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91687d70ea
rocksdb/db/compact_files_test.cc
Andrew Kryczka 8ca433f912 Fix test race conditions with OnFlushCompleted() (#9617) 
Summary:
We often see flaky tests due to `DB::Flush()` or `DBImpl::TEST_WaitForFlushMemTable()` not waiting until event listeners complete. For example, https://github.com/facebook/rocksdb/issues/9084, https://github.com/facebook/rocksdb/issues/9400, https://github.com/facebook/rocksdb/issues/9528, plus two new ones this week: "EventListenerTest.OnSingleDBFlushTest" and "DBFlushTest.FireOnFlushCompletedAfterCommittedResult". I ran a `make check` with the below race condition-coercing patch and fixed  issues it found besides old BlobDB.

```
 diff --git a/db/db_impl/db_impl_compaction_flush.cc b/db/db_impl/db_impl_compaction_flush.cc
index 0e1864788..aaba68c4a 100644
 --- a/db/db_impl/db_impl_compaction_flush.cc
+++ b/db/db_impl/db_impl_compaction_flush.cc
@@ -861,6 +861,8 @@ void DBImpl::NotifyOnFlushCompleted(
        mutable_cf_options.level0_stop_writes_trigger);
   // release lock while notifying events
   mutex_.Unlock();
+  bg_cv_.SignalAll();
+  sleep(1);
   {
     for (auto& info : *flush_jobs_info) {
       info->triggered_writes_slowdown = triggered_writes_slowdown;
```

The reason I did not fix old BlobDB issues is because it appears to have a fundamental (non-test) issue. In particular, it uses an EventListener to keep track of the files. OnFlushCompleted() could be delayed until even after a compaction involving that flushed file completes, causing the compaction to unexpectedly delete an untracked file.

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9617

Test Plan: `make check` including the race condition coercing patch

Reviewed By: hx235

Differential Revision: D34384022

Pulled By: ajkr

fbshipit-source-id: 2652ded39b415277c5d6a628414345223930514e
2022-02-22 12:23:00 -08:00

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// 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 <mutex>
#include <string>
#include <thread>
#include <vector>
#include "db/db_impl/db_impl.h"
#include "port/port.h"
#include "rocksdb/db.h"
#include "rocksdb/env.h"
#include "test_util/sync_point.h"
#include "test_util/testharness.h"
#include "util/cast_util.h"
#include "util/string_util.h"
namespace ROCKSDB_NAMESPACE {
class CompactFilesTest : public testing::Test {
public:
CompactFilesTest() {
env_ = Env::Default();
db_name_ = test::PerThreadDBPath("compact_files_test");
}
std::string db_name_;
Env* env_;
};
// A class which remembers the name of each flushed file.
class FlushedFileCollector : public EventListener {
public:
FlushedFileCollector() {}
~FlushedFileCollector() override {}
void OnFlushCompleted(DB* /*db*/, const FlushJobInfo& info) override {
std::lock_guard<std::mutex> lock(mutex_);
flushed_files_.push_back(info.file_path);
}
std::vector<std::string> GetFlushedFiles() {
std::lock_guard<std::mutex> lock(mutex_);
std::vector<std::string> result;
for (auto fname : flushed_files_) {
result.push_back(fname);
}
return result;
}
void ClearFlushedFiles() {
std::lock_guard<std::mutex> lock(mutex_);
flushed_files_.clear();
}
private:
std::vector<std::string> flushed_files_;
std::mutex mutex_;
};
TEST_F(CompactFilesTest, L0ConflictsFiles) {
Options options;
// to trigger compaction more easily
const int kWriteBufferSize = 10000;
const int kLevel0Trigger = 2;
options.create_if_missing = true;
options.compaction_style = kCompactionStyleLevel;
// Small slowdown and stop trigger for experimental purpose.
