c3ebc75843
Summary: Currently it is not possible to change bloom filter config without restart the db, which is causing a lot of operational complexity for users. This PR aims to make it possible to dynamically change bloom filter config. Closes https://github.com/facebook/rocksdb/pull/3601 Differential Revision: D7253114 Pulled By: miasantreble fbshipit-source-id: f22595437d3e0b86c95918c484502de2ceca120c
655 lines
21 KiB
C++
655 lines
21 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#include "db/db_iter.h"
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#include "db/dbformat.h"
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#include "rocksdb/comparator.h"
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#include "rocksdb/options.h"
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#include "rocksdb/slice.h"
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#include "util/random.h"
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#include "util/string_util.h"
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#include "util/testharness.h"
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#include "utilities/merge_operators.h"
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#ifdef GFLAGS
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#include "util/gflags_compat.h"
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using GFLAGS_NAMESPACE::ParseCommandLineFlags;
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DEFINE_bool(verbose, false,
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"Print huge, detailed trace. Intended for debugging failures.");
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#else
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void ParseCommandLineFlags(int*, char***, bool) {}
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bool FLAGS_verbose = false;
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#endif
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namespace rocksdb {
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class DBIteratorStressTest : public testing::Test {
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public:
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Env* env_;
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DBIteratorStressTest() : env_(Env::Default()) {}
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};
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namespace {
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struct Entry {
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std::string key;
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ValueType type; // kTypeValue, kTypeDeletion, kTypeMerge
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uint64_t sequence;
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std::string ikey; // internal key, made from `key`, `sequence` and `type`
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std::string value;
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// If false, we'll pretend that this entry doesn't exist.
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bool visible = true;
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bool operator<(const Entry& e) const {
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if (key != e.key) return key < e.key;
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return std::tie(sequence, type) > std::tie(e.sequence, e.type);
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}
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};
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struct Data {
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std::vector<Entry> entries;
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// Indices in `entries` with `visible` = false.
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std::vector<size_t> hidden;
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// Keys of entries whose `visible` changed since the last seek of iterators.
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std::set<std::string> recently_touched_keys;
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};
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struct StressTestIterator : public InternalIterator {
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Data* data;
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Random64* rnd;
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InternalKeyComparator cmp;
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// Each operation will return error with this probability...
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double error_probability = 0;
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// ... and add/remove entries with this probability.
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double mutation_probability = 0;
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// The probability of adding vs removing entries will be chosen so that the
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// amount of removed entries stays somewhat close to this number.
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double target_hidden_fraction = 0;
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// If true, print all mutations to stdout for debugging.
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bool trace = false;
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int iter = -1;
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Status status_;
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StressTestIterator(Data* _data, Random64* _rnd, const Comparator* _cmp)
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: data(_data), rnd(_rnd), cmp(_cmp) {}
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bool Valid() const override {
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if (iter >= 0 && iter < (int)data->entries.size()) {
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assert(status_.ok());
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return true;
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}
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return false;
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}
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Status status() const override { return status_; }
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bool MaybeFail() {
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if (rnd->Next() >=
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std::numeric_limits<uint64_t>::max() * error_probability) {
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return false;
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}
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if (rnd->Next() % 2) {
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status_ = Status::Incomplete("test");
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} else {
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status_ = Status::IOError("test");
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}
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if (trace) {
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std::cout << "injecting " << status_.ToString() << std::endl;
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}
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iter = -1;
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return true;
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}
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void MaybeMutate() {
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if (rnd->Next() >=
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std::numeric_limits<uint64_t>::max() * mutation_probability) {
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return;
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}
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do {
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// If too many entries are hidden, hide less, otherwise hide more.
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double hide_probability =
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data->hidden.size() > data->entries.size() * target_hidden_fraction
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? 1. / 3
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: 2. / 3;
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if (data->hidden.empty()) {
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hide_probability = 1;
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}
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bool do_hide =
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rnd->Next() < std::numeric_limits<uint64_t>::max() * hide_probability;
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if (do_hide) {
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// Hide a random entry.
