rocksdb/db/merge_helper_test.cc
Levi Tamasi dc5de45af8 Support readahead during compaction for blob files (#9187)
Summary:
The patch adds a new BlobDB configuration option `blob_compaction_readahead_size`
that can be used to enable prefetching data from blob files during compaction.
This is important when using storage with higher latencies like HDDs or remote filesystems.
If enabled, prefetching is used for all cases when blobs are read during compaction,
namely garbage collection, compaction filters (when the existing value has to be read from
a blob file), and `Merge` (when the value of the base `Put` is stored in a blob file).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/9187

Test Plan: Ran `make check` and the stress/crash test.

Reviewed By: riversand963

Differential Revision: D32565512

Pulled By: ltamasi

fbshipit-source-id: 87be9cebc3aa01cc227bec6b5f64d827b8164f5d
2021-11-19 17:53:47 -08:00

297 lines
11 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 "db/merge_helper.h"
#include <algorithm>
#include <string>
#include <vector>
#include "db/dbformat.h"
#include "rocksdb/comparator.h"
#include "test_util/testharness.h"
#include "test_util/testutil.h"
#include "util/coding.h"
#include "util/vector_iterator.h"
#include "utilities/merge_operators.h"
namespace ROCKSDB_NAMESPACE {
class MergeHelperTest : public testing::Test {
public:
MergeHelperTest() : icmp_(BytewiseComparator()) { env_ = Env::Default(); }
~MergeHelperTest() override = default;
Status Run(SequenceNumber stop_before, bool at_bottom,
SequenceNumber latest_snapshot = 0) {
iter_.reset(new VectorIterator(ks_, vs_, &icmp_));
iter_->SeekToFirst();
merge_helper_.reset(new MergeHelper(env_, icmp_.user_comparator(),
merge_op_.get(), filter_.get(), nullptr,
false, latest_snapshot));
return merge_helper_->MergeUntil(
iter_.get(), nullptr /* range_del_agg */, stop_before, at_bottom,
false /* allow_data_in_errors */, nullptr /* blob_fetcher */,
nullptr /* prefetch_buffers */, nullptr /* c_iter_stats */);
}
void AddKeyVal(const std::string& user_key, const SequenceNumber& seq,
const ValueType& t, const std::string& val,
bool corrupt = false) {
InternalKey ikey(user_key, seq, t);
if (corrupt) {
test::CorruptKeyType(&ikey);
}
ks_.push_back(ikey.Encode().ToString());
vs_.push_back(val);
}
Env* env_;
InternalKeyComparator icmp_;
std::unique_ptr<VectorIterator> iter_;
std::shared_ptr<MergeOperator> merge_op_;
std::unique_ptr<MergeHelper> merge_helper_;
std::vector<std::string> ks_;
std::vector<std::string> vs_;
std::unique_ptr<test::FilterNumber> filter_;
};
// If MergeHelper encounters a new key on the last level, we know that
// the key has no more history and it can merge keys.
TEST_F(MergeHelperTest, MergeAtBottomSuccess) {
merge_op_ = MergeOperators::CreateUInt64AddOperator();
AddKeyVal("a", 20, kTypeMerge, test::EncodeInt(1U));
AddKeyVal("a", 10, kTypeMerge, test::EncodeInt(3U));
AddKeyVal("b", 10, kTypeMerge, test::EncodeInt(4U)); // <- iter_ after merge
ASSERT_TRUE(Run(0, true).ok());
ASSERT_EQ(ks_[2], iter_->key());
ASSERT_EQ(test::KeyStr("a", 20, kTypeValue), merge_helper_->keys()[0]);
ASSERT_EQ(test::EncodeInt(4U), merge_helper_->values()[0]);
ASSERT_EQ(1U, merge_helper_->keys().size());
ASSERT_EQ(1U, merge_helper_->values().size());
}
// Merging with a value results in a successful merge.
