rocksdb/db/db_write_test.cc
Sergei Glushchenko 39c6c5fc1b Expose DB methods to lock and unlock the WAL (#5146)
Summary:
Expose DB methods to lock and unlock the WAL.

These methods are intended to use by MyRocks in order to obtain WAL
coordinates in consistent way.

Usage scenario is following:

MySQL has performance_schema.log_status which provides information that
enables a backup tool to copy the required log files without locking for
the duration of copy. To populate this table MySQL does following:

1. Lock the binary log. Transactions are not allowed to commit now
2. Save the binary log coordinates
3. Walk through the storage engines and lock writes on each engine. For
   InnoDB, redo log is locked. For MyRocks, WAL should be locked.
4. Ask storage engines for their coordinates. InnoDB reports its current
   LSN and checkpoint LSN. MyRocks should report active WAL files names
   and sizes.
5. Release storage engine's locks
6. Unlock binary log

Backup tool will then use this information to copy InnoDB, RocksDB and
MySQL binary logs up to specified positions to end up with consistent DB
state after restore.

Currently, RocksDB allows to obtain the list of WAL files. Only missing
bit is the method to lock the writes to WAL files.

LockWAL method must flush the WAL in order for the reported size to be
accurate (GetSortedWALFiles is using file system stat call to return the
file size), also, since backup tool is going to copy the WAL, it is
better to be flushed.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5146

Differential Revision: D14815447

Pulled By: maysamyabandeh

fbshipit-source-id: eec9535a6025229ed471119f19fe7b3d8ae888a3
2019-04-06 06:40:36 -07:00

