rocksdb/db/cuckoo_table_db_test.cc
Cheng Chang 5e794b0841 Fix a recovery corner case (#7621)
Summary:
Consider the following sequence of events:

1. Db flushed an SST with file number N, appended to MANIFEST, and tried to sync the MANIFEST.
2. Syncing MANIFEST failed and db crashed.
3. Db tried to recover with this MANIFEST. In the meantime, no entry about the newly-flushed SST was found in the MANIFEST. Therefore, RocksDB replayed WAL and tried to flush to an SST file reusing the same file number N. This failed because file system does not support overwrite. Then Db deleted this file.
4. Db crashed again.
5. Db tried to recover. When db read the MANIFEST, there was an entry referencing N.sst. This could happen probably because the append in step 1 finally reached the MANIFEST and became visible. Since N.sst had been deleted in step 3, recovery failed.

It is possible that N.sst created in step 1 is valid. Although step 3 would still fail since the MANIFEST was not synced properly in step 1 and 2, deleting N.sst would make it impossible for the db to recover even if the remaining part of MANIFEST was appended and visible after step 5.

After this PR, in step 3, immediately after recovering from MANIFEST, a new MANIFEST is created, then we find that N.sst is not referenced in the MANIFEST, so we delete it, and we'll not reuse N as file number. Then in step 5, since the new MANIFEST does not contain N.sst, the recovery failure situation in step 5 won't happen.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/7621

Test Plan:
1. some tests are updated, because these tests assume that new MANIFEST is created after WAL recovery.
2. a new unit test is added in db_basic_test to simulate step 3.

Reviewed By: riversand963

Differential Revision: D24668144

Pulled By: cheng-chang

fbshipit-source-id: 90d7487fbad2bc3714f5ede46ea949895b15ae3b
2020-11-07 22:23:27 -08:00