TEST_F(MergeHelperTest, MergeValue) {
merge_op_ = MergeOperators::CreateUInt64AddOperator();
AddKeyVal("a", 40, kTypeMerge, test::EncodeInt(1U));
AddKeyVal("a", 30, kTypeMerge, test::EncodeInt(3U));
AddKeyVal("a", 20, kTypeValue, test::EncodeInt(4U)); // <- iter_ after merge
AddKeyVal("a", 10, kTypeMerge, test::EncodeInt(1U));
ASSERT_TRUE(Run(0, false).ok());
ASSERT_EQ(ks_[3], iter_->key());
ASSERT_EQ(test::KeyStr("a", 40, kTypeValue), merge_helper_->keys()[0]);
ASSERT_EQ(test::EncodeInt(8U), merge_helper_->values()[0]);
ASSERT_EQ(1U, merge_helper_->keys().size());
ASSERT_EQ(1U, merge_helper_->values().size());
}
// Merging stops before a snapshot.
TEST_F(MergeHelperTest, SnapshotBeforeValue) {
merge_op_ = MergeOperators::CreateUInt64AddOperator();
AddKeyVal("a", 50, kTypeMerge, test::EncodeInt(1U));
AddKeyVal("a", 40, kTypeMerge, test::EncodeInt(3U)); // <- iter_ after merge
AddKeyVal("a", 30, kTypeMerge, test::EncodeInt(1U));
AddKeyVal("a", 20, kTypeValue, test::EncodeInt(4U));
AddKeyVal("a", 10, kTypeMerge, test::EncodeInt(1U));
ASSERT_TRUE(Run(31, true).IsMergeInProgress());
ASSERT_EQ(ks_[2], iter_->key());
ASSERT_EQ(test::KeyStr("a", 50, kTypeMerge), merge_helper_->keys()[0]);
ASSERT_EQ(test::EncodeInt(4U), merge_helper_->values()[0]);
ASSERT_EQ(1U, merge_helper_->keys().size());
ASSERT_EQ(1U, merge_helper_->values().size());
}
// MergeHelper preserves the operand stack for merge operators that
// cannot do a partial merge.
TEST_F(MergeHelperTest, NoPartialMerge) {
merge_op_ = MergeOperators::CreateStringAppendTESTOperator();
AddKeyVal("a", 50, kTypeMerge, "v2");
AddKeyVal("a", 40, kTypeMerge, "v"); // <- iter_ after merge
AddKeyVal("a", 30, kTypeMerge, "v");
ASSERT_TRUE(Run(31, true).IsMergeInProgress());
ASSERT_EQ(ks_[2], iter_->key());
ASSERT_EQ(test::KeyStr("a", 40, kTypeMerge), merge_helper_->keys()[0]);
ASSERT_EQ("v", merge_helper_->values()[0]);
ASSERT_EQ(test::KeyStr("a", 50, kTypeMerge), merge_helper_->keys()[1]);
ASSERT_EQ("v2", merge_helper_->values()[1]);
ASSERT_EQ(2U, merge_helper_->keys().size());
ASSERT_EQ(2U, merge_helper_->values().size());
}
// A single operand can not be merged.
