Пример #1
0
  @Test
  public void testRecoveryDiff() throws IOException, InterruptedException {
    int numDocs = 2 + random().nextInt(100);
    List<Document> docs = new ArrayList<>();
    for (int i = 0; i < numDocs; i++) {
      Document doc = new Document();
      doc.add(
          new StringField("id", "" + i, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new TextField(
              "body",
              TestUtil.randomRealisticUnicodeString(random()),
              random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new SortedDocValuesField(
              "dv", new BytesRef(TestUtil.randomRealisticUnicodeString(random()))));
      docs.add(doc);
    }
    long seed = random().nextLong();
    Store.MetadataSnapshot first;
    {
      Random random = new Random(seed);
      IndexWriterConfig iwc =
          new IndexWriterConfig(new MockAnalyzer(random)).setCodec(actualDefaultCodec());
      iwc.setMergePolicy(NoMergePolicy.INSTANCE);
      iwc.setUseCompoundFile(random.nextBoolean());
      iwc.setMaxThreadStates(1);
      final ShardId shardId = new ShardId(new Index("index"), 1);
      DirectoryService directoryService = new LuceneManagedDirectoryService(random);
      Store store =
          new Store(
              shardId,
              ImmutableSettings.EMPTY,
              directoryService,
              randomDistributor(random, directoryService),
              new DummyShardLock(shardId));
      IndexWriter writer = new IndexWriter(store.directory(), iwc);
      final boolean lotsOfSegments = rarely(random);
      for (Document d : docs) {
        writer.addDocument(d);
        if (lotsOfSegments && random.nextBoolean()) {
          writer.commit();
        } else if (rarely(random)) {
          writer.commit();
        }
      }
      writer.commit();
      writer.close();
      first = store.getMetadata();
      assertDeleteContent(store, directoryService);
      store.close();
    }
    long time = new Date().getTime();
    while (time == new Date().getTime()) {
      Thread.sleep(10); // bump the time
    }
    Store.MetadataSnapshot second;
    Store store;
    {
      Random random = new Random(seed);
      IndexWriterConfig iwc =
          new IndexWriterConfig(new MockAnalyzer(random)).setCodec(actualDefaultCodec());
      iwc.setMergePolicy(NoMergePolicy.INSTANCE);
      iwc.setUseCompoundFile(random.nextBoolean());
      iwc.setMaxThreadStates(1);
      final ShardId shardId = new ShardId(new Index("index"), 1);
      DirectoryService directoryService = new LuceneManagedDirectoryService(random);
      store =
          new Store(
              shardId,
              ImmutableSettings.EMPTY,
              directoryService,
              randomDistributor(random, directoryService),
              new DummyShardLock(shardId));
      IndexWriter writer = new IndexWriter(store.directory(), iwc);
      final boolean lotsOfSegments = rarely(random);
      for (Document d : docs) {
        writer.addDocument(d);
        if (lotsOfSegments && random.nextBoolean()) {
          writer.commit();
        } else if (rarely(random)) {
          writer.commit();
        }
      }
      writer.commit();
      writer.close();
      second = store.getMetadata();
    }
    Store.RecoveryDiff diff = first.recoveryDiff(second);
    assertThat(first.size(), equalTo(second.size()));
    for (StoreFileMetaData md : first) {
      assertThat(second.get(md.name()), notNullValue());
      // si files are different - containing timestamps etc
      assertThat(second.get(md.name()).isSame(md), equalTo(false));
    }
    assertThat(diff.different.size(), equalTo(first.size()));
    assertThat(
        diff.identical.size(),
        equalTo(0)); // in lucene 5 nothing is identical - we use random ids in file headers
    assertThat(diff.missing, empty());

    // check the self diff
    Store.RecoveryDiff selfDiff = first.recoveryDiff(first);
    assertThat(selfDiff.identical.size(), equalTo(first.size()));
    assertThat(selfDiff.different, empty());
    assertThat(selfDiff.missing, empty());

