Revision 499ebb3ab5ea4207950fc95acf102b8f58add1c5 authored by Maysam Yabandeh on 24 June 2017, 21:06:43 UTC, committed by Facebook Github Bot on 24 June 2017, 21:11:29 UTC
Summary: Throughput: 46k tps in our sysbench settings (filling the details later) The idea is to have the simplest change that gives us a reasonable boost in 2PC throughput. Major design changes: 1. The WAL file internal buffer is not flushed after each write. Instead it is flushed before critical operations (WAL copy via fs) or when FlushWAL is called by MySQL. Flushing the WAL buffer is also protected via mutex_. 2. Use two sequence numbers: last seq, and last seq for write. Last seq is the last visible sequence number for reads. Last seq for write is the next sequence number that should be used to write to WAL/memtable. This allows to have a memtable write be in parallel to WAL writes. 3. BatchGroup is not used for writes. This means that we can have parallel writers which changes a major assumption in the code base. To accommodate for that i) allow only 1 WriteImpl that intends to write to memtable via mem_mutex_--which is fine since in 2PC almost all of the memtable writes come via group commit phase which is serial anyway, ii) make all the parts in the code base that assumed to be the only writer (via EnterUnbatched) to also acquire mem_mutex_, iii) stat updates are protected via a stat_mutex_. Note: the first commit has the approach figured out but is not clean. Submitting the PR anyway to get the early feedback on the approach. If we are ok with the approach I will go ahead with this updates: 0) Rebase with Yi's pipelining changes 1) Currently batching is disabled by default to make sure that it will be consistent with all unit tests. Will make this optional via a config. 2) A couple of unit tests are disabled. They need to be updated with the serial commit of 2PC taken into account. 3) Replacing BatchGroup with mem_mutex_ got a bit ugly as it requires releasing mutex_ beforehand (the same way EnterUnbatched does). This needs to be cleaned up. Closes https://github.com/facebook/rocksdb/pull/2345 Differential Revision: D5210732 Pulled By: maysamyabandeh fbshipit-source-id: 78653bd95a35cd1e831e555e0e57bdfd695355a4
1 parent 0ac4afb
compaction_iterator_test.cc
// Copyright (c) 2011-present, 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.
// This source code is also licensed under the GPLv2 license found in the
// COPYING file in the root directory of this source tree.
#include "db/compaction_iterator.h"
#include <string>
#include <vector>
#include "port/port.h"
#include "util/testharness.h"
#include "util/testutil.h"
namespace rocksdb {
// Expects no merging attempts.
class NoMergingMergeOp : public MergeOperator {
public:
bool FullMergeV2(const MergeOperationInput& merge_in,
MergeOperationOutput* merge_out) const override {
ADD_FAILURE();
return false;
}
bool PartialMergeMulti(const Slice& key,
const std::deque<Slice>& operand_list,
std::string* new_value,
Logger* logger) const override {
ADD_FAILURE();
return false;
}
const char* Name() const override {
return "CompactionIteratorTest NoMergingMergeOp";
}
};
// Compaction filter that gets stuck when it sees a particular key,
// then gets unstuck when told to.
// Always returns Decition::kRemove.
class StallingFilter : public CompactionFilter {
public:
virtual Decision FilterV2(int level, const Slice& key, ValueType t,
const Slice& existing_value, std::string* new_value,
std::string* skip_until) const override {
int k = std::atoi(key.ToString().c_str());
last_seen.store(k);
while (k >= stall_at.load()) {
std::this_thread::yield();
}
return Decision::kRemove;
}
const char* Name() const override {
return "CompactionIteratorTest StallingFilter";
}
// Wait until the filter sees a key >= k and stalls at that key.