TEST_F(MergeHelperTest, SingleOperand) {
merge_op_ = MergeOperators::CreateUInt64AddOperator();
AddKeyVal("a", 50, kTypeMerge, test::EncodeInt(1U));
ASSERT_TRUE(Run(31, false).IsMergeInProgress());
ASSERT_FALSE(iter_->Valid());
ASSERT_EQ(test::KeyStr("a", 50, kTypeMerge), merge_helper_->keys()[0]);
ASSERT_EQ(test::EncodeInt(1U), merge_helper_->values()[0]);
ASSERT_EQ(1U, merge_helper_->keys().size());
ASSERT_EQ(1U, merge_helper_->values().size());
}
// Merging with a deletion turns the deletion into a value
TEST_F(MergeHelperTest, MergeDeletion) {
merge_op_ = MergeOperators::CreateUInt64AddOperator();
AddKeyVal("a", 30, kTypeMerge, test::EncodeInt(3U));
AddKeyVal("a", 20, kTypeDeletion, "");
ASSERT_TRUE(Run(15, false).ok());
ASSERT_FALSE(iter_->Valid());
ASSERT_EQ(test::KeyStr("a", 30, kTypeValue), merge_helper_->keys()[0]);
ASSERT_EQ(test::EncodeInt(3U), merge_helper_->values()[0]);
ASSERT_EQ(1U, merge_helper_->keys().size());
ASSERT_EQ(1U, merge_helper_->values().size());
}
// The merge helper stops upon encountering a corrupt key
TEST_F(MergeHelperTest, CorruptKey) {
merge_op_ = MergeOperators::CreateUInt64AddOperator();
AddKeyVal("a", 30, kTypeMerge, test::EncodeInt(3U));
AddKeyVal("a", 25, kTypeMerge, test::EncodeInt(1U));
// Corrupt key
AddKeyVal("a", 20, kTypeDeletion, "", true); // <- iter_ after merge
ASSERT_TRUE(Run(15, false).IsMergeInProgress());
ASSERT_EQ(ks_[2], iter_->key());
ASSERT_EQ(test::KeyStr("a", 30, kTypeMerge), merge_helper_->keys()[0]);
ASSERT_EQ(test::EncodeInt(4U), merge_helper_->values()[0]);
ASSERT_EQ(1U, merge_helper_->keys().size());
ASSERT_EQ(1U, merge_helper_->values().size());
}
// The compaction filter is called on every merge operand
TEST_F(MergeHelperTest, FilterMergeOperands) {
merge_op_ = MergeOperators::CreateUInt64AddOperator();
filter_.reset(new test::FilterNumber(5U));
AddKeyVal("a", 30, kTypeMerge, test::EncodeInt(3U));
AddKeyVal("a", 29, kTypeMerge, test::EncodeInt(5U)); // Filtered
AddKeyVal("a", 28, kTypeMerge, test::EncodeInt(3U));
AddKeyVal("a", 27, kTypeMerge, test::EncodeInt(1U));
AddKeyVal("a", 26, kTypeMerge, test::EncodeInt(5U)); // Filtered
AddKeyVal("a", 25, kTypeValue, test::EncodeInt(1U));
ASSERT_TRUE(Run(15, false).ok());
ASSERT_FALSE(iter_->Valid());
MergeOutputIterator merge_output_iter(merge_helper_.get());
merge_output_iter.SeekToFirst();
ASSERT_EQ(test::KeyStr("a", 30, kTypeValue),
merge_output_iter.key().ToString());
ASSERT_EQ(test::EncodeInt(8U), merge_output_iter.value().ToString());
merge_output_iter.Next();
ASSERT_FALSE(merge_output_iter.Valid());
}
TEST_F(MergeHelperTest, FilterAllMergeOperands) {
merge_op_ = MergeOperators::CreateUInt64AddOperator();
filter_.reset(new test::FilterNumber(5U));
AddKeyVal("a", 30, kTypeMerge, test::EncodeInt(5U));
AddKeyVal("a", 29, kTypeMerge, test::EncodeInt(5U));
AddKeyVal("a", 28, kTypeMerge, test::EncodeInt(5U));
AddKeyVal("a", 27, kTypeMerge, test::EncodeInt(5U));
AddKeyVal("a", 26, kTypeMerge, test::EncodeInt(5U));
AddKeyVal("a", 25, kTypeMerge, test::EncodeInt(5U));
// filtered out all
ASSERT_TRUE(Run(15, false).ok());
ASSERT_FALSE(iter_->Valid());
