Revision 0bb555630f5e85a1471843f8dc0dabec297c1c49 authored by Siying Dong on 08 April 2019, 20:24:29 UTC, committed by Facebook Github Bot on 08 April 2019, 20:32:06 UTC
Summary:
Create new function NPHash64() and GetSliceNPHash64(), which are currently
implemented using murmurhash.
Replace the current direct call of murmurhash() to use the new functions
if the hash results are not used in on-disk format.
This will make it easier to try out or switch to alternative functions
in the uses where data format compatibility doesn't need to be considered.
This part shouldn't have any performance impact.

Also, the sharded cache hash function is changed to the new format, because
it falls into this categoery. It doesn't show visible performance impact
in db_bench results. CPU showed by perf is increased from about 0.2% to 0.4%
in an extreme benchmark setting (4KB blocks, no-compression, everything
cached in block cache). We've known that the current hash function used,
our own Hash() has serious hash quality problem. It can generate a lots of
conflicts with similar input. In this use case, it means extra lock contention
for reads from the same file. This slight CPU regression is worthy to me
to counter the potential bad performance with hot keys. And hopefully this
will get further improved in the future with a better hash function.

cache_test's condition is relaxed a little bit to. The new hash is slightly
more skewed in this use case, but I manually checked the data and see
the hash results are still in a reasonable range.
Pull Request resolved: https://github.com/facebook/rocksdb/pull/5155

Differential Revision: D14834821

Pulled By: siying

fbshipit-source-id: ec9a2c0a2f8ae4b54d08b13a5c2e9cc97aa80cb5
1 parent de00f28
Raw File
repair_test.cc
//  Copyright (c) 2016-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).

#ifndef ROCKSDB_LITE

#include <algorithm>
#include <string>
#include <vector>

#include "db/db_impl.h"
#include "db/db_test_util.h"
#include "rocksdb/comparator.h"
#include "rocksdb/db.h"
#include "rocksdb/transaction_log.h"
#include "util/file_util.h"
#include "util/string_util.h"

namespace rocksdb {

#ifndef ROCKSDB_LITE
class RepairTest : public DBTestBase {
 public:
  RepairTest() : DBTestBase("/repair_test") {}

  std::string GetFirstSstPath() {
    uint64_t manifest_size;
    std::vector<std::string> files;
    db_->GetLiveFiles(files, &manifest_size);
    auto sst_iter =
        std::find_if(files.begin(), files.end(), [](const std::string& file) {
          uint64_t number;
          FileType type;
          bool ok = ParseFileName(file, &number, &type);
          return ok && type == kTableFile;
        });
    return sst_iter == files.end() ? "" : dbname_ + *sst_iter;
  }
};

TEST_F(RepairTest, LostManifest) {
  // Add a couple SST files, delete the manifest, and verify RepairDB() saves
  // the day.
  Put("key", "val");
  Flush();
  Put("key2", "val2");
  Flush();
  // Need to get path before Close() deletes db_, but delete it after Close() to
  // ensure Close() didn't change the manifest.
  std::string manifest_path =
      DescriptorFileName(dbname_, dbfull()->TEST_Current_Manifest_FileNo());

  Close();
  ASSERT_OK(env_->FileExists(manifest_path));
  ASSERT_OK(env_->DeleteFile(manifest_path));
  ASSERT_OK(RepairDB(dbname_, CurrentOptions()));
  Reopen(CurrentOptions());

  ASSERT_EQ(Get("key"), "val");
  ASSERT_EQ(Get("key2"), "val2");
}

TEST_F(RepairTest, CorruptManifest) {
  // Manifest is in an invalid format. Expect a full recovery.
  Put("key", "val");
  Flush();
  Put("key2", "val2");
  Flush();
  // Need to get path before Close() deletes db_, but overwrite it after Close()
  // to ensure Close() didn't change the manifest.
  std::string manifest_path =
      DescriptorFileName(dbname_, dbfull()->TEST_Current_Manifest_FileNo());

