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rocksdb/db/db_iter_stress_test.cc
mrambacher 8948dc8524 Make ImmutableOptions struct that inherits from ImmutableCFOptions and ImmutableDBOptions (#8262) 
Summary:
The ImmutableCFOptions contained a bunch of fields that belonged to the ImmutableDBOptions.  This change cleans that up by introducing an ImmutableOptions struct.  Following the pattern of Options struct, this class inherits from the DB and CFOption structs (of the Immutable form).

Only one structural change (the ImmutableCFOptions::fs was changed to a shared_ptr from a raw one) is in this PR.  All of the other changes involve moving the member variables from the ImmutableCFOptions into the ImmutableOptions and changing member variables or function parameters as required for compilation purposes.

Follow-on PRs may do a further clean-up of the code, such as renaming variables (such as "ImmutableOptions cf_options") and potentially eliminating un-needed function parameters (there is no longer a need to pass both an ImmutableDBOptions and an ImmutableOptions to a function).

Pull Request resolved: https://github.com/facebook/rocksdb/pull/8262

Reviewed By: pdillinger

Differential Revision: D28226540

Pulled By: mrambacher

fbshipit-source-id: 18ae71eadc879dedbe38b1eb8e6f9ff5c7147dbf
2021-05-05 14:00:17 -07:00

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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).
#include "db/db_iter.h"
#include "db/dbformat.h"
#include "rocksdb/comparator.h"
#include "rocksdb/options.h"
#include "rocksdb/slice.h"
#include "test_util/testharness.h"
#include "util/random.h"
#include "util/string_util.h"
#include "utilities/merge_operators.h"
#ifdef GFLAGS
#include "util/gflags_compat.h"
using GFLAGS_NAMESPACE::ParseCommandLineFlags;
DEFINE_bool(verbose, false,
"Print huge, detailed trace. Intended for debugging failures.");
#else
void ParseCommandLineFlags(int*, char***, bool) {}
bool FLAGS_verbose = false;
#endif
namespace ROCKSDB_NAMESPACE {
class DBIteratorStressTest : public testing::Test {
public:
Env* env_;
DBIteratorStressTest() : env_(Env::Default()) {}
};
namespace {
struct Entry {
std::string key;
ValueType type; // kTypeValue, kTypeDeletion, kTypeMerge
uint64_t sequence;
std::string ikey; // internal key, made from `key`, `sequence` and `type`
std::string value;
// If false, we'll pretend that this entry doesn't exist.
bool visible = true;
bool operator<(const Entry& e) const {
if (key != e.key) return key < e.key;
return std::tie(sequence, type) > std::tie(e.sequence, e.type);
}
};
struct Data {
std::vector<Entry> entries;
// Indices in `entries` with `visible` = false.
std::vector<size_t> hidden;
// Keys of entries whose `visible` changed since the last seek of iterators.
std::set<std::string> recently_touched_keys;
};
struct StressTestIterator : public InternalIterator {
Data* data;
Random64* rnd;
InternalKeyComparator cmp;
// Each operation will return error with this probability...
double error_probability = 0;
// ... and add/remove entries with this probability.
double mutation_probability = 0;
// The probability of adding vs removing entries will be chosen so that the
// amount of removed entries stays somewhat close to this number.
double target_hidden_fraction = 0;
// If true, print all mutations to stdout for debugging.
bool trace = false;
int iter = -1;
Status status_;
StressTestIterator(Data* _data, Random64* _rnd, const Comparator* _cmp)
: data(_data), rnd(_rnd), cmp(_cmp) {}
bool Valid() const override {
if (iter >= 0 && iter < (int)data->entries.size()) {
assert(status_.ok());
return true;
}
return false;
}
Status status() const override { return status_; }
bool MaybeFail() {
if (rnd->Next() >=
static_cast<double>(std::numeric_limits<uint64_t>::max()) *
error_probability) {
return false;
}
if (rnd->Next() % 2) {
status_ = Status::Incomplete("test");
} else {
status_ = Status::IOError("test");
}
if (trace) {
std::cout << "injecting " << status_.ToString() << std::endl;
}
iter = -1;
return true;
}
void MaybeMutate() {
if (rnd->Next() >=
static_cast<double>(std::numeric_limits<uint64_t>::max()) *
mutation_probability) {
return;
}
do {
// If too many entries are hidden, hide less, otherwise hide more.