// If `exact`, asserts that the seen key is equal to k.
void WaitForStall(int k, bool exact = true) {
stall_at.store(k);
while (last_seen.load() < k) {
std::this_thread::yield();
}
if (exact) {
EXPECT_EQ(k, last_seen.load());
}
}
// Filter will stall on key >= stall_at. Advance stall_at to unstall.
mutable std::atomic<int> stall_at{0};
// Last key the filter was called with.
mutable std::atomic<int> last_seen{0};
};
class LoggingForwardVectorIterator : public InternalIterator {
public:
struct Action {
enum class Type {
SEEK_TO_FIRST,
SEEK,
NEXT,
};
Type type;
std::string arg;
explicit Action(Type _type, std::string _arg = "")
: type(_type), arg(_arg) {}
bool operator==(const Action& rhs) const {
return std::tie(type, arg) == std::tie(rhs.type, rhs.arg);
}
};
LoggingForwardVectorIterator(const std::vector<std::string>& keys,
const std::vector<std::string>& values)
: keys_(keys), values_(values), current_(keys.size()) {
assert(keys_.size() == values_.size());
}
virtual bool Valid() const override { return current_ < keys_.size(); }
virtual void SeekToFirst() override {
log.emplace_back(Action::Type::SEEK_TO_FIRST);
current_ = 0;
}
virtual void SeekToLast() override { assert(false); }
virtual void Seek(const Slice& target) override {
log.emplace_back(Action::Type::SEEK, target.ToString());
current_ = std::lower_bound(keys_.begin(), keys_.end(), target.ToString()) -
keys_.begin();
}
virtual void SeekForPrev(const Slice& target) override { assert(false); }
virtual void Next() override {
assert(Valid());
log.emplace_back(Action::Type::NEXT);
current_++;
}
virtual void Prev() override { assert(false); }
virtual Slice key() const override {
assert(Valid());
return Slice(keys_[current_]);
}
virtual Slice value() const override {
assert(Valid());
return Slice(values_[current_]);
}
virtual Status status() const override { return Status::OK(); }
std::vector<Action> log;
private:
std::vector<std::string> keys_;
std::vector<std::string> values_;
size_t current_;
};
class FakeCompaction : public CompactionIterator::CompactionProxy {
public:
FakeCompaction() = default;
virtual int level(size_t compaction_input_level) const { return 0; }
virtual bool KeyNotExistsBeyondOutputLevel(
const Slice& user_key, std::vector<size_t>* level_ptrs) const {
return key_not_exists_beyond_output_level;
}
virtual bool bottommost_level() const { return false; }
virtual int number_levels() const { return 1; }
virtual Slice GetLargestUserKey() const {
return "\xff\xff\xff\xff\xff\xff\xff\xff\xff";
}
virtual bool allow_ingest_behind() const { return false; }
bool key_not_exists_beyond_output_level = false;
};
class CompactionIteratorTest : public testing::Test {
public:
CompactionIteratorTest()
: cmp_(BytewiseComparator()), icmp_(cmp_), snapshots_({}) {}
void InitIterators(const std::vector<std::string>& ks,
const std::vector<std::string>& vs,
const std::vector<std::string>& range_del_ks,
const std::vector<std::string>& range_del_vs,
SequenceNumber last_sequence,
MergeOperator* merge_op = nullptr,
CompactionFilter* filter = nullptr) {
std::unique_ptr<InternalIterator> range_del_iter(
new test::VectorIterator(range_del_ks, range_del_vs));
range_del_agg_.reset(new RangeDelAggregator(icmp_, snapshots_));
ASSERT_OK(range_del_agg_->AddTombstones(std::move(range_del_iter)));
std::unique_ptr<CompactionIterator::CompactionProxy> compaction;
if (filter) {
compaction_proxy_ = new FakeCompaction();
compaction.reset(compaction_proxy_);
}
merge_helper_.reset(new MergeHelper(Env::Default(), cmp_, merge_op, filter,
nullptr, false, 0, 0, nullptr,
&shutting_down_));
iter_.reset(new LoggingForwardVectorIterator(ks, vs));
iter_->SeekToFirst();
c_iter_.reset(new CompactionIterator(
iter_.get(), cmp_, merge_helper_.get(), last_sequence, &snapshots_,
kMaxSequenceNumber, Env::Default(), false, range_del_agg_.get(),
std::move(compaction), filter, nullptr, &shutting_down_));
}
void AddSnapshot(SequenceNumber snapshot) { snapshots_.push_back(snapshot); }
const Comparator* cmp_;
const InternalKeyComparator icmp_;
std::vector<SequenceNumber> snapshots_;
std::unique_ptr<MergeHelper> merge_helper_;
std::unique_ptr<LoggingForwardVectorIterator> iter_;
std::unique_ptr<CompactionIterator> c_iter_;
std::unique_ptr<RangeDelAggregator> range_del_agg_;
std::atomic<bool> shutting_down_{false};
FakeCompaction* compaction_proxy_;
};
// It is possible that the output of the compaction iterator is empty even if
// the input is not.