options.level0_slowdown_writes_trigger = 20;
options.level0_stop_writes_trigger = 20;
options.level0_stop_writes_trigger = 20;
options.write_buffer_size = kWriteBufferSize;
options.level0_file_num_compaction_trigger = kLevel0Trigger;
options.compression = kNoCompression;
DB* db = nullptr;
DestroyDB(db_name_, options);
Status s = DB::Open(options, db_name_, &db);
assert(s.ok());
assert(db);
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->LoadDependency({
{"CompactFilesImpl:0", "BackgroundCallCompaction:0"},
{"BackgroundCallCompaction:1", "CompactFilesImpl:1"},
});
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
// create couple files
// Background compaction starts and waits in BackgroundCallCompaction:0
for (int i = 0; i < kLevel0Trigger * 4; ++i) {
ASSERT_OK(db->Put(WriteOptions(), ToString(i), ""));
ASSERT_OK(db->Put(WriteOptions(), ToString(100 - i), ""));
ASSERT_OK(db->Flush(FlushOptions()));
}
ROCKSDB_NAMESPACE::ColumnFamilyMetaData meta;
db->GetColumnFamilyMetaData(&meta);
std::string file1;
for (auto& file : meta.levels[0].files) {
ASSERT_EQ(0, meta.levels[0].level);
if (file1 == "") {
file1 = file.db_path + "/" + file.name;
} else {
std::string file2 = file.db_path + "/" + file.name;
// Another thread starts a compact files and creates an L0 compaction
// The background compaction then notices that there is an L0 compaction
// already in progress and doesn't do an L0 compaction
// Once the background compaction finishes, the compact files finishes
ASSERT_OK(db->CompactFiles(ROCKSDB_NAMESPACE::CompactionOptions(),
{file1, file2}, 0));
break;
}
}
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->DisableProcessing();
delete db;
}
TEST_F(CompactFilesTest, MultipleLevel) {
Options options;
options.create_if_missing = true;
options.level_compaction_dynamic_level_bytes = true;
options.num_levels = 6;
// Add listener
FlushedFileCollector* collector = new FlushedFileCollector();
options.listeners.emplace_back(collector);
DB* db = nullptr;
DestroyDB(db_name_, options);
Status s = DB::Open(options, db_name_, &db);
ASSERT_OK(s);
ASSERT_NE(db, nullptr);
// create couple files in L0, L3, L4 and L5
for (int i = 5; i > 2; --i) {
collector->ClearFlushedFiles();
ASSERT_OK(db->Put(WriteOptions(), ToString(i), ""));
ASSERT_OK(db->Flush(FlushOptions()));
// Ensure background work is fully finished including listener callbacks
// before accessing listener state.
ASSERT_OK(static_cast_with_check<DBImpl>(db)->TEST_WaitForBackgroundWork());
auto l0_files = collector->GetFlushedFiles();
ASSERT_OK(db->CompactFiles(CompactionOptions(), l0_files, i));
std::string prop;
ASSERT_TRUE(
db->GetProperty("rocksdb.num-files-at-level" + ToString(i), &prop));
ASSERT_EQ("1", prop);
}
ASSERT_OK(db->Put(WriteOptions(), ToString(0), ""));
ASSERT_OK(db->Flush(FlushOptions()));
ColumnFamilyMetaData meta;
db->GetColumnFamilyMetaData(&meta);
// Compact files except the file in L3
std::vector<std::string> files;
for (int i = 0; i < 6; ++i) {
if (i == 3) continue;
for (auto& file : meta.levels[i].files) {
files.push_back(file.db_path + "/" + file.name);
}
}
SyncPoint::GetInstance()->LoadDependency({
{"CompactionJob::Run():Start", "CompactFilesTest.MultipleLevel:0"},
{"CompactFilesTest.MultipleLevel:1", "CompactFilesImpl:3"},
});
SyncPoint::GetInstance()->EnableProcessing();
std::thread thread([&] {
TEST_SYNC_POINT("CompactFilesTest.MultipleLevel:0");
ASSERT_OK(db->Put(WriteOptions(), "bar", "v2"));
ASSERT_OK(db->Put(WriteOptions(), "foo", "v2"));
ASSERT_OK(db->Flush(FlushOptions()));
TEST_SYNC_POINT("CompactFilesTest.MultipleLevel:1");
});
// Compaction cannot move up the data to higher level
// here we have input file from level 5, so the output level has to be >= 5
for (int invalid_output_level = 0; invalid_output_level < 5;
invalid_output_level++) {
s = db->CompactFiles(CompactionOptions(), files, invalid_output_level);
std::cout << s.ToString() << std::endl;
ASSERT_TRUE(s.IsInvalidArgument());
}
ASSERT_OK(db->CompactFiles(CompactionOptions(), files, 5));
SyncPoint::GetInstance()->DisableProcessing();
thread.join();
delete db;
}
TEST_F(CompactFilesTest, ObsoleteFiles) {
Options options;
// to trigger compaction more easily
const int kWriteBufferSize = 65536;
options.create_if_missing = true;
// Disable RocksDB background compaction.