MergeOutputIterator merge_output_iter(merge_helper_.get());
merge_output_iter.SeekToFirst();
ASSERT_FALSE(merge_output_iter.Valid());
// we have one operand that will survive because it's a delete
AddKeyVal("a", 24, kTypeDeletion, test::EncodeInt(5U));
AddKeyVal("b", 23, kTypeValue, test::EncodeInt(5U));
ASSERT_TRUE(Run(15, true).ok());
merge_output_iter = MergeOutputIterator(merge_helper_.get());
ASSERT_TRUE(iter_->Valid());
merge_output_iter.SeekToFirst();
ASSERT_FALSE(merge_output_iter.Valid());
// when all merge operands are filtered out, we leave the iterator pointing to
// the Put/Delete that survived
ASSERT_EQ(test::KeyStr("a", 24, kTypeDeletion), iter_->key().ToString());
ASSERT_EQ(test::EncodeInt(5U), iter_->value().ToString());
}
// Make sure that merge operands are filtered at the beginning
TEST_F(MergeHelperTest, FilterFirstMergeOperand) {
merge_op_ = MergeOperators::CreateUInt64AddOperator();
filter_.reset(new test::FilterNumber(5U));
AddKeyVal("a", 31, kTypeMerge, test::EncodeInt(5U)); // Filtered
AddKeyVal("a", 30, kTypeMerge, test::EncodeInt(5U)); // Filtered
AddKeyVal("a", 29, kTypeMerge, test::EncodeInt(2U));
AddKeyVal("a", 28, kTypeMerge, test::EncodeInt(1U));
AddKeyVal("a", 27, kTypeMerge, test::EncodeInt(3U));
AddKeyVal("a", 26, kTypeMerge, test::EncodeInt(5U)); // Filtered
AddKeyVal("a", 25, kTypeMerge, test::EncodeInt(5U)); // Filtered
AddKeyVal("b", 24, kTypeValue, test::EncodeInt(5U)); // next user key
ASSERT_OK(Run(15, true));
ASSERT_TRUE(iter_->Valid());
MergeOutputIterator merge_output_iter(merge_helper_.get());
merge_output_iter.SeekToFirst();
// sequence number is 29 here, because the first merge operand got filtered
// out
ASSERT_EQ(test::KeyStr("a", 29, kTypeValue),
merge_output_iter.key().ToString());
ASSERT_EQ(test::EncodeInt(6U), merge_output_iter.value().ToString());
merge_output_iter.Next();
ASSERT_FALSE(merge_output_iter.Valid());
// make sure that we're passing user keys into the filter
ASSERT_EQ("a", filter_->last_merge_operand_key());
}
// Make sure that merge operands are not filtered out if there's a snapshot
// pointing at them
TEST_F(MergeHelperTest, DontFilterMergeOperandsBeforeSnapshotTest) {
merge_op_ = MergeOperators::CreateUInt64AddOperator();
filter_.reset(new test::FilterNumber(5U));
AddKeyVal("a", 31, kTypeMerge, test::EncodeInt(5U));
AddKeyVal("a", 30, kTypeMerge, test::EncodeInt(5U));
AddKeyVal("a", 29, kTypeMerge, test::EncodeInt(2U));
AddKeyVal("a", 28, kTypeMerge, test::EncodeInt(1U));
AddKeyVal("a", 27, kTypeMerge, test::EncodeInt(3U));
AddKeyVal("a", 26, kTypeMerge, test::EncodeInt(5U));
AddKeyVal("a", 25, kTypeMerge, test::EncodeInt(5U));
AddKeyVal("b", 24, kTypeValue, test::EncodeInt(5U));
ASSERT_OK(Run(15, true, 32));
ASSERT_TRUE(iter_->Valid());
MergeOutputIterator merge_output_iter(merge_helper_.get());
merge_output_iter.SeekToFirst();
ASSERT_EQ(test::KeyStr("a", 31, kTypeValue),
merge_output_iter.key().ToString());
ASSERT_EQ(test::EncodeInt(26U), merge_output_iter.value().ToString());
merge_output_iter.Next();
ASSERT_FALSE(merge_output_iter.Valid());
}
} // namespace ROCKSDB_NAMESPACE
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}