));
TEST_P(WriteUnpreparedTransactionTest, ReadYourOwnWrite) {
auto verify_state = [](Iterator* iter, const std::string& key,
const std::string& value) {
ASSERT_TRUE(iter->Valid());
ASSERT_OK(iter->status());
ASSERT_EQ(key, iter->key().ToString());
ASSERT_EQ(value, iter->value().ToString());
};
options.disable_auto_compactions = true;
ReOpen();
// The following tests checks whether reading your own write for
// a transaction works for write unprepared, when there are uncommitted
// values written into DB.
//
// Although the values written by DB::Put are technically committed, we add
// their seq num to unprep_seqs_ to pretend that they were written into DB
// as part of an unprepared batch, and then check if they are visible to the
// transaction.
auto snapshot0 = db->GetSnapshot();
ASSERT_OK(db->Put(WriteOptions(), "a", "v1"));
ASSERT_OK(db->Put(WriteOptions(), "b", "v2"));
auto snapshot2 = db->GetSnapshot();
ASSERT_OK(db->Put(WriteOptions(), "a", "v3"));
ASSERT_OK(db->Put(WriteOptions(), "b", "v4"));
auto snapshot4 = db->GetSnapshot();
ASSERT_OK(db->Put(WriteOptions(), "a", "v5"));
ASSERT_OK(db->Put(WriteOptions(), "b", "v6"));
auto snapshot6 = db->GetSnapshot();
ASSERT_OK(db->Put(WriteOptions(), "a", "v7"));
ASSERT_OK(db->Put(WriteOptions(), "b", "v8"));
auto snapshot8 = db->GetSnapshot();
TransactionOptions txn_options;
WriteOptions write_options;
Transaction* txn = db->BeginTransaction(write_options, txn_options);
WriteUnpreparedTxn* wup_txn = dynamic_cast<WriteUnpreparedTxn*>(txn);
ReadOptions roptions;
roptions.snapshot = snapshot0;
auto iter = txn->GetIterator(roptions);
// Test Get().
std::string value;
wup_txn->unprep_seqs_[snapshot2->GetSequenceNumber() + 1] =
snapshot4->GetSequenceNumber() - snapshot2->GetSequenceNumber();
ASSERT_OK(txn->Get(roptions, Slice("a"), &value));
ASSERT_EQ(value, "v3");
ASSERT_OK(txn->Get(roptions, Slice("b"), &value));
ASSERT_EQ(value, "v4");
wup_txn->unprep_seqs_[snapshot6->GetSequenceNumber() + 1] =
snapshot8->GetSequenceNumber() - snapshot6->GetSequenceNumber();
ASSERT_OK(txn->Get(roptions, Slice("a"), &value));
ASSERT_EQ(value, "v7");
ASSERT_OK(txn->Get(roptions, Slice("b"), &value));
ASSERT_EQ(value, "v8");
wup_txn->unprep_seqs_.clear();
// Test Next().
wup_txn->unprep_seqs_[snapshot2->GetSequenceNumber() + 1] =
snapshot4->GetSequenceNumber() - snapshot2->GetSequenceNumber();
iter->Seek("a");
verify_state(iter, "a", "v3");
iter->Next();
verify_state(iter, "b", "v4");
iter->SeekToFirst();
verify_state(iter, "a", "v3");
iter->Next();
verify_state(iter, "b", "v4");
wup_txn->unprep_seqs_[snapshot6->GetSequenceNumber() + 1] =
snapshot8->GetSequenceNumber() - snapshot6->GetSequenceNumber();
iter->Seek("a");
verify_state(iter, "a", "v7");
iter->Next();
verify_state(iter, "b", "v8");
iter->SeekToFirst();
verify_state(iter, "a", "v7");
iter->Next();
verify_state(iter, "b", "v8");
wup_txn->unprep_seqs_.clear();
// Test Prev(). For Prev(), we need to adjust the snapshot to match what is
// possible in WriteUnpreparedTxn.
//
// Because of row locks and ValidateSnapshot, there cannot be any committed
// entries after snapshot, but before the first prepared key.
delete iter;
roptions.snapshot = snapshot2;
iter = txn->GetIterator(roptions);
wup_txn->unprep_seqs_[snapshot2->GetSequenceNumber() + 1] =
snapshot4->GetSequenceNumber() - snapshot2->GetSequenceNumber();
iter->SeekForPrev("b");
verify_state(iter, "b", "v4");
iter->Prev();
verify_state(iter, "a", "v3");
iter->SeekToLast();
verify_state(iter, "b", "v4");
iter->Prev();
verify_state(iter, "a", "v3");
delete iter;
roptions.snapshot = snapshot6;
iter = txn->GetIterator(roptions);
wup_txn->unprep_seqs_[snapshot6->GetSequenceNumber() + 1] =
snapshot8->GetSequenceNumber() - snapshot6->GetSequenceNumber();
iter->SeekForPrev("b");
verify_state(iter, "b", "v8");
iter->Prev();
verify_state(iter, "a", "v7");
iter->SeekToLast();
verify_state(iter, "b", "v8");
iter->Prev();
verify_state(iter, "a", "v7");
db->ReleaseSnapshot(snapshot0);
db->ReleaseSnapshot(snapshot2);
db->ReleaseSnapshot(snapshot4);
db->ReleaseSnapshot(snapshot6);
db->ReleaseSnapshot(snapshot8);
delete iter;
delete txn;
}
} // 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