options.compaction_style = kCompactionStyleNone;
options.level0_slowdown_writes_trigger = (1 << 30);
options.level0_stop_writes_trigger = (1 << 30);
options.write_buffer_size = kWriteBufferSize;
options.max_write_buffer_number = 2;
options.compression = kNoCompression;
// Add listener
FlushedFileCollector* collector = new FlushedFileCollector();
options.listeners.emplace_back(collector);
DB* db = nullptr;
DestroyDB(db_name_, options);
Status s = DB::Open(options, db_name_, &db);
ASSERT_OK(s);
ASSERT_NE(db, nullptr);
// create couple files
for (int i = 1000; i < 2000; ++i) {
ASSERT_OK(db->Put(WriteOptions(), ToString(i),
std::string(kWriteBufferSize / 10, 'a' + (i % 26))));
}
auto l0_files = collector->GetFlushedFiles();
ASSERT_OK(db->CompactFiles(CompactionOptions(), l0_files, 1));
ASSERT_OK(static_cast_with_check<DBImpl>(db)->TEST_WaitForCompact());
// verify all compaction input files are deleted
for (auto fname : l0_files) {
ASSERT_EQ(Status::NotFound(), env_->FileExists(fname));
}
delete db;
}
TEST_F(CompactFilesTest, NotCutOutputOnLevel0) {
Options options;
options.create_if_missing = true;
// Disable RocksDB background compaction.
options.compaction_style = kCompactionStyleNone;
options.level0_slowdown_writes_trigger = 1000;
options.level0_stop_writes_trigger = 1000;
options.write_buffer_size = 65536;
options.max_write_buffer_number = 2;
options.compression = kNoCompression;
options.max_compaction_bytes = 5000;
// Add listener
FlushedFileCollector* collector = new FlushedFileCollector();
options.listeners.emplace_back(collector);
DB* db = nullptr;
DestroyDB(db_name_, options);
Status s = DB::Open(options, db_name_, &db);
assert(s.ok());
assert(db);
// create couple files
for (int i = 0; i < 500; ++i) {
ASSERT_OK(db->Put(WriteOptions(), ToString(i),
std::string(1000, 'a' + (i % 26))));
}
ASSERT_OK(static_cast_with_check<DBImpl>(db)->TEST_WaitForFlushMemTable());
auto l0_files_1 = collector->GetFlushedFiles();
collector->ClearFlushedFiles();
for (int i = 0; i < 500; ++i) {
ASSERT_OK(db->Put(WriteOptions(), ToString(i),
std::string(1000, 'a' + (i % 26))));
}
ASSERT_OK(static_cast_with_check<DBImpl>(db)->TEST_WaitForFlushMemTable());
auto l0_files_2 = collector->GetFlushedFiles();
ASSERT_OK(db->CompactFiles(CompactionOptions(), l0_files_1, 0));
ASSERT_OK(db->CompactFiles(CompactionOptions(), l0_files_2, 0));
// no assertion failure
delete db;
}
TEST_F(CompactFilesTest, CapturingPendingFiles) {
Options options;
options.create_if_missing = true;
// Disable RocksDB background compaction.
options.compaction_style = kCompactionStyleNone;
// Always do full scans for obsolete files (needed to reproduce the issue).
options.delete_obsolete_files_period_micros = 0;
// Add listener.