double hide_probability =
data->hidden.size() > data->entries.size() * target_hidden_fraction
? 1. / 3
: 2. / 3;
if (data->hidden.empty()) {
hide_probability = 1;
}
bool do_hide = rnd->Next() <
static_cast<double>(std::numeric_limits<uint64_t>::max()) *
hide_probability;
if (do_hide) {
// Hide a random entry.
size_t idx = rnd->Next() % data->entries.size();
Entry& e = data->entries[idx];
if (e.visible) {
if (trace) {
std::cout << "hiding idx " << idx << std::endl;
}
e.visible = false;
data->hidden.push_back(idx);
data->recently_touched_keys.insert(e.key);
} else {
// Already hidden. Let's go unhide something instead, just because
// it's easy and it doesn't really matter what we do.
do_hide = false;
}
}
if (!do_hide) {
// Unhide a random entry.
size_t hi = rnd->Next() % data->hidden.size();
size_t idx = data->hidden[hi];
if (trace) {
std::cout << "unhiding idx " << idx << std::endl;
}
Entry& e = data->entries[idx];
assert(!e.visible);
e.visible = true;
data->hidden[hi] = data->hidden.back();
data->hidden.pop_back();
data->recently_touched_keys.insert(e.key);
}
} while (rnd->Next() % 3 != 0); // do 3 mutations on average
}
void SkipForward() {
while (iter < (int)data->entries.size() && !data->entries[iter].visible) {
++iter;
}
}
void SkipBackward() {
while (iter >= 0 && !data->entries[iter].visible) {
--iter;
}
}
void SeekToFirst() override {
if (MaybeFail()) return;
MaybeMutate();
status_ = Status::OK();
iter = 0;
SkipForward();
}
void SeekToLast() override {
if (MaybeFail()) return;
MaybeMutate();
status_ = Status::OK();
iter = (int)data->entries.size() - 1;
SkipBackward();
}
void Seek(const Slice& target) override {
if (MaybeFail()) return;
MaybeMutate();
status_ = Status::OK();
// Binary search.
auto it = std::partition_point(
data->entries.begin(), data->entries.end(),
[&](const Entry& e) { return cmp.Compare(e.ikey, target) < 0; });
iter = (int)(it - data->entries.begin());
SkipForward();
}
void SeekForPrev(const Slice& target) override {
if (MaybeFail()) return;
MaybeMutate();
status_ = Status::OK();
// Binary search.
auto it = std::partition_point(
data->entries.begin(), data->entries.end(),
[&](const Entry& e) { return cmp.Compare(e.ikey, target) <= 0; });
iter = (int)(it - data->entries.begin());
--iter;
SkipBackward();
}
void Next() override {
assert(Valid());
if (MaybeFail()) return;
MaybeMutate();
++iter;
SkipForward();
}
void Prev() override {
assert(Valid());
if (MaybeFail()) return;
MaybeMutate();
--iter;
SkipBackward();
}
Slice key() const override {
assert(Valid());
return data->entries[iter].ikey;
}
Slice value() const override {
assert(Valid());
return data->entries[iter].value;
}
bool IsKeyPinned() const override { return true; }
bool IsValuePinned() const override { return true; }
};
// A small reimplementation of DBIter, supporting only some of the features,
// and doing everything in O(log n).