  Close();
  ASSERT_OK(env_->FileExists(manifest_path));
  CreateFile(env_, manifest_path, "blah", false /* use_fsync */);
  ASSERT_OK(RepairDB(dbname_, CurrentOptions()));
  Reopen(CurrentOptions());

  ASSERT_EQ(Get("key"), "val");
  ASSERT_EQ(Get("key2"), "val2");
}

TEST_F(RepairTest, IncompleteManifest) {
  // In this case, the manifest is valid but does not reference all of the SST
  // files. Expect a full recovery.
  Put("key", "val");
  Flush();
  std::string orig_manifest_path =
      DescriptorFileName(dbname_, dbfull()->TEST_Current_Manifest_FileNo());
  CopyFile(orig_manifest_path, orig_manifest_path + ".tmp");
  Put("key2", "val2");
  Flush();
  // Need to get path before Close() deletes db_, but overwrite it after Close()
  // to ensure Close() didn't change the manifest.
  std::string new_manifest_path =
      DescriptorFileName(dbname_, dbfull()->TEST_Current_Manifest_FileNo());

  Close();
  ASSERT_OK(env_->FileExists(new_manifest_path));
  // Replace the manifest with one that is only aware of the first SST file.
  CopyFile(orig_manifest_path + ".tmp", new_manifest_path);
  ASSERT_OK(RepairDB(dbname_, CurrentOptions()));
  Reopen(CurrentOptions());

  ASSERT_EQ(Get("key"), "val");
  ASSERT_EQ(Get("key2"), "val2");
}

TEST_F(RepairTest, PostRepairSstFileNumbering) {
  // Verify after a DB is repaired, new files will be assigned higher numbers
  // than old files.
  Put("key", "val");
  Flush();
  Put("key2", "val2");
  Flush();
  uint64_t pre_repair_file_num = dbfull()->TEST_Current_Next_FileNo();
  Close();

  ASSERT_OK(RepairDB(dbname_, CurrentOptions()));

  Reopen(CurrentOptions());
  uint64_t post_repair_file_num = dbfull()->TEST_Current_Next_FileNo();
  ASSERT_GE(post_repair_file_num, pre_repair_file_num);
}

TEST_F(RepairTest, LostSst) {
  // Delete one of the SST files but preserve the manifest that refers to it,
  // then verify the DB is still usable for the intact SST.
  Put("key", "val");
  Flush();
  Put("key2", "val2");
  Flush();
  auto sst_path = GetFirstSstPath();
  ASSERT_FALSE(sst_path.empty());
  ASSERT_OK(env_->DeleteFile(sst_path));

  Close();
  ASSERT_OK(RepairDB(dbname_, CurrentOptions()));
  Reopen(CurrentOptions());

  // Exactly one of the key-value pairs should be in the DB now.
  ASSERT_TRUE((Get("key") == "val") != (Get("key2") == "val2"));
}

TEST_F(RepairTest, CorruptSst) {
  // Corrupt one of the SST files but preserve the manifest that refers to it,
  // then verify the DB is still usable for the intact SST.
  Put("key", "val");
  Flush();
  Put("key2", "val2");
  Flush();
  auto sst_path = GetFirstSstPath();
  ASSERT_FALSE(sst_path.empty());
  CreateFile(env_, sst_path, "blah", false /* use_fsync */);

  Close();
  ASSERT_OK(RepairDB(dbname_, CurrentOptions()));
  Reopen(CurrentOptions());

  // Exactly one of the key-value pairs should be in the DB now.
  ASSERT_TRUE((Get("key") == "val") != (Get("key2") == "val2"));
}