FlushedFileCollector* collector = new FlushedFileCollector();
options.listeners.emplace_back(collector);
DB* db = nullptr;
DestroyDB(db_name_, options);
Status s = DB::Open(options, db_name_, &db);
ASSERT_OK(s);
assert(db);
// Create 5 files.
for (int i = 0; i < 5; ++i) {
ASSERT_OK(db->Put(WriteOptions(), "key" + ToString(i), "value"));
ASSERT_OK(db->Flush(FlushOptions()));
}
// Ensure background work is fully finished including listener callbacks
// before accessing listener state.
ASSERT_OK(static_cast_with_check<DBImpl>(db)->TEST_WaitForBackgroundWork());
auto l0_files = collector->GetFlushedFiles();
EXPECT_EQ(5, l0_files.size());
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->LoadDependency({
{"CompactFilesImpl:2", "CompactFilesTest.CapturingPendingFiles:0"},
{"CompactFilesTest.CapturingPendingFiles:1", "CompactFilesImpl:3"},
});
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
// Start compacting files.
ROCKSDB_NAMESPACE::port::Thread compaction_thread(
[&] { EXPECT_OK(db->CompactFiles(CompactionOptions(), l0_files, 1)); });
// In the meantime flush another file.
TEST_SYNC_POINT("CompactFilesTest.CapturingPendingFiles:0");
ASSERT_OK(db->Put(WriteOptions(), "key5", "value"));
ASSERT_OK(db->Flush(FlushOptions()));
TEST_SYNC_POINT("CompactFilesTest.CapturingPendingFiles:1");
compaction_thread.join();
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->DisableProcessing();
delete db;
// Make sure we can reopen the DB.
s = DB::Open(options, db_name_, &db);
ASSERT_OK(s);
assert(db);
delete db;
}
TEST_F(CompactFilesTest, CompactionFilterWithGetSv) {
class FilterWithGet : public CompactionFilter {
public:
bool Filter(int /*level*/, const Slice& /*key*/, const Slice& /*value*/,
std::string* /*new_value*/,
bool* /*value_changed*/) const override {
if (db_ == nullptr) {
return true;
}
std::string res;
db_->Get(ReadOptions(), "", &res);
return true;
}
void SetDB(DB* db) {
db_ = db;
}
const char* Name() const override { return "FilterWithGet"; }
private:
DB* db_;
};
std::shared_ptr<FilterWithGet> cf(new FilterWithGet());
Options options;
options.create_if_missing = true;
options.compaction_filter = cf.get();
DB* db = nullptr;
DestroyDB(db_name_, options);
Status s = DB::Open(options, db_name_, &db);
ASSERT_OK(s);
cf->SetDB(db);
// Write one L0 file
ASSERT_OK(db->Put(WriteOptions(), "K1", "V1"));
ASSERT_OK(db->Flush(FlushOptions()));
// Compact all L0 files using CompactFiles
ROCKSDB_NAMESPACE::ColumnFamilyMetaData meta;
db->GetColumnFamilyMetaData(&meta);
for (auto& file : meta.levels[0].files) {
std::string fname = file.db_path + "/" + file.name;
ASSERT_OK(
db->CompactFiles(ROCKSDB_NAMESPACE::CompactionOptions(), {fname}, 0));
}
delete db;
}
TEST_F(CompactFilesTest, SentinelCompressionType) {
if (!Zlib_Supported()) {
fprintf(stderr, "zlib compression not supported, skip this test\n");
return;
}
if (!Snappy_Supported()) {
fprintf(stderr, "snappy compression not supported, skip this test\n");
return;
}
// Check that passing `CompressionType::kDisableCompressionOption` to
// `CompactFiles` causes it to use the column family compression options.