    // lets add some deletes
    Random random = new Random(seed);
    IndexWriterConfig iwc =
        new IndexWriterConfig(new MockAnalyzer(random)).setCodec(actualDefaultCodec());
    iwc.setMergePolicy(NoMergePolicy.INSTANCE);
    iwc.setUseCompoundFile(random.nextBoolean());
    iwc.setMaxThreadStates(1);
    iwc.setOpenMode(IndexWriterConfig.OpenMode.APPEND);
    IndexWriter writer = new IndexWriter(store.directory(), iwc);
    writer.deleteDocuments(new Term("id", Integer.toString(random().nextInt(numDocs))));
    writer.commit();
    writer.close();
    Store.MetadataSnapshot metadata = store.getMetadata();
    StoreFileMetaData delFile = null;
    for (StoreFileMetaData md : metadata) {
      if (md.name().endsWith(".liv")) {
        delFile = md;
        break;
      }
    }
    Store.RecoveryDiff afterDeleteDiff = metadata.recoveryDiff(second);
    if (delFile != null) {
      assertThat(
          afterDeleteDiff.identical.size(), equalTo(metadata.size() - 2)); // segments_N + del file
      assertThat(afterDeleteDiff.different.size(), equalTo(0));
      assertThat(afterDeleteDiff.missing.size(), equalTo(2));
    } else {
      // an entire segment must be missing (single doc segment got dropped)
      assertThat(afterDeleteDiff.identical.size(), greaterThan(0));
      assertThat(afterDeleteDiff.different.size(), equalTo(0));
      assertThat(afterDeleteDiff.missing.size(), equalTo(1)); // the commit file is different
    }

    // check the self diff
    selfDiff = metadata.recoveryDiff(metadata);
    assertThat(selfDiff.identical.size(), equalTo(metadata.size()));
    assertThat(selfDiff.different, empty());
    assertThat(selfDiff.missing, empty());

    // add a new commit
    iwc = new IndexWriterConfig(new MockAnalyzer(random)).setCodec(actualDefaultCodec());
    iwc.setMergePolicy(NoMergePolicy.INSTANCE);
    iwc.setUseCompoundFile(
        true); // force CFS - easier to test here since we know it will add 3 files
    iwc.setMaxThreadStates(1);
    iwc.setOpenMode(IndexWriterConfig.OpenMode.APPEND);
    writer = new IndexWriter(store.directory(), iwc);
    writer.addDocument(docs.get(0));
    writer.close();

    Store.MetadataSnapshot newCommitMetaData = store.getMetadata();
    Store.RecoveryDiff newCommitDiff = newCommitMetaData.recoveryDiff(metadata);
    if (delFile != null) {
      assertThat(
          newCommitDiff.identical.size(),
          equalTo(
              newCommitMetaData.size()
                  - 5)); // segments_N, del file, cfs, cfe, si for the new segment
      assertThat(newCommitDiff.different.size(), equalTo(1)); // the del file must be different
      assertThat(newCommitDiff.different.get(0).name(), endsWith(".liv"));
      assertThat(
          newCommitDiff.missing.size(), equalTo(4)); // segments_N,cfs, cfe, si for the new segment
    } else {
      assertThat(
          newCommitDiff.identical.size(),
          equalTo(newCommitMetaData.size() - 4)); // segments_N, cfs, cfe, si for the new segment
      assertThat(newCommitDiff.different.size(), equalTo(0));
      assertThat(
          newCommitDiff.missing.size(),
          equalTo(
              4)); // an entire segment must be missing (single doc segment got dropped)  plus the
                   // commit is different
    }

    store.deleteContent();
    IOUtils.close(store);
  }
Пример #2
0
  @Test
  public void testMixedChecksums() throws IOException {
    final ShardId shardId = new ShardId(new Index("index"), 1);
    DirectoryService directoryService = new LuceneManagedDirectoryService(random());
    Store store =
        new Store(
            shardId,
            ImmutableSettings.EMPTY,
            directoryService,
            randomDistributor(directoryService),
            new DummyShardLock(shardId));
    // this time random codec....
    IndexWriter writer =
        new IndexWriter(
            store.directory(),
            newIndexWriterConfig(random(), new MockAnalyzer(random()))
                .setCodec(actualDefaultCodec()));
    int docs = 1 + random().nextInt(100);