360 lines
10 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
#include "db/db_impl/db_impl.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "table/cuckoo/cuckoo_table_factory.h"
#include "table/cuckoo/cuckoo_table_reader.h"
#include "table/meta_blocks.h"
#include "test_util/testharness.h"
#include "test_util/testutil.h"
#include "util/cast_util.h"
#include "util/string_util.h"
namespace ROCKSDB_NAMESPACE {
class CuckooTableDBTest : public testing::Test {
private:
std::string dbname_;
Env* env_;
DB* db_;
public:
CuckooTableDBTest() : env_(Env::Default()) {
dbname_ = test::PerThreadDBPath("cuckoo_table_db_test");
EXPECT_OK(DestroyDB(dbname_, Options()));
db_ = nullptr;
Reopen();
}
~CuckooTableDBTest() override {
delete db_;
EXPECT_OK(DestroyDB(dbname_, Options()));
}
Options CurrentOptions() {
Options options;
options.table_factory.reset(NewCuckooTableFactory());
options.memtable_factory.reset(NewHashLinkListRepFactory(4, 0, 3, true));
options.allow_mmap_reads = true;
options.create_if_missing = true;
options.allow_concurrent_memtable_write = false;
return options;
}
DBImpl* dbfull() { return static_cast_with_check<DBImpl>(db_); }
// The following util methods are copied from plain_table_db_test.
void Reopen(Options* options = nullptr) {
delete db_;
db_ = nullptr;
Options opts;
if (options != nullptr) {
opts = *options;
} else {
opts = CurrentOptions();
opts.create_if_missing = true;
}
ASSERT_OK(DB::Open(opts, dbname_, &db_));
}
void DestroyAndReopen(Options* options) {
assert(options);
ASSERT_OK(db_->Close());
delete db_;
db_ = nullptr;
ASSERT_OK(DestroyDB(dbname_, *options));
Reopen(options);
}
Status Put(const Slice& k, const Slice& v) {
return db_->Put(WriteOptions(), k, v);
}
Status Delete(const std::string& k) {
return db_->Delete(WriteOptions(), k);
}
std::string Get(const std::string& k) {
ReadOptions options;
std::string result;
Status s = db_->Get(options, k, &result);
if (s.IsNotFound()) {
result = "NOT_FOUND";
} else if (!s.ok()) {
result = s.ToString();
}
return result;
}
int NumTableFilesAtLevel(int level) {
std::string property;
EXPECT_TRUE(db_->GetProperty(
"rocksdb.num-files-at-level" + NumberToString(level), &property));
return atoi(property.c_str());
}
// Return spread of files per level
std::string FilesPerLevel() {
std::string result;
size_t last_non_zero_offset = 0;
for (int level = 0; level < db_->NumberLevels(); level++) {
int f = NumTableFilesAtLevel(level);
char buf[100];
snprintf(buf, sizeof(buf), "%s%d", (level ? "," : ""), f);
result += buf;
if (f > 0) {
last_non_zero_offset = result.size();
}
}
result.resize(last_non_zero_offset);
return result;
}
};
TEST_F(CuckooTableDBTest, Flush) {
// Try with empty DB first.
ASSERT_TRUE(dbfull() != nullptr);
ASSERT_EQ("NOT_FOUND", Get("key2"));
// Add some values to db.
Options options = CurrentOptions();
Reopen(&options);
ASSERT_OK(Put("key1", "v1"));
ASSERT_OK(Put("key2", "v2"));
ASSERT_OK(Put("key3", "v3"));
dbfull()->TEST_FlushMemTable();
TablePropertiesCollection ptc;
reinterpret_cast<DB*>(dbfull())->GetPropertiesOfAllTables(&ptc);
ASSERT_EQ(1U, ptc.size());
ASSERT_EQ(3U, ptc.begin()->second->num_entries);
ASSERT_EQ("1", FilesPerLevel());
ASSERT_EQ("v1", Get("key1"));
ASSERT_EQ("v2", Get("key2"));
ASSERT_EQ("v3", Get("key3"));
ASSERT_EQ("NOT_FOUND", Get("key4"));
// Now add more keys and flush.
ASSERT_OK(Put("key4", "v4"));
ASSERT_OK(Put("key5", "v5"));
ASSERT_OK(Put("key6", "v6"));
dbfull()->TEST_FlushMemTable();
reinterpret_cast<DB*>(dbfull())->GetPropertiesOfAllTables(&ptc);
ASSERT_EQ(2U, ptc.size());
auto row = ptc.begin();
ASSERT_EQ(3U, row->second->num_entries);
ASSERT_EQ(3U, (++row)->second->num_entries);
ASSERT_EQ("2", FilesPerLevel());
ASSERT_EQ("v1", Get("key1"));
ASSERT_EQ("v2", Get("key2"));
ASSERT_EQ("v3", Get("key3"));
ASSERT_EQ("v4", Get("key4"));
ASSERT_EQ("v5", Get("key5"));
ASSERT_EQ("v6", Get("key6"));
ASSERT_OK(Delete("key6"));
ASSERT_OK(Delete("key5"));
ASSERT_OK(Delete("key4"));
dbfull()->TEST_FlushMemTable();
reinterpret_cast<DB*>(dbfull())->GetPropertiesOfAllTables(&ptc);
ASSERT_EQ(3U, ptc.size());
row = ptc.begin();
ASSERT_EQ(3U, row->second->num_entries);
ASSERT_EQ(3U, (++row)->second->num_entries);
ASSERT_EQ(3U, (++row)->second->num_entries);
ASSERT_EQ("3", FilesPerLevel());
ASSERT_EQ("v1", Get("key1"));
ASSERT_EQ("v2", Get("key2"));
ASSERT_EQ("v3", Get("key3"));
ASSERT_EQ("NOT_FOUND", Get("key4"));
ASSERT_EQ("NOT_FOUND", Get("key5"));
ASSERT_EQ("NOT_FOUND", Get("key6"));
}
TEST_F(CuckooTableDBTest, FlushWithDuplicateKeys) {
Options options = CurrentOptions();
Reopen(&options);
ASSERT_OK(Put("key1", "v1"));
ASSERT_OK(Put("key2", "v2"));
ASSERT_OK(Put("key1", "v3")); // Duplicate
dbfull()->TEST_FlushMemTable();
TablePropertiesCollection ptc;
reinterpret_cast<DB*>(dbfull())->GetPropertiesOfAllTables(&ptc);
ASSERT_EQ(1U, ptc.size());
ASSERT_EQ(2U, ptc.begin()->second->num_entries);