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size_t idx = rnd->Next() % data->entries.size();
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Entry& e = data->entries[idx];
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if (e.visible) {
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if (trace) {
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std::cout << "hiding idx " << idx << std::endl;
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}
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e.visible = false;
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data->hidden.push_back(idx);
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data->recently_touched_keys.insert(e.key);
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} else {
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// Already hidden. Let's go unhide something instead, just because
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// it's easy and it doesn't really matter what we do.
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do_hide = false;
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}
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}
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if (!do_hide) {
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// Unhide a random entry.
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size_t hi = rnd->Next() % data->hidden.size();
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size_t idx = data->hidden[hi];
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if (trace) {
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std::cout << "unhiding idx " << idx << std::endl;
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}
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Entry& e = data->entries[idx];
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assert(!e.visible);
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e.visible = true;
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data->hidden[hi] = data->hidden.back();
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data->hidden.pop_back();
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data->recently_touched_keys.insert(e.key);
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}
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} while (rnd->Next() % 3 != 0); // do 3 mutations on average
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}
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void SkipForward() {
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while (iter < (int)data->entries.size() && !data->entries[iter].visible) {
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++iter;
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}
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}
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void SkipBackward() {
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while (iter >= 0 && !data->entries[iter].visible) {
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--iter;
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}
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}
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void SeekToFirst() override {
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if (MaybeFail()) return;
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MaybeMutate();
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status_ = Status::OK();
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iter = 0;
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SkipForward();
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}
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void SeekToLast() override {
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if (MaybeFail()) return;
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MaybeMutate();
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status_ = Status::OK();
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iter = (int)data->entries.size() - 1;
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SkipBackward();
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}
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void Seek(const Slice& target) override {
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if (MaybeFail()) return;
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MaybeMutate();
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status_ = Status::OK();
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// Binary search.
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auto it = std::partition_point(
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data->entries.begin(), data->entries.end(),
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[&](const Entry& e) { return cmp.Compare(e.ikey, target) < 0; });
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iter = (int)(it - data->entries.begin());
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SkipForward();
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}
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void SeekForPrev(const Slice& target) override {
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if (MaybeFail()) return;
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MaybeMutate();
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status_ = Status::OK();
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// Binary search.
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auto it = std::partition_point(
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data->entries.begin(), data->entries.end(),
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[&](const Entry& e) { return cmp.Compare(e.ikey, target) <= 0; });
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iter = (int)(it - data->entries.begin());
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--iter;
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SkipBackward();
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}
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void Next() override {
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assert(Valid());
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if (MaybeFail()) return;
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MaybeMutate();
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++iter;
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SkipForward();
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}
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void Prev() override {
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assert(Valid());
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if (MaybeFail()) return;
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MaybeMutate();
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--iter;
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SkipBackward();
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}
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Slice key() const override {
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assert(Valid());
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return data->entries[iter].ikey;
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}
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Slice value() const override {
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assert(Valid());
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return data->entries[iter].value;
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}
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bool IsKeyPinned() const override { return true; }
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bool IsValuePinned() const override { return true; }
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};
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// A small reimplementation of DBIter, supporting only some of the features,
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// and doing everything in O(log n).
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// Skips all keys that are in recently_touched_keys.
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struct ReferenceIterator {
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Data* data;
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uint64_t sequence; // ignore entries with sequence number below this
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bool valid = false;
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std::string key;
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std::string value;
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ReferenceIterator(Data* _data, uint64_t _sequence)
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: data(_data), sequence(_sequence) {}
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bool Valid() const { return valid; }
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// Finds the first entry with key
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// greater/less/greater-or-equal/less-or-equal than `key`, depending on
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// arguments: if `skip`, inequality is strict; if `forward`, it's
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// greater/greater-or-equal, otherwise less/less-or-equal.
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// Sets `key` to the result.
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// If no such key exists, returns false. Doesn't check `visible`.