200 lines
6.7 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).
#include <atomic>
#include <memory>
#include <thread>
#include <vector>
#include "db/db_test_util.h"
#include "db/write_batch_internal.h"
#include "db/write_thread.h"
#include "port/port.h"
#include "port/stack_trace.h"
#include "util/fault_injection_test_env.h"
#include "util/string_util.h"
#include "util/sync_point.h"
namespace rocksdb {
// Test variations of WriteImpl.
class DBWriteTest : public DBTestBase, public testing::WithParamInterface<int> {
public:
DBWriteTest() : DBTestBase("/db_write_test") {}
Options GetOptions() { return DBTestBase::GetOptions(GetParam()); }
void Open() { DBTestBase::Reopen(GetOptions()); }
};
// It is invalid to do sync write while disabling WAL.
TEST_P(DBWriteTest, SyncAndDisableWAL) {
WriteOptions write_options;
write_options.sync = true;
write_options.disableWAL = true;
ASSERT_TRUE(dbfull()->Put(write_options, "foo", "bar").IsInvalidArgument());
WriteBatch batch;
ASSERT_OK(batch.Put("foo", "bar"));
ASSERT_TRUE(dbfull()->Write(write_options, &batch).IsInvalidArgument());
}
TEST_P(DBWriteTest, IOErrorOnWALWritePropagateToWriteThreadFollower) {
constexpr int kNumThreads = 5;
std::unique_ptr<FaultInjectionTestEnv> mock_env(
new FaultInjectionTestEnv(Env::Default()));
Options options = GetOptions();
options.env = mock_env.get();
Reopen(options);
std::atomic<int> ready_count{0};
std::atomic<int> leader_count{0};
std::vector<port::Thread> threads;
mock_env->SetFilesystemActive(false);
// Wait until all threads linked to write threads, to make sure
// all threads join the same batch group.
SyncPoint::GetInstance()->SetCallBack(
"WriteThread::JoinBatchGroup:Wait", [&](void* arg) {
ready_count++;
auto* w = reinterpret_cast<WriteThread::Writer*>(arg);
if (w->state == WriteThread::STATE_GROUP_LEADER) {
leader_count++;
while (ready_count < kNumThreads) {
// busy waiting
}
}
});
SyncPoint::GetInstance()->EnableProcessing();
for (int i = 0; i < kNumThreads; i++) {
threads.push_back(port::Thread(
[&](int index) {
// All threads should fail.
auto res = Put("key" + ToString(index), "value");
if (options.manual_wal_flush) {
ASSERT_TRUE(res.ok());
// we should see fs error when we do the flush
// TSAN reports a false alarm for lock-order-inversion but Open and
// FlushWAL are not run concurrently. Disabling this until TSAN is
// fixed.
// res = dbfull()->FlushWAL(false);
// ASSERT_FALSE(res.ok());
} else {
ASSERT_FALSE(res.ok());
}
},
i));
}
for (int i = 0; i < kNumThreads; i++) {
threads[i].join();
}
ASSERT_EQ(1, leader_count);
// Close before mock_env destruct.
Close();
}
TEST_P(DBWriteTest, ManualWalFlushInEffect) {
Options options = GetOptions();
Reopen(options);
// try the 1st WAL created during open
ASSERT_TRUE(Put("key" + ToString(0), "value").ok());
ASSERT_TRUE(options.manual_wal_flush != dbfull()->TEST_WALBufferIsEmpty());
ASSERT_TRUE(dbfull()->FlushWAL(false).ok());
ASSERT_TRUE(dbfull()->TEST_WALBufferIsEmpty());
// try the 2nd wal created during SwitchWAL
dbfull()->TEST_SwitchWAL();
ASSERT_TRUE(Put("key" + ToString(0), "value").ok());
ASSERT_TRUE(options.manual_wal_flush != dbfull()->TEST_WALBufferIsEmpty());
ASSERT_TRUE(dbfull()->FlushWAL(false).ok());
ASSERT_TRUE(dbfull()->TEST_WALBufferIsEmpty());
}
TEST_P(DBWriteTest, IOErrorOnWALWriteTriggersReadOnlyMode) {
std::unique_ptr<FaultInjectionTestEnv> mock_env(
new FaultInjectionTestEnv(Env::Default()));
Options options = GetOptions();
options.env = mock_env.get();
Reopen(options);
for (int i = 0; i < 2; i++) {
// Forcibly fail WAL write for the first Put only. Subsequent Puts should
// fail due to read-only mode
mock_env->SetFilesystemActive(i != 0);
auto res = Put("key" + ToString(i), "value");
// TSAN reports a false alarm for lock-order-inversion but Open and
// FlushWAL are not run concurrently. Disabling this until TSAN is
// fixed.
/*
if (options.manual_wal_flush && i == 0) {
// even with manual_wal_flush the 2nd Put should return error because of
// the read-only mode
ASSERT_TRUE(res.ok());
// we should see fs error when we do the flush
res = dbfull()->FlushWAL(false);
}
*/
if (!options.manual_wal_flush) {
ASSERT_FALSE(res.ok());
}
}
// Close before mock_env destruct.
Close();
}
TEST_P(DBWriteTest, IOErrorOnSwitchMemtable) {
Random rnd(301);
std::unique_ptr<FaultInjectionTestEnv> mock_env(
new FaultInjectionTestEnv(Env::Default()));
Options options = GetOptions();
options.env = mock_env.get();
options.writable_file_max_buffer_size = 4 * 1024 * 1024;
options.write_buffer_size = 3 * 512 * 1024;
options.wal_bytes_per_sync = 256 * 1024;
options.manual_wal_flush = true;
Reopen(options);
mock_env->SetFilesystemActive(false, Status::IOError("Not active"));
Status s;
for (int i = 0; i < 4 * 512; ++i) {
s = Put(Key(i), RandomString(&rnd, 1024));
if (!s.ok()) {
break;
}
}
ASSERT_EQ(s.severity(), Status::Severity::kFatalError);
mock_env->SetFilesystemActive(true);
// Close before mock_env destruct.
Close();
}
// Test that db->LockWAL() flushes the WAL after locking.
TEST_P(DBWriteTest, LockWalInEffect) {
Options options = GetOptions();
Reopen(options);
// try the 1st WAL created during open
ASSERT_OK(Put("key" + ToString(0), "value"));
ASSERT_TRUE(options.manual_wal_flush != dbfull()->TEST_WALBufferIsEmpty());
ASSERT_OK(dbfull()->LockWAL());
ASSERT_TRUE(dbfull()->TEST_WALBufferIsEmpty(false));
ASSERT_OK(dbfull()->UnlockWAL());
// try the 2nd wal created during SwitchWAL
dbfull()->TEST_SwitchWAL();
ASSERT_OK(Put("key" + ToString(0), "value"));
ASSERT_TRUE(options.manual_wal_flush != dbfull()->TEST_WALBufferIsEmpty());
ASSERT_OK(dbfull()->LockWAL());
ASSERT_TRUE(dbfull()->TEST_WALBufferIsEmpty(false));
ASSERT_OK(dbfull()->UnlockWAL());
}
INSTANTIATE_TEST_CASE_P(DBWriteTestInstance, DBWriteTest,
testing::Values(DBTestBase::kDefault,
DBTestBase::kConcurrentWALWrites,
DBTestBase::kPipelinedWrite));
} // namespace rocksdb
int main(int argc, char** argv) {
rocksdb::port::InstallStackTraceHandler();
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}