// Skips all keys that are in recently_touched_keys.
struct ReferenceIterator {
Data* data;
uint64_t sequence; // ignore entries with sequence number below this
bool valid = false;
std::string key;
std::string value;
ReferenceIterator(Data* _data, uint64_t _sequence)
: data(_data), sequence(_sequence) {}
bool Valid() const { return valid; }
// Finds the first entry with key
// greater/less/greater-or-equal/less-or-equal than `key`, depending on
// arguments: if `skip`, inequality is strict; if `forward`, it's
// greater/greater-or-equal, otherwise less/less-or-equal.
// Sets `key` to the result.
// If no such key exists, returns false. Doesn't check `visible`.
bool FindNextKey(bool skip, bool forward) {
valid = false;
auto it = std::partition_point(data->entries.begin(), data->entries.end(),
[&](const Entry& e) {
if (forward != skip) {
return e.key < key;
} else {
return e.key <= key;
}
});
if (forward) {
if (it != data->entries.end()) {
key = it->key;
return true;
}
} else {
if (it != data->entries.begin()) {
--it;
key = it->key;
return true;
}
}
return false;
}
bool FindValueForCurrentKey() {
if (data->recently_touched_keys.count(key)) {
return false;
}
// Find the first entry for the key. The caller promises that it exists.
auto it = std::partition_point(data->entries.begin(), data->entries.end(),
[&](const Entry& e) {
if (e.key != key) {
return e.key < key;
}
return e.sequence > sequence;
});
// Find the first visible entry.
for (;; ++it) {
if (it == data->entries.end()) {
return false;
}
Entry& e = *it;
if (e.key != key) {
return false;
}
assert(e.sequence <= sequence);
if (!e.visible) continue;
if (e.type == kTypeDeletion) {
return false;
}
if (e.type == kTypeValue) {
value = e.value;
valid = true;
return true;
}
assert(e.type == kTypeMerge);
break;
}
// Collect merge operands.
std::vector<Slice> operands;
for (; it != data->entries.end(); ++it) {
Entry& e = *it;
if (e.key != key) {
break;
}
assert(e.sequence <= sequence);
if (!e.visible) continue;
if (e.type == kTypeDeletion) {
break;
}
operands.push_back(e.value);
if (e.type == kTypeValue) {
break;
}
}
// Do a merge.
value = operands.back().ToString();
for (int i = (int)operands.size() - 2; i >= 0; --i) {
value.append(",");
value.append(operands[i].data(), operands[i].size());
}
valid = true;
return true;
}
// Start at `key` and move until we encounter a valid value.
// `forward` defines the direction of movement.
// If `skip` is true, we're looking for key not equal to `key`.
void DoTheThing(bool skip, bool forward) {
while (FindNextKey(skip, forward) && !FindValueForCurrentKey()) {
skip = true;
}
}
void Seek(const Slice& target) {
key = target.ToString();
DoTheThing(false, true);
}
void SeekForPrev(const Slice& target) {
key = target.ToString();
DoTheThing(false, false);
}
void SeekToFirst() { Seek(""); }
void SeekToLast() {
key = data->entries.back().key;
DoTheThing(false, false);
}
void Next() {
assert(Valid());
DoTheThing(true, true);
}
void Prev() {
assert(Valid());
DoTheThing(true, false);
}
};
} // namespace
// Use an internal iterator that sometimes returns errors and sometimes
// adds/removes entries on the fly. Do random operations on a DBIter and
// check results.
// TODO: can be improved for more coverage:
// * Override IsKeyPinned() and IsValuePinned() to actually use
// PinnedIteratorManager and check that there's no use-after free.
// * Try different combinations of prefix_extractor, total_order_seek,
// prefix_same_as_start, iterate_lower_bound, iterate_upper_bound.
TEST_F(DBIteratorStressTest, StressTest) {
// We use a deterministic RNG, and everything happens in a single thread.