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bool FindNextKey(bool skip, bool forward) {
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valid = false;
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auto it = std::partition_point(data->entries.begin(), data->entries.end(),
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[&](const Entry& e) {
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if (forward != skip) {
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return e.key < key;
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} else {
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return e.key <= key;
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}
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});
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if (forward) {
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if (it != data->entries.end()) {
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key = it->key;
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return true;
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}
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} else {
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if (it != data->entries.begin()) {
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--it;
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key = it->key;
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return true;
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}
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}
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return false;
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}
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bool FindValueForCurrentKey() {
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if (data->recently_touched_keys.count(key)) {
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return false;
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}
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// Find the first entry for the key. The caller promises that it exists.
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auto it = std::partition_point(data->entries.begin(), data->entries.end(),
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[&](const Entry& e) {
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if (e.key != key) {
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return e.key < key;
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}
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return e.sequence > sequence;
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});
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// Find the first visible entry.
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for (;; ++it) {
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if (it == data->entries.end()) {
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return false;
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}
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Entry& e = *it;
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if (e.key != key) {
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return false;
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}
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assert(e.sequence <= sequence);
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if (!e.visible) continue;
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if (e.type == kTypeDeletion) {
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return false;
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}
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if (e.type == kTypeValue) {
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value = e.value;
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valid = true;
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return true;
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}
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assert(e.type == kTypeMerge);
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break;
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}
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// Collect merge operands.
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std::vector<Slice> operands;
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for (; it != data->entries.end(); ++it) {
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Entry& e = *it;
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if (e.key != key) {
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break;
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}
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assert(e.sequence <= sequence);
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if (!e.visible) continue;
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if (e.type == kTypeDeletion) {
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break;
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}
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operands.push_back(e.value);
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if (e.type == kTypeValue) {
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break;
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}
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}
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// Do a merge.
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value = operands.back().ToString();
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for (int i = (int)operands.size() - 2; i >= 0; --i) {
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value.append(",");
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value.append(operands[i].data(), operands[i].size());
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}
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valid = true;
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return true;
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}
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// Start at `key` and move until we encounter a valid value.
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// `forward` defines the direction of movement.
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// If `skip` is true, we're looking for key not equal to `key`.
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void DoTheThing(bool skip, bool forward) {
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while (FindNextKey(skip, forward) && !FindValueForCurrentKey()) {
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skip = true;
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}
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}
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void Seek(const Slice& target) {
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key = target.ToString();
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DoTheThing(false, true);
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}
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void SeekForPrev(const Slice& target) {
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key = target.ToString();
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DoTheThing(false, false);
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}
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void SeekToFirst() { Seek(""); }
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void SeekToLast() {
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key = data->entries.back().key;
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DoTheThing(false, false);
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}
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void Next() {
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assert(Valid());
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DoTheThing(true, true);
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}
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void Prev() {
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assert(Valid());
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DoTheThing(true, false);
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}
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};
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} // namespace
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// Use an internal iterator that sometimes returns errors and sometimes
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// adds/removes entries on the fly. Do random operations on a DBIter and
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// check results.
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// TODO: can be improved for more coverage:
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// * Override IsKeyPinned() and IsValuePinned() to actually use
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// PinnedIteratorManager and check that there's no use-after free.
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// * Try different combinations of prefix_extractor, total_order_seek,
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// prefix_same_as_start, iterate_lower_bound, iterate_upper_bound.
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TEST_F(DBIteratorStressTest, StressTest) {
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// We use a deterministic RNG, and everything happens in a single thread.
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Random64 rnd(826909345792864532ll);
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auto gen_key = [&](int max_key) {
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assert(max_key > 0);
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int len = 0;
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int a = max_key;
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while (a) {
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a /= 10;
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++len;
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}
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std::string s = ToString(rnd.Next() % static_cast<uint64_t>(max_key));
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s.insert(0, len - (int)s.size(), '0');
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return s;
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};
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Options options;
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options.merge_operator = MergeOperators::CreateFromStringId("stringappend");
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ReadOptions ropt;
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size_t num_matching = 0;
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size_t num_at_end = 0;
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size_t num_not_ok = 0;
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size_t num_recently_removed = 0;
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// Number of iterations for each combination of parameters
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// (there are ~250 of those).