TEST_F(CompactionIteratorTest, EmptyResult) {
InitIterators({test::KeyStr("a", 5, kTypeSingleDeletion),
test::KeyStr("a", 3, kTypeValue)},
{"", "val"}, {}, {}, 5);
c_iter_->SeekToFirst();
ASSERT_FALSE(c_iter_->Valid());
}
// If there is a corruption after a single deletion, the corrupted key should
// be preserved.
TEST_F(CompactionIteratorTest, CorruptionAfterSingleDeletion) {
InitIterators({test::KeyStr("a", 5, kTypeSingleDeletion),
test::KeyStr("a", 3, kTypeValue, true),
test::KeyStr("b", 10, kTypeValue)},
{"", "val", "val2"}, {}, {}, 10);
c_iter_->SeekToFirst();
ASSERT_TRUE(c_iter_->Valid());
ASSERT_EQ(test::KeyStr("a", 5, kTypeSingleDeletion),
c_iter_->key().ToString());
c_iter_->Next();
ASSERT_TRUE(c_iter_->Valid());
ASSERT_EQ(test::KeyStr("a", 3, kTypeValue, true), c_iter_->key().ToString());
c_iter_->Next();
ASSERT_TRUE(c_iter_->Valid());
ASSERT_EQ(test::KeyStr("b", 10, kTypeValue), c_iter_->key().ToString());
c_iter_->Next();
ASSERT_FALSE(c_iter_->Valid());
}
TEST_F(CompactionIteratorTest, SimpleRangeDeletion) {
InitIterators({test::KeyStr("morning", 5, kTypeValue),
test::KeyStr("morning", 2, kTypeValue),
test::KeyStr("night", 3, kTypeValue)},
{"zao", "zao", "wan"},
{test::KeyStr("ma", 4, kTypeRangeDeletion)}, {"mz"}, 5);
c_iter_->SeekToFirst();
ASSERT_TRUE(c_iter_->Valid());
ASSERT_EQ(test::KeyStr("morning", 5, kTypeValue), c_iter_->key().ToString());
c_iter_->Next();
ASSERT_TRUE(c_iter_->Valid());
ASSERT_EQ(test::KeyStr("night", 3, kTypeValue), c_iter_->key().ToString());
c_iter_->Next();
ASSERT_FALSE(c_iter_->Valid());
}
TEST_F(CompactionIteratorTest, RangeDeletionWithSnapshots) {
AddSnapshot(10);
std::vector<std::string> ks1;
ks1.push_back(test::KeyStr("ma", 28, kTypeRangeDeletion));
std::vector<std::string> vs1{"mz"};
std::vector<std::string> ks2{test::KeyStr("morning", 15, kTypeValue),
test::KeyStr("morning", 5, kTypeValue),
test::KeyStr("night", 40, kTypeValue),
test::KeyStr("night", 20, kTypeValue)};
std::vector<std::string> vs2{"zao 15", "zao 5", "wan 40", "wan 20"};
InitIterators(ks2, vs2, ks1, vs1, 40);
c_iter_->SeekToFirst();
ASSERT_TRUE(c_iter_->Valid());
ASSERT_EQ(test::KeyStr("morning", 5, kTypeValue), c_iter_->key().ToString());
c_iter_->Next();
ASSERT_TRUE(c_iter_->Valid());
ASSERT_EQ(test::KeyStr("night", 40, kTypeValue), c_iter_->key().ToString());
c_iter_->Next();
ASSERT_FALSE(c_iter_->Valid());
}
TEST_F(CompactionIteratorTest, CompactionFilterSkipUntil) {
class Filter : public CompactionFilter {
virtual Decision FilterV2(int level, const Slice& key, ValueType t,
const Slice& existing_value,
std::string* new_value,
std::string* skip_until) const override {
std::string k = key.ToString();
std::string v = existing_value.ToString();
// See InitIterators() call below for the sequence of keys and their
// filtering decisions. Here we closely assert that compaction filter is
// called with the expected keys and only them, and with the right values.