    for (int i = 0; i < docs; i++) {
      Document doc = new Document();
      doc.add(
          new TextField("id", "" + i, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new TextField(
              "body",
              TestUtil.randomRealisticUnicodeString(random()),
              random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new SortedDocValuesField(
              "dv", new BytesRef(TestUtil.randomRealisticUnicodeString(random()))));
      writer.addDocument(doc);
    }
    if (random().nextBoolean()) {
      for (int i = 0; i < docs; i++) {
        if (random().nextBoolean()) {
          Document doc = new Document();
          doc.add(
              new TextField(
                  "id", "" + i, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
          doc.add(
              new TextField(
                  "body",
                  TestUtil.randomRealisticUnicodeString(random()),
                  random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
          writer.updateDocument(new Term("id", "" + i), doc);
        }
      }
    }
    if (random().nextBoolean()) {
      DirectoryReader.open(writer, random().nextBoolean()).close(); // flush
    }
    Store.MetadataSnapshot metadata;
    // check before we committed
    try {
      store.getMetadata();
      fail("no index present - expected exception");
    } catch (IndexNotFoundException ex) {
      // expected
    }
    assertThat(store.getMetadataOrEmpty(), is(Store.MetadataSnapshot.EMPTY)); // nothing committed
    writer.commit();
    writer.close();
    Store.LegacyChecksums checksums = new Store.LegacyChecksums();
    metadata = store.getMetadata();
    assertThat(metadata.asMap().isEmpty(), is(false));
    for (StoreFileMetaData meta : metadata) {
      try (IndexInput input = store.directory().openInput(meta.name(), IOContext.DEFAULT)) {
        if (meta.checksum() == null) {
          String checksum = null;
          try {
            CodecUtil.retrieveChecksum(input);
            fail("expected a corrupt index - posting format has not checksums");
          } catch (CorruptIndexException
              | IndexFormatTooOldException
              | IndexFormatTooNewException ex) {
            try (ChecksumIndexInput checksumIndexInput =
                store.directory().openChecksumInput(meta.name(), IOContext.DEFAULT)) {
              checksumIndexInput.seek(meta.length());
              checksum = Store.digestToString(checksumIndexInput.getChecksum());
            }
            // fine - it's a postings format without checksums
            checksums.add(new StoreFileMetaData(meta.name(), meta.length(), checksum, null));
          }
        } else {
          String checksum = Store.digestToString(CodecUtil.retrieveChecksum(input));
          assertThat(
              "File: " + meta.name() + " has a different checksum",
              meta.checksum(),
              equalTo(checksum));
          assertThat(meta.hasLegacyChecksum(), equalTo(false));
          assertThat(meta.writtenBy(), equalTo(Version.LATEST));
        }
      }
    }
    assertConsistent(store, metadata);
    checksums.write(store);
    metadata = store.getMetadata();
    assertThat(metadata.asMap().isEmpty(), is(false));
    for (StoreFileMetaData meta : metadata) {
      assertThat(
          "file: " + meta.name() + " has a null checksum", meta.checksum(), not(nullValue()));
      if (meta.hasLegacyChecksum()) {
        try (ChecksumIndexInput checksumIndexInput =
            store.directory().openChecksumInput(meta.name(), IOContext.DEFAULT)) {
          checksumIndexInput.seek(meta.length());
          assertThat(
              meta.checksum(), equalTo(Store.digestToString(checksumIndexInput.getChecksum())));
        }
      } else {
        try (IndexInput input = store.directory().openInput(meta.name(), IOContext.DEFAULT)) {
          String checksum = Store.digestToString(CodecUtil.retrieveChecksum(input));
          assertThat(
              "File: " + meta.name() + " has a different checksum",
              meta.checksum(),
              equalTo(checksum));
          assertThat(meta.hasLegacyChecksum(), equalTo(false));
          assertThat(meta.writtenBy(), equalTo(Version.LATEST));
        }
      }
    }
    assertConsistent(store, metadata);
    TestUtil.checkIndex(store.directory());
    assertDeleteContent(store, directoryService);
    IOUtils.close(store);
  }
Пример #3
0
  // IF THIS TEST FAILS ON UPGRADE GO LOOK AT THE
  // OldSIMockingCodec!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  @Test
  public void testWriteLegacyChecksums() throws IOException {
    final ShardId shardId = new ShardId(new Index("index"), 1);
    DirectoryService directoryService = new LuceneManagedDirectoryService(random());
    Store store =
        new Store(
            shardId,
            ImmutableSettings.EMPTY,
            directoryService,
            randomDistributor(directoryService),
            new DummyShardLock(shardId));
    // set default codec - all segments need checksums
    final boolean usesOldCodec = randomBoolean();
    IndexWriter writer =
        new IndexWriter(
            store.directory(),
            newIndexWriterConfig(random(), new MockAnalyzer(random()))
                .setCodec(usesOldCodec ? new OldSIMockingCodec() : actualDefaultCodec()));
    int docs = 1 + random().nextInt(100);