for (auto compaction_style :
{CompactionStyle::kCompactionStyleLevel,
CompactionStyle::kCompactionStyleUniversal,
CompactionStyle::kCompactionStyleNone}) {
DestroyDB(db_name_, Options());
Options options;
options.compaction_style = compaction_style;
// L0: Snappy, L1: ZSTD, L2: Snappy
options.compression_per_level = {CompressionType::kSnappyCompression,
CompressionType::kZlibCompression,
CompressionType::kSnappyCompression};
options.create_if_missing = true;
FlushedFileCollector* collector = new FlushedFileCollector();
options.listeners.emplace_back(collector);
DB* db = nullptr;
ASSERT_OK(DB::Open(options, db_name_, &db));
ASSERT_OK(db->Put(WriteOptions(), "key", "val"));
ASSERT_OK(db->Flush(FlushOptions()));
// Ensure background work is fully finished including listener callbacks
// before accessing listener state.
ASSERT_OK(static_cast_with_check<DBImpl>(db)->TEST_WaitForBackgroundWork());
auto l0_files = collector->GetFlushedFiles();
ASSERT_EQ(1, l0_files.size());
// L0->L1 compaction, so output should be ZSTD-compressed
CompactionOptions compaction_opts;
compaction_opts.compression = CompressionType::kDisableCompressionOption;
ASSERT_OK(db->CompactFiles(compaction_opts, l0_files, 1));
ROCKSDB_NAMESPACE::TablePropertiesCollection all_tables_props;
ASSERT_OK(db->GetPropertiesOfAllTables(&all_tables_props));
for (const auto& name_and_table_props : all_tables_props) {
ASSERT_EQ(CompressionTypeToString(CompressionType::kZlibCompression),
name_and_table_props.second->compression_name);
}
delete db;
}
}
TEST_F(CompactFilesTest, GetCompactionJobInfo) {
Options options;
options.create_if_missing = true;
// Disable RocksDB background compaction.
options.compaction_style = kCompactionStyleNone;
options.level0_slowdown_writes_trigger = 1000;
options.level0_stop_writes_trigger = 1000;
options.write_buffer_size = 65536;
options.max_write_buffer_number = 2;
options.compression = kNoCompression;
options.max_compaction_bytes = 5000;
// Add listener
FlushedFileCollector* collector = new FlushedFileCollector();
options.listeners.emplace_back(collector);
DB* db = nullptr;
DestroyDB(db_name_, options);
Status s = DB::Open(options, db_name_, &db);
ASSERT_OK(s);
assert(db);
// create couple files
for (int i = 0; i < 500; ++i) {
ASSERT_OK(db->Put(WriteOptions(), ToString(i),
std::string(1000, 'a' + (i % 26))));
}
ASSERT_OK(static_cast_with_check<DBImpl>(db)->TEST_WaitForFlushMemTable());
auto l0_files_1 = collector->GetFlushedFiles();
CompactionOptions co;
co.compression = CompressionType::kLZ4Compression;
CompactionJobInfo compaction_job_info{};
ASSERT_OK(
db->CompactFiles(co, l0_files_1, 0, -1, nullptr, &compaction_job_info));
ASSERT_EQ(compaction_job_info.base_input_level, 0);
ASSERT_EQ(compaction_job_info.cf_id, db->DefaultColumnFamily()->GetID());
ASSERT_EQ(compaction_job_info.cf_name, db->DefaultColumnFamily()->GetName());
ASSERT_EQ(compaction_job_info.compaction_reason,
CompactionReason::kManualCompaction);
ASSERT_EQ(compaction_job_info.compression, CompressionType::kLZ4Compression);
ASSERT_EQ(compaction_job_info.output_level, 0);
ASSERT_OK(compaction_job_info.status);
// no assertion failure
delete db;
}
} // namespace ROCKSDB_NAMESPACE
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 DBImpl::CompactFiles is not supported in ROCKSDB_LITE\n");
return 0;
}
#endif // !ROCKSDB_LITE
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