Random64 rnd(826909345792864532ll);
auto gen_key = [&](int max_key) {
assert(max_key > 0);
int len = 0;
int a = max_key;
while (a) {
a /= 10;
++len;
}
std::string s = ToString(rnd.Next() % static_cast<uint64_t>(max_key));
s.insert(0, len - (int)s.size(), '0');
return s;
};
Options options;
options.merge_operator = MergeOperators::CreateFromStringId("stringappend");
ReadOptions ropt;
size_t num_matching = 0;
size_t num_at_end = 0;
size_t num_not_ok = 0;
size_t num_recently_removed = 0;
// Number of iterations for each combination of parameters
// (there are ~250 of those).
// Tweak this to change the test run time.
// As of the time of writing, the test takes ~4 seconds for value of 5000.
const int num_iterations = 5000;
// Enable this to print all the operations for debugging.
bool trace = FLAGS_verbose;
for (int num_entries : {5, 10, 100}) {
for (double key_space : {0.1, 1.0, 3.0}) {
for (ValueType prevalent_entry_type :
{kTypeValue, kTypeDeletion, kTypeMerge}) {
for (double error_probability : {0.01, 0.1}) {
for (double mutation_probability : {0.01, 0.5}) {
for (double target_hidden_fraction : {0.1, 0.5}) {
std::string trace_str =
"entries: " + ToString(num_entries) +
", key_space: " + ToString(key_space) +
", error_probability: " + ToString(error_probability) +
", mutation_probability: " + ToString(mutation_probability) +
", target_hidden_fraction: " +
ToString(target_hidden_fraction);
SCOPED_TRACE(trace_str);
if (trace) {
std::cout << trace_str << std::endl;
}
// Generate data.
Data data;
int max_key = (int)(num_entries * key_space) + 1;
for (int i = 0; i < num_entries; ++i) {
Entry e;
e.key = gen_key(max_key);
if (rnd.Next() % 10 != 0) {
e.type = prevalent_entry_type;
} else {
const ValueType types[] = {kTypeValue, kTypeDeletion,
kTypeMerge};
e.type =
types[rnd.Next() % (sizeof(types) / sizeof(types[0]))];
}
e.sequence = i;
e.value = "v" + ToString(i);
ParsedInternalKey internal_key(e.key, e.sequence, e.type);
AppendInternalKey(&e.ikey, internal_key);
data.entries.push_back(e);
}
std::sort(data.entries.begin(), data.entries.end());
if (trace) {
std::cout << "entries:";
for (size_t i = 0; i < data.entries.size(); ++i) {
Entry& e = data.entries[i];
std::cout
<< "\n idx " << i << ": \"" << e.key << "\": \""
<< e.value << "\" seq: " << e.sequence << " type: "
<< (e.type == kTypeValue
? "val"
: e.type == kTypeDeletion ? "del" : "merge");
}
std::cout << std::endl;
}
std::unique_ptr<Iterator> db_iter;
std::unique_ptr<ReferenceIterator> ref_iter;
for (int iteration = 0; iteration < num_iterations; ++iteration) {
SCOPED_TRACE(iteration);
// Create a new iterator every ~30 operations.
if (db_iter == nullptr || rnd.Next() % 30 == 0) {
uint64_t sequence = rnd.Next() % (data.entries.size() + 2);
ref_iter.reset(new ReferenceIterator(&data, sequence));
if (trace) {
std::cout << "new iterator, seq: " << sequence << std::endl;
}
auto internal_iter =
new StressTestIterator(&data, &rnd, BytewiseComparator());
internal_iter->error_probability = error_probability;
internal_iter->mutation_probability = mutation_probability;
internal_iter->target_hidden_fraction =
target_hidden_fraction;
internal_iter->trace = trace;
db_iter.reset(NewDBIterator(
env_, ropt, ImmutableOptions(options),
MutableCFOptions(options), BytewiseComparator(),
internal_iter, nullptr /* version */, sequence,
options.max_sequential_skip_in_iterations,
nullptr /*read_callback*/));
}
// Do a random operation. It's important to do it on ref_it
// later than on db_iter to make sure ref_it sees the correct
// recently_touched_keys.