TEST_F(RepairTest, UnflushedSst) {
  // This test case invokes repair while some data is unflushed, then verifies
  // that data is in the db.
  Put("key", "val");
  VectorLogPtr wal_files;
  ASSERT_OK(dbfull()->GetSortedWalFiles(wal_files));
  ASSERT_EQ(wal_files.size(), 1);
  uint64_t total_ssts_size;
  GetAllSSTFiles(&total_ssts_size);
  ASSERT_EQ(total_ssts_size, 0);
  // Need to get path before Close() deletes db_, but delete it after Close() to
  // ensure Close() didn't change the manifest.
  std::string manifest_path =
      DescriptorFileName(dbname_, dbfull()->TEST_Current_Manifest_FileNo());

  Close();
  ASSERT_OK(env_->FileExists(manifest_path));
  ASSERT_OK(env_->DeleteFile(manifest_path));
  ASSERT_OK(RepairDB(dbname_, CurrentOptions()));
  Reopen(CurrentOptions());

  ASSERT_OK(dbfull()->GetSortedWalFiles(wal_files));
  ASSERT_EQ(wal_files.size(), 0);
  GetAllSSTFiles(&total_ssts_size);
  ASSERT_GT(total_ssts_size, 0);
  ASSERT_EQ(Get("key"), "val");
}

TEST_F(RepairTest, SeparateWalDir) {
  do {
    Options options = CurrentOptions();
    DestroyAndReopen(options);
    Put("key", "val");
    Put("foo", "bar");
    VectorLogPtr wal_files;
    ASSERT_OK(dbfull()->GetSortedWalFiles(wal_files));
    ASSERT_EQ(wal_files.size(), 1);
    uint64_t total_ssts_size;
    GetAllSSTFiles(&total_ssts_size);
    ASSERT_EQ(total_ssts_size, 0);
    std::string manifest_path =
      DescriptorFileName(dbname_, dbfull()->TEST_Current_Manifest_FileNo());

    Close();
    ASSERT_OK(env_->FileExists(manifest_path));
    ASSERT_OK(env_->DeleteFile(manifest_path));
    ASSERT_OK(RepairDB(dbname_, options));

    // make sure that all WALs are converted to SSTables.
    options.wal_dir = "";

    Reopen(options);
    ASSERT_OK(dbfull()->GetSortedWalFiles(wal_files));
    ASSERT_EQ(wal_files.size(), 0);
    GetAllSSTFiles(&total_ssts_size);
    ASSERT_GT(total_ssts_size, 0);
    ASSERT_EQ(Get("key"), "val");
    ASSERT_EQ(Get("foo"), "bar");

 } while(ChangeWalOptions());
}

TEST_F(RepairTest, RepairMultipleColumnFamilies) {
  // Verify repair logic associates SST files with their original column
  // families.
  const int kNumCfs = 3;
  const int kEntriesPerCf = 2;
  DestroyAndReopen(CurrentOptions());
  CreateAndReopenWithCF({"pikachu1", "pikachu2"}, CurrentOptions());
  for (int i = 0; i < kNumCfs; ++i) {
    for (int j = 0; j < kEntriesPerCf; ++j) {
      Put(i, "key" + ToString(j), "val" + ToString(j));
      if (j == kEntriesPerCf - 1 && i == kNumCfs - 1) {
        // Leave one unflushed so we can verify WAL entries are properly
        // associated with column families.
        continue;
      }
      Flush(i);
    }
  }

  // Need to get path before Close() deletes db_, but delete it after Close() to
  // ensure Close() doesn't re-create the manifest.
  std::string manifest_path =
      DescriptorFileName(dbname_, dbfull()->TEST_Current_Manifest_FileNo());
  Close();
  ASSERT_OK(env_->FileExists(manifest_path));
  ASSERT_OK(env_->DeleteFile(manifest_path));

  ASSERT_OK(RepairDB(dbname_, CurrentOptions()));

  ReopenWithColumnFamilies({"default", "pikachu1", "pikachu2"},
                           CurrentOptions());
  for (int i = 0; i < kNumCfs; ++i) {
    for (int j = 0; j < kEntriesPerCf; ++j) {
      ASSERT_EQ(Get(i, "key" + ToString(j)), "val" + ToString(j));
    }
  }
}