    for (int i = 0; i < docs; i++) {
      Document doc = new Document();
      doc.add(
          new TextField("id", "" + i, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new TextField(
              "body",
              TestUtil.randomRealisticUnicodeString(random()),
              random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new SortedDocValuesField(
              "dv", new BytesRef(TestUtil.randomRealisticUnicodeString(random()))));
      writer.addDocument(doc);
    }
    if (random().nextBoolean()) {
      for (int i = 0; i < docs; i++) {
        if (random().nextBoolean()) {
          Document doc = new Document();
          doc.add(
              new TextField(
                  "id", "" + i, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
          doc.add(
              new TextField(
                  "body",
                  TestUtil.randomRealisticUnicodeString(random()),
                  random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
          writer.updateDocument(new Term("id", "" + i), doc);
        }
      }
    }
    if (random().nextBoolean()) {
      DirectoryReader.open(writer, random().nextBoolean()).close(); // flush
    }
    Store.MetadataSnapshot metadata;
    // check before we committed
    try {
      store.getMetadata();
      fail("no index present - expected exception");
    } catch (IndexNotFoundException ex) {
      // expected
    }
    assertThat(store.getMetadataOrEmpty(), is(Store.MetadataSnapshot.EMPTY)); // nothing committed

    writer.close();
    Store.LegacyChecksums checksums = new Store.LegacyChecksums();
    Map<String, StoreFileMetaData> legacyMeta = new HashMap<>();
    for (String file : store.directory().listAll()) {
      if (file.equals("write.lock") || file.equals(IndexFileNames.OLD_SEGMENTS_GEN)) {
        continue;
      }
      BytesRef hash = new BytesRef();
      if (file.startsWith("segments")) {
        hash = Store.MetadataSnapshot.hashFile(store.directory(), file);
      }
      StoreFileMetaData storeFileMetaData =
          new StoreFileMetaData(
              file, store.directory().fileLength(file), file + "checksum", null, hash);
      legacyMeta.put(file, storeFileMetaData);
      checksums.add(storeFileMetaData);
    }
    checksums.write(store);

    metadata = store.getMetadata();
    Map<String, StoreFileMetaData> stringStoreFileMetaDataMap = metadata.asMap();
    assertThat(legacyMeta.size(), equalTo(stringStoreFileMetaDataMap.size()));
    if (usesOldCodec) {
      for (StoreFileMetaData meta : legacyMeta.values()) {
        assertTrue(meta.toString(), stringStoreFileMetaDataMap.containsKey(meta.name()));
        assertEquals(meta.name() + "checksum", meta.checksum());
        assertTrue(
            meta + " vs. " + stringStoreFileMetaDataMap.get(meta.name()),
            stringStoreFileMetaDataMap.get(meta.name()).isSame(meta));
      }
    } else {

