Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 654 insertions, 0 deletions

diff --git a/src/rocksdb/db/db_iter_stress_test.cc b/src/rocksdb/db/db_iter_stress_test.cc
new file mode 100644
index 00000000..a0f1dfea
--- /dev/null
+++ b/src/rocksdb/db/db_iter_stress_test.cc
@@ -0,0 +1,654 @@
+//  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 "util/random.h"
+#include "util/string_util.h"
+#include "util/testharness.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 {
+
+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() >=
+        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() >=
+        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() < 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, ImmutableCFOptions(options),
+                      MutableCFOptions(options), BytewiseComparator(),
+                      internal_iter, 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
+
+int main(int argc, char** argv) {
+  ::testing::InitGoogleTest(&argc, argv);
+  ParseCommandLineFlags(&argc, &argv, true);
+  return RUN_ALL_TESTS();
+}