TEST_F(RepairTest, RepairColumnFamilyOptions) {
  // Verify repair logic uses correct ColumnFamilyOptions when repairing a
  // database with different options for column families.
  const int kNumCfs = 2;
  const int kEntriesPerCf = 2;

  Options opts(CurrentOptions()), rev_opts(CurrentOptions());
  opts.comparator = BytewiseComparator();
  rev_opts.comparator = ReverseBytewiseComparator();

  DestroyAndReopen(opts);
  CreateColumnFamilies({"reverse"}, rev_opts);
  ReopenWithColumnFamilies({"default", "reverse"},
                           std::vector<Options>{opts, rev_opts});
  for (int i = 0; i < kNumCfs; ++i) {
    for (int j = 0; j < kEntriesPerCf; ++j) {
      Put(i, "key" + ToString(j), "val" + ToString(j));
      if (i == kNumCfs - 1 && j == kEntriesPerCf - 1) {
        // Leave one unflushed so we can verify RepairDB's flush logic
        continue;
      }
      Flush(i);
    }
  }
  Close();

  // RepairDB() records the comparator in the manifest, and DB::Open would fail
  // if a different comparator were used.
  ASSERT_OK(RepairDB(dbname_, opts, {{"default", opts}, {"reverse", rev_opts}},
                     opts /* unknown_cf_opts */));
  ASSERT_OK(TryReopenWithColumnFamilies({"default", "reverse"},
                                        std::vector<Options>{opts, rev_opts}));
  for (int i = 0; i < kNumCfs; ++i) {
    for (int j = 0; j < kEntriesPerCf; ++j) {
      ASSERT_EQ(Get(i, "key" + ToString(j)), "val" + ToString(j));
    }
  }

  // Examine table properties to verify RepairDB() used the right options when
  // converting WAL->SST
  TablePropertiesCollection fname_to_props;
  db_->GetPropertiesOfAllTables(handles_[1], &fname_to_props);
  ASSERT_EQ(fname_to_props.size(), 2U);
  for (const auto& fname_and_props : fname_to_props) {
    std::string comparator_name (
      InternalKeyComparator(rev_opts.comparator).Name());
    comparator_name = comparator_name.substr(comparator_name.find(':') + 1);
    ASSERT_EQ(comparator_name,
              fname_and_props.second->comparator_name);
  }
  Close();

  // Also check comparator when it's provided via "unknown" CF options
  ASSERT_OK(RepairDB(dbname_, opts, {{"default", opts}},
                     rev_opts /* unknown_cf_opts */));
  ASSERT_OK(TryReopenWithColumnFamilies({"default", "reverse"},
                                        std::vector<Options>{opts, rev_opts}));
  for (int i = 0; i < kNumCfs; ++i) {
    for (int j = 0; j < kEntriesPerCf; ++j) {
      ASSERT_EQ(Get(i, "key" + ToString(j)), "val" + ToString(j));
    }
  }
}

TEST_F(RepairTest, DbNameContainsTrailingSlash) {
  {
    bool tmp;
    if (env_->AreFilesSame("", "", &tmp).IsNotSupported()) {
      fprintf(stderr,
              "skipping RepairTest.DbNameContainsTrailingSlash due to "
              "unsupported Env::AreFilesSame\n");
      return;
    }
  }

  Put("key", "val");
  Flush();
  Close();

  ASSERT_OK(RepairDB(dbname_ + "/", CurrentOptions()));
  Reopen(CurrentOptions());
  ASSERT_EQ(Get("key"), "val");
}
#endif  // ROCKSDB_LITE
}  // namespace rocksdb

int main(int argc, char** argv) {
  ::testing::InitGoogleTest(&argc, argv);
  return RUN_ALL_TESTS();
}

#else
#include <stdio.h>

int main(int /*argc*/, char** /*argv*/) {
  fprintf(stderr, "SKIPPED as RepairDB is not supported in ROCKSDB_LITE\n");
  return 0;
}

#endif  // ROCKSDB_LITE
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