      // even if we have a legacy checksum - if we use a new codec we should reuse
      for (StoreFileMetaData meta : legacyMeta.values()) {
        assertTrue(meta.toString(), stringStoreFileMetaDataMap.containsKey(meta.name()));
        assertFalse(
            meta + " vs. " + stringStoreFileMetaDataMap.get(meta.name()),
            stringStoreFileMetaDataMap.get(meta.name()).isSame(meta));
        StoreFileMetaData storeFileMetaData = metadata.get(meta.name());
        try (IndexInput input =
            store.openVerifyingInput(meta.name(), IOContext.DEFAULT, storeFileMetaData)) {
          assertTrue(storeFileMetaData.toString(), input instanceof Store.VerifyingIndexInput);
          input.seek(meta.length());
          Store.verify(input);
        }
      }
    }
    assertDeleteContent(store, directoryService);
    IOUtils.close(store);
  }
Пример #4
0
  @Test
  public void testNewChecksums() throws IOException {
    final ShardId shardId = new ShardId(new Index("index"), 1);
    DirectoryService directoryService = new LuceneManagedDirectoryService(random());
    Store store =
        new Store(
            shardId,
            ImmutableSettings.EMPTY,
            directoryService,
            randomDistributor(directoryService),
            new DummyShardLock(shardId));
    // set default codec - all segments need checksums
    IndexWriter writer =
        new IndexWriter(
            store.directory(),
            newIndexWriterConfig(random(), new MockAnalyzer(random()))
                .setCodec(actualDefaultCodec()));
    int docs = 1 + random().nextInt(100);

    for (int i = 0; i < docs; i++) {
      Document doc = new Document();
      doc.add(
          new TextField("id", "" + i, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new TextField(
              "body",
              TestUtil.randomRealisticUnicodeString(random()),
              random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new SortedDocValuesField(
              "dv", new BytesRef(TestUtil.randomRealisticUnicodeString(random()))));
      writer.addDocument(doc);
    }
    if (random().nextBoolean()) {
      for (int i = 0; i < docs; i++) {
        if (random().nextBoolean()) {
          Document doc = new Document();
          doc.add(
              new TextField(
                  "id", "" + i, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
          doc.add(
              new TextField(
                  "body",
                  TestUtil.randomRealisticUnicodeString(random()),
                  random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
          writer.updateDocument(new Term("id", "" + i), doc);
        }
      }
    }
    if (random().nextBoolean()) {
      DirectoryReader.open(writer, random().nextBoolean()).close(); // flush
    }
    Store.MetadataSnapshot metadata;
    // check before we committed
    try {
      store.getMetadata();
      fail("no index present - expected exception");
    } catch (IndexNotFoundException ex) {
      // expected
    }
    assertThat(store.getMetadataOrEmpty(), is(Store.MetadataSnapshot.EMPTY)); // nothing committed
    writer.commit();
    writer.close();
    metadata = store.getMetadata();
    assertThat(metadata.asMap().isEmpty(), is(false));
    for (StoreFileMetaData meta : metadata) {
      try (IndexInput input = store.directory().openInput(meta.name(), IOContext.DEFAULT)) {
        String checksum = Store.digestToString(CodecUtil.retrieveChecksum(input));
        assertThat(
            "File: " + meta.name() + " has a different checksum",
            meta.checksum(),
            equalTo(checksum));
        assertThat(meta.hasLegacyChecksum(), equalTo(false));
        assertThat(meta.writtenBy(), equalTo(Version.LATEST));
        if (meta.name().endsWith(".si") || meta.name().startsWith("segments_")) {
          assertThat(meta.hash().length, greaterThan(0));
        }
      }
    }
    assertConsistent(store, metadata);