if (k == "a") {
EXPECT_EQ(ValueType::kValue, t);
EXPECT_EQ("av50", v);
return Decision::kKeep;
}
if (k == "b") {
EXPECT_EQ(ValueType::kValue, t);
EXPECT_EQ("bv60", v);
*skip_until = "d+";
return Decision::kRemoveAndSkipUntil;
}
if (k == "e") {
EXPECT_EQ(ValueType::kMergeOperand, t);
EXPECT_EQ("em71", v);
return Decision::kKeep;
}
if (k == "f") {
if (v == "fm65") {
EXPECT_EQ(ValueType::kMergeOperand, t);
*skip_until = "f";
} else {
EXPECT_EQ("fm30", v);
EXPECT_EQ(ValueType::kMergeOperand, t);
*skip_until = "g+";
}
return Decision::kRemoveAndSkipUntil;
}
if (k == "h") {
EXPECT_EQ(ValueType::kValue, t);
EXPECT_EQ("hv91", v);
return Decision::kKeep;
}
if (k == "i") {
EXPECT_EQ(ValueType::kMergeOperand, t);
EXPECT_EQ("im95", v);
*skip_until = "z";
return Decision::kRemoveAndSkipUntil;
}
ADD_FAILURE();
return Decision::kKeep;
}
const char* Name() const override {
return "CompactionIteratorTest.CompactionFilterSkipUntil::Filter";
}
};
NoMergingMergeOp merge_op;
Filter filter;
InitIterators(
{test::KeyStr("a", 50, kTypeValue), // keep
test::KeyStr("a", 45, kTypeMerge),
test::KeyStr("b", 60, kTypeValue), // skip to "d+"
test::KeyStr("b", 40, kTypeValue), test::KeyStr("c", 35, kTypeValue),
test::KeyStr("d", 70, kTypeMerge),
test::KeyStr("e", 71, kTypeMerge), // keep
test::KeyStr("f", 65, kTypeMerge), // skip to "f", aka keep
test::KeyStr("f", 30, kTypeMerge), // skip to "g+"
test::KeyStr("f", 25, kTypeValue), test::KeyStr("g", 90, kTypeValue),
test::KeyStr("h", 91, kTypeValue), // keep
test::KeyStr("i", 95, kTypeMerge), // skip to "z"
test::KeyStr("j", 99, kTypeValue)},
{"av50", "am45", "bv60", "bv40", "cv35", "dm70", "em71", "fm65", "fm30",
"fv25", "gv90", "hv91", "im95", "jv99"},
{}, {}, kMaxSequenceNumber, &merge_op, &filter);
// Compaction should output just "a", "e" and "h" keys.
c_iter_->SeekToFirst();
ASSERT_TRUE(c_iter_->Valid());
ASSERT_EQ(test::KeyStr("a", 50, kTypeValue), c_iter_->key().ToString());
ASSERT_EQ("av50", c_iter_->value().ToString());
c_iter_->Next();
ASSERT_TRUE(c_iter_->Valid());
ASSERT_EQ(test::KeyStr("e", 71, kTypeMerge), c_iter_->key().ToString());
ASSERT_EQ("em71", c_iter_->value().ToString());
c_iter_->Next();
ASSERT_TRUE(c_iter_->Valid());
ASSERT_EQ(test::KeyStr("h", 91, kTypeValue), c_iter_->key().ToString());
ASSERT_EQ("hv91", c_iter_->value().ToString());
c_iter_->Next();
ASSERT_FALSE(c_iter_->Valid());
// Check that the compaction iterator did the correct sequence of calls on
// the underlying iterator.