ASSERT_EQ("1", FilesPerLevel());
ASSERT_EQ("v3", Get("key1"));
ASSERT_EQ("v2", Get("key2"));
}
namespace {
static std::string Key(int i) {
char buf[100];
snprintf(buf, sizeof(buf), "key_______%06d", i);
return std::string(buf);
}
static std::string Uint64Key(uint64_t i) {
std::string str;
str.resize(8);
memcpy(&str[0], static_cast<void*>(&i), 8);
return str;
}
} // namespace.
TEST_F(CuckooTableDBTest, Uint64Comparator) {
Options options = CurrentOptions();
options.comparator = test::Uint64Comparator();
DestroyAndReopen(&options);
ASSERT_OK(Put(Uint64Key(1), "v1"));
ASSERT_OK(Put(Uint64Key(2), "v2"));
ASSERT_OK(Put(Uint64Key(3), "v3"));
dbfull()->TEST_FlushMemTable();
ASSERT_EQ("v1", Get(Uint64Key(1)));
ASSERT_EQ("v2", Get(Uint64Key(2)));
ASSERT_EQ("v3", Get(Uint64Key(3)));
ASSERT_EQ("NOT_FOUND", Get(Uint64Key(4)));
// Add more keys.
ASSERT_OK(Delete(Uint64Key(2))); // Delete.
dbfull()->TEST_FlushMemTable();
ASSERT_OK(Put(Uint64Key(3), "v0")); // Update.
ASSERT_OK(Put(Uint64Key(4), "v4"));
dbfull()->TEST_FlushMemTable();
ASSERT_EQ("v1", Get(Uint64Key(1)));
ASSERT_EQ("NOT_FOUND", Get(Uint64Key(2)));
ASSERT_EQ("v0", Get(Uint64Key(3)));
ASSERT_EQ("v4", Get(Uint64Key(4)));
}
TEST_F(CuckooTableDBTest, CompactionIntoMultipleFiles) {
// Create a big L0 file and check it compacts into multiple files in L1.
Options options = CurrentOptions();
options.write_buffer_size = 270 << 10;
// Two SST files should be created, each containing 14 keys.
// Number of buckets will be 16. Total size ~156 KB.
options.target_file_size_base = 160 << 10;
Reopen(&options);
// Write 28 values, each 10016 B ~ 10KB
for (int idx = 0; idx < 28; ++idx) {
ASSERT_OK(Put(Key(idx), std::string(10000, 'a' + char(idx))));
}
dbfull()->TEST_WaitForFlushMemTable();
ASSERT_EQ("1", FilesPerLevel());
dbfull()->TEST_CompactRange(0, nullptr, nullptr, nullptr,
true /* disallow trivial move */);
ASSERT_EQ("0,2", FilesPerLevel());
for (int idx = 0; idx < 28; ++idx) {
ASSERT_EQ(std::string(10000, 'a' + char(idx)), Get(Key(idx)));
}
}
TEST_F(CuckooTableDBTest, SameKeyInsertedInTwoDifferentFilesAndCompacted) {
// Insert same key twice so that they go to different SST files. Then wait for
// compaction and check if the latest value is stored and old value removed.
Options options = CurrentOptions();
options.write_buffer_size = 100 << 10; // 100KB
options.level0_file_num_compaction_trigger = 2;
Reopen(&options);
// Write 11 values, each 10016 B
for (int idx = 0; idx < 11; ++idx) {
ASSERT_OK(Put(Key(idx), std::string(10000, 'a')));
}
dbfull()->TEST_WaitForFlushMemTable();
ASSERT_EQ("1", FilesPerLevel());
// Generate one more file in level-0, and should trigger level-0 compaction
for (int idx = 0; idx < 11; ++idx) {
ASSERT_OK(Put(Key(idx), std::string(10000, 'a' + char(idx))));
}
dbfull()->TEST_WaitForFlushMemTable();
dbfull()->TEST_CompactRange(0, nullptr, nullptr);
ASSERT_EQ("0,1", FilesPerLevel());
for (int idx = 0; idx < 11; ++idx) {
ASSERT_EQ(std::string(10000, 'a' + char(idx)), Get(Key(idx)));
}
}
TEST_F(CuckooTableDBTest, AdaptiveTable) {
Options options = CurrentOptions();
// Ensure options compatible with PlainTable
options.prefix_extractor.reset(NewCappedPrefixTransform(8));
// Write some keys using cuckoo table.
options.table_factory.reset(NewCuckooTableFactory());
Reopen(&options);
ASSERT_OK(Put("key1", "v1"));
ASSERT_OK(Put("key2", "v2"));
ASSERT_OK(Put("key3", "v3"));
dbfull()->TEST_FlushMemTable();
// Write some keys using plain table.
std::shared_ptr<TableFactory> block_based_factory(
NewBlockBasedTableFactory());
std::shared_ptr<TableFactory> plain_table_factory(
NewPlainTableFactory());
std::shared_ptr<TableFactory> cuckoo_table_factory(
NewCuckooTableFactory());
options.create_if_missing = false;
options.table_factory.reset(NewAdaptiveTableFactory(
plain_table_factory, block_based_factory, plain_table_factory,
cuckoo_table_factory));
Reopen(&options);
ASSERT_OK(Put("key4", "v4"));
ASSERT_OK(Put("key1", "v5"));
dbfull()->TEST_FlushMemTable();
// Write some keys using block based table.
options.table_factory.reset(NewAdaptiveTableFactory(
block_based_factory, block_based_factory, plain_table_factory,
cuckoo_table_factory));
Reopen(&options);
ASSERT_OK(Put("key5", "v6"));
ASSERT_OK(Put("key2", "v7"));
dbfull()->TEST_FlushMemTable();
ASSERT_EQ("v5", Get("key1"));
ASSERT_EQ("v7", Get("key2"));
ASSERT_EQ("v3", Get("key3"));
ASSERT_EQ("v4", Get("key4"));
ASSERT_EQ("v6", Get("key5"));
}
} // namespace ROCKSDB_NAMESPACE
int main(int argc, char** argv) {
if (ROCKSDB_NAMESPACE::port::kLittleEndian) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
} else {
fprintf(stderr, "SKIPPED as Cuckoo table doesn't support Big Endian\n");
return 0;
}
}
#else
#include <stdio.h>
int main(int /*argc*/, char** /*argv*/) {
fprintf(stderr, "SKIPPED as Cuckoo table is not supported in ROCKSDB_LITE\n");
return 0;
}
#endif // ROCKSDB_LITE