    TestUtil.checkIndex(store.directory());
    assertDeleteContent(store, directoryService);
    IOUtils.close(store);
  }
Пример #5
0
  @Test
  public void testCleanupFromSnapshot() throws IOException {
    final ShardId shardId = new ShardId(new Index("index"), 1);
    DirectoryService directoryService = new LuceneManagedDirectoryService(random());
    Store store =
        new Store(
            shardId,
            ImmutableSettings.EMPTY,
            directoryService,
            randomDistributor(directoryService),
            new DummyShardLock(shardId));
    // this time random codec....
    IndexWriterConfig indexWriterConfig =
        newIndexWriterConfig(random(), new MockAnalyzer(random())).setCodec(actualDefaultCodec());
    // we keep all commits and that allows us clean based on multiple snapshots
    indexWriterConfig.setIndexDeletionPolicy(NoDeletionPolicy.INSTANCE);
    IndexWriter writer = new IndexWriter(store.directory(), indexWriterConfig);
    int docs = 1 + random().nextInt(100);
    int numCommits = 0;
    for (int i = 0; i < docs; i++) {
      if (i > 0 && randomIntBetween(0, 10) == 0) {
        writer.commit();
        numCommits++;
      }
      Document doc = new Document();
      doc.add(
          new TextField("id", "" + i, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new TextField(
              "body",
              TestUtil.randomRealisticUnicodeString(random()),
              random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new SortedDocValuesField(
              "dv", new BytesRef(TestUtil.randomRealisticUnicodeString(random()))));
      writer.addDocument(doc);
    }
    if (numCommits < 1) {
      writer.commit();
      Document doc = new Document();
      doc.add(
          new TextField(
              "id", "" + docs++, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new TextField(
              "body",
              TestUtil.randomRealisticUnicodeString(random()),
              random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
      doc.add(
          new SortedDocValuesField(
              "dv", new BytesRef(TestUtil.randomRealisticUnicodeString(random()))));
      writer.addDocument(doc);
    }

    Store.MetadataSnapshot firstMeta = store.getMetadata();

    if (random().nextBoolean()) {
      for (int i = 0; i < docs; i++) {
        if (random().nextBoolean()) {
          Document doc = new Document();
          doc.add(
              new TextField(
                  "id", "" + i, random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
          doc.add(
              new TextField(
                  "body",
                  TestUtil.randomRealisticUnicodeString(random()),
                  random().nextBoolean() ? Field.Store.YES : Field.Store.NO));
          writer.updateDocument(new Term("id", "" + i), doc);
        }
      }
    }
    writer.commit();
    writer.close();

    Store.MetadataSnapshot secondMeta = store.getMetadata();

    Store.LegacyChecksums checksums = new Store.LegacyChecksums();
    Map<String, StoreFileMetaData> legacyMeta = new HashMap<>();
    for (String file : store.directory().listAll()) {
      if (file.equals("write.lock") || file.equals(IndexFileNames.OLD_SEGMENTS_GEN)) {
        continue;
      }
      BytesRef hash = new BytesRef();
      if (file.startsWith("segments")) {
        hash = Store.MetadataSnapshot.hashFile(store.directory(), file);
      }
      StoreFileMetaData storeFileMetaData =
          new StoreFileMetaData(
              file, store.directory().fileLength(file), file + "checksum", null, hash);
      legacyMeta.put(file, storeFileMetaData);
      checksums.add(storeFileMetaData);
    }
    checksums.write(
        store); // write one checksum file here - we expect it to survive all the cleanups

    if (randomBoolean()) {
      store.cleanupAndVerify("test", firstMeta);
      String[] strings = store.directory().listAll();
      int numChecksums = 0;
      int numNotFound = 0;
      for (String file : strings) {
        assertTrue(firstMeta.contains(file) || Store.isChecksum(file));
        if (Store.isChecksum(file)) {
          numChecksums++;
        } else if (secondMeta.contains(file) == false) {
          numNotFound++;
        }
      }
      assertTrue(
          "at least one file must not be in here since we have two commits?", numNotFound > 0);
      assertEquals(
          "we wrote one checksum but it's gone now? - checksums are supposed to be kept",
          numChecksums,
          1);
    } else {
      store.cleanupAndVerify("test", secondMeta);
      String[] strings = store.directory().listAll();
      int numChecksums = 0;
      int numNotFound = 0;
      for (String file : strings) {
        assertTrue(secondMeta.contains(file) || Store.isChecksum(file));
        if (Store.isChecksum(file)) {
          numChecksums++;
        } else if (firstMeta.contains(file) == false) {
          numNotFound++;
        }
      }
      assertTrue(
          "at least one file must not be in here since we have two commits?", numNotFound > 0);
      assertEquals(
          "we wrote one checksum but it's gone now? - checksums are supposed to be kept",
          numChecksums,
          1);
    }

    store.deleteContent();
    IOUtils.close(store);
  }