using A = LoggingForwardVectorIterator::Action;
using T = A::Type;
std::vector<A> expected_actions = {
A(T::SEEK_TO_FIRST),
A(T::NEXT),
A(T::NEXT),
A(T::SEEK, test::KeyStr("d+", kMaxSequenceNumber, kValueTypeForSeek)),
A(T::NEXT),
A(T::NEXT),
A(T::SEEK, test::KeyStr("g+", kMaxSequenceNumber, kValueTypeForSeek)),
A(T::NEXT),
A(T::SEEK, test::KeyStr("z", kMaxSequenceNumber, kValueTypeForSeek))};
ASSERT_EQ(expected_actions, iter_->log);
}
TEST_F(CompactionIteratorTest, ShuttingDownInFilter) {
NoMergingMergeOp merge_op;
StallingFilter filter;
InitIterators(
{test::KeyStr("1", 1, kTypeValue), test::KeyStr("2", 2, kTypeValue),
test::KeyStr("3", 3, kTypeValue), test::KeyStr("4", 4, kTypeValue)},
{"v1", "v2", "v3", "v4"}, {}, {}, kMaxSequenceNumber, &merge_op, &filter);
// Don't leave tombstones (kTypeDeletion) for filtered keys.
compaction_proxy_->key_not_exists_beyond_output_level = true;
std::atomic<bool> seek_done{false};
rocksdb::port::Thread compaction_thread([&] {
c_iter_->SeekToFirst();
EXPECT_FALSE(c_iter_->Valid());
EXPECT_TRUE(c_iter_->status().IsShutdownInProgress());
seek_done.store(true);
});
// Let key 1 through.
filter.WaitForStall(1);
// Shutdown during compaction filter call for key 2.
filter.WaitForStall(2);
shutting_down_.store(true);
EXPECT_FALSE(seek_done.load());
// Unstall filter and wait for SeekToFirst() to return.
filter.stall_at.store(3);
compaction_thread.join();
assert(seek_done.load());
// Check that filter was never called again.
EXPECT_EQ(2, filter.last_seen.load());
}
// Same as ShuttingDownInFilter, but shutdown happens during filter call for
// a merge operand, not for a value.
TEST_F(CompactionIteratorTest, ShuttingDownInMerge) {
NoMergingMergeOp merge_op;
StallingFilter filter;
InitIterators(
{test::KeyStr("1", 1, kTypeValue), test::KeyStr("2", 2, kTypeMerge),
test::KeyStr("3", 3, kTypeMerge), test::KeyStr("4", 4, kTypeValue)},
{"v1", "v2", "v3", "v4"}, {}, {}, kMaxSequenceNumber, &merge_op, &filter);
compaction_proxy_->key_not_exists_beyond_output_level = true;
std::atomic<bool> seek_done{false};
rocksdb::port::Thread compaction_thread([&] {
c_iter_->SeekToFirst();
ASSERT_FALSE(c_iter_->Valid());
ASSERT_TRUE(c_iter_->status().IsShutdownInProgress());
seek_done.store(true);
});
// Let key 1 through.
filter.WaitForStall(1);
// Shutdown during compaction filter call for key 2.
filter.WaitForStall(2);
shutting_down_.store(true);
EXPECT_FALSE(seek_done.load());
// Unstall filter and wait for SeekToFirst() to return.
filter.stall_at.store(3);
compaction_thread.join();
assert(seek_done.load());
// Check that filter was never called again.
EXPECT_EQ(2, filter.last_seen.load());
}
} // namespace rocksdb
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
Computing file changes ...