std::string old_key;
bool forward = rnd.Next() % 2 > 0;
// Do Next()/Prev() ~90% of the time.
bool seek = !ref_iter->Valid() || rnd.Next() % 10 == 0;
if (trace) {
std::cout << iteration << ": ";
}
if (!seek) {
assert(db_iter->Valid());
old_key = ref_iter->key;
if (trace) {
std::cout << (forward ? "Next" : "Prev") << std::endl;
}
if (forward) {
db_iter->Next();
ref_iter->Next();
} else {
db_iter->Prev();
ref_iter->Prev();
}
} else {
data.recently_touched_keys.clear();
// Do SeekToFirst less often than Seek.
if (rnd.Next() % 4 == 0) {
if (trace) {
std::cout << (forward ? "SeekToFirst" : "SeekToLast")
<< std::endl;
}
if (forward) {
old_key = "";
db_iter->SeekToFirst();
ref_iter->SeekToFirst();
} else {
old_key = data.entries.back().key;
db_iter->SeekToLast();
ref_iter->SeekToLast();
}
} else {
old_key = gen_key(max_key);
if (trace) {
std::cout << (forward ? "Seek" : "SeekForPrev") << " \""
<< old_key << '"' << std::endl;
}
if (forward) {
db_iter->Seek(old_key);
ref_iter->Seek(old_key);
} else {
db_iter->SeekForPrev(old_key);
ref_iter->SeekForPrev(old_key);
}
}
}
// Check the result.
if (db_iter->Valid()) {
ASSERT_TRUE(db_iter->status().ok());
if (data.recently_touched_keys.count(
db_iter->key().ToString())) {
// Ended on a key that may have been mutated during the
// operation. Reference iterator skips such keys, so we
// can't check the exact result.
// Check that the key moved in the right direction.
if (forward) {
if (seek)
ASSERT_GE(db_iter->key().ToString(), old_key);
else
ASSERT_GT(db_iter->key().ToString(), old_key);
} else {
if (seek)
ASSERT_LE(db_iter->key().ToString(), old_key);
else
ASSERT_LT(db_iter->key().ToString(), old_key);
}
if (ref_iter->Valid()) {
// Check that DBIter didn't miss any non-mutated key.
if (forward) {
ASSERT_LT(db_iter->key().ToString(), ref_iter->key);
} else {
ASSERT_GT(db_iter->key().ToString(), ref_iter->key);
}
}
// Tell the next iteration of the loop to reseek the
// iterators.
ref_iter->valid = false;
++num_recently_removed;
} else {
ASSERT_TRUE(ref_iter->Valid());
ASSERT_EQ(ref_iter->key, db_iter->key().ToString());
ASSERT_EQ(ref_iter->value, db_iter->value());
++num_matching;
}
} else if (db_iter->status().ok()) {
ASSERT_FALSE(ref_iter->Valid());
++num_at_end;
} else {
// Non-ok status. Nothing to check here.
// Tell the next iteration of the loop to reseek the
// iterators.
ref_iter->valid = false;
++num_not_ok;
}
}
}
}
}
}
}
}
// Check that all cases were hit many times.
EXPECT_GT(num_matching, 10000);
EXPECT_GT(num_at_end, 10000);
EXPECT_GT(num_not_ok, 10000);
EXPECT_GT(num_recently_removed, 10000);
std::cout << "stats:\n exact matches: " << num_matching
<< "\n end reached: " << num_at_end
<< "\n non-ok status: " << num_not_ok
<< "\n mutated on the fly: " << num_recently_removed << std::endl;
}
} // namespace ROCKSDB_NAMESPACE
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
ParseCommandLineFlags(&argc, &argv, true);
return RUN_ALL_TESTS();
}
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