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// Tweak this to change the test run time.
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// As of the time of writing, the test takes ~4 seconds for value of 5000.
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const int num_iterations = 5000;
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// Enable this to print all the operations for debugging.
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bool trace = FLAGS_verbose;
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for (int num_entries : {5, 10, 100}) {
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for (double key_space : {0.1, 1.0, 3.0}) {
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for (ValueType prevalent_entry_type :
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{kTypeValue, kTypeDeletion, kTypeMerge}) {
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for (double error_probability : {0.01, 0.1}) {
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for (double mutation_probability : {0.01, 0.5}) {
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for (double target_hidden_fraction : {0.1, 0.5}) {
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std::string trace_str =
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"entries: " + ToString(num_entries) +
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", key_space: " + ToString(key_space) +
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", error_probability: " + ToString(error_probability) +
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", mutation_probability: " + ToString(mutation_probability) +
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", target_hidden_fraction: " +
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ToString(target_hidden_fraction);
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SCOPED_TRACE(trace_str);
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if (trace) {
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std::cout << trace_str << std::endl;
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}
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// Generate data.
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Data data;
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int max_key = (int)(num_entries * key_space) + 1;
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for (int i = 0; i < num_entries; ++i) {
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Entry e;
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e.key = gen_key(max_key);
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if (rnd.Next() % 10 != 0) {
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e.type = prevalent_entry_type;
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} else {
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const ValueType types[] = {kTypeValue, kTypeDeletion,
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kTypeMerge};
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e.type =
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types[rnd.Next() % (sizeof(types) / sizeof(types[0]))];
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}
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e.sequence = i;
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e.value = "v" + ToString(i);
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ParsedInternalKey internal_key(e.key, e.sequence, e.type);
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AppendInternalKey(&e.ikey, internal_key);
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data.entries.push_back(e);
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}
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std::sort(data.entries.begin(), data.entries.end());
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if (trace) {
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std::cout << "entries:";
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for (size_t i = 0; i < data.entries.size(); ++i) {
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Entry& e = data.entries[i];
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std::cout
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<< "\n idx " << i << ": \"" << e.key << "\": \""
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<< e.value << "\" seq: " << e.sequence << " type: "
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<< (e.type == kTypeValue
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? "val"
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: e.type == kTypeDeletion ? "del" : "merge");
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}
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std::cout << std::endl;
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}
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std::unique_ptr<Iterator> db_iter;
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std::unique_ptr<ReferenceIterator> ref_iter;
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for (int iteration = 0; iteration < num_iterations; ++iteration) {
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SCOPED_TRACE(iteration);
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// Create a new iterator every ~30 operations.
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if (db_iter == nullptr || rnd.Next() % 30 == 0) {
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uint64_t sequence = rnd.Next() % (data.entries.size() + 2);
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ref_iter.reset(new ReferenceIterator(&data, sequence));
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if (trace) {
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std::cout << "new iterator, seq: " << sequence << std::endl;
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}
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auto internal_iter =
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new StressTestIterator(&data, &rnd, BytewiseComparator());
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internal_iter->error_probability = error_probability;
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internal_iter->mutation_probability = mutation_probability;
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internal_iter->target_hidden_fraction =
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target_hidden_fraction;
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internal_iter->trace = trace;
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db_iter.reset(NewDBIterator(
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env_, ropt, ImmutableCFOptions(options),
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MutableCFOptions(options), BytewiseComparator(),
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internal_iter, sequence,
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options.max_sequential_skip_in_iterations,
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nullptr /*read_callback*/));
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}
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// Do a random operation. It's important to do it on ref_it
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// later than on db_iter to make sure ref_it sees the correct
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// recently_touched_keys.
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std::string old_key;
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bool forward = rnd.Next() % 2 > 0;
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// Do Next()/Prev() ~90% of the time.
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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
|
|
|
|
int main(int argc, char** argv) {
|
|
::testing::InitGoogleTest(&argc, argv);
|
|
ParseCommandLineFlags(&argc, &argv, true);
|
|
return RUN_ALL_TESTS();
|
|
}
|