github.com/m3db/m3@v1.5.1-0.20231129193456-75a402aa583b/src/dbnode/persist/fs/read_write_test.go (about)

     1  // Copyright (c) 2016 Uber Technologies, Inc.
     2  //
     3  // Permission is hereby granted, free of charge, to any person obtaining a copy
     4  // of this software and associated documentation files (the "Software"), to deal
     5  // in the Software without restriction, including without limitation the rights
     6  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
     7  // copies of the Software, and to permit persons to whom the Software is
     8  // furnished to do so, subject to the following conditions:
     9  //
    10  // The above copyright notice and this permission notice shall be included in
    11  // all copies or substantial portions of the Software.
    12  //
    13  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    14  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    15  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    16  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    17  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    18  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    19  // THE SOFTWARE.
    20  
    21  package fs
    22  
    23  import (
    24  	"bytes"
    25  	"errors"
    26  	"os"
    27  	"path/filepath"
    28  	"sort"
    29  	"testing"
    30  	"time"
    31  
    32  	"github.com/m3db/m3/src/dbnode/digest"
    33  	"github.com/m3db/m3/src/dbnode/persist"
    34  	"github.com/m3db/m3/src/dbnode/ts"
    35  	"github.com/m3db/m3/src/x/checked"
    36  	"github.com/m3db/m3/src/x/ident"
    37  	xtime "github.com/m3db/m3/src/x/time"
    38  
    39  	"github.com/m3db/bloom/v4"
    40  	"github.com/pborman/uuid"
    41  	"github.com/stretchr/testify/assert"
    42  	"github.com/stretchr/testify/require"
    43  )
    44  
    45  var (
    46  	testSnapshotID = uuid.Parse("bbc85a98-bd0c-47fe-8b9a-89cde1b4540f")
    47  )
    48  
    49  type testEntry struct {
    50  	id   string
    51  	tags map[string]string
    52  	data []byte
    53  }
    54  
    55  func (e testEntry) ID() ident.ID {
    56  	return ident.StringID(e.id)
    57  }
    58  
    59  func (e testEntry) Tags() ident.Tags {
    60  	if e.tags == nil {
    61  		return ident.Tags{}
    62  	}
    63  
    64  	// Return in sorted order for deterministic order
    65  	var keys []string
    66  	for key := range e.tags {
    67  		keys = append(keys, key)
    68  	}
    69  	sort.Strings(keys)
    70  
    71  	var tags ident.Tags
    72  	for _, key := range keys {
    73  		tags.Append(ident.StringTag(key, e.tags[key]))
    74  	}
    75  
    76  	return tags
    77  }
    78  
    79  type testEntries []testEntry
    80  
    81  func (e testEntries) Less(i, j int) bool {
    82  	return e[i].id < e[j].id
    83  }
    84  
    85  func (e testEntries) Len() int {
    86  	return len(e)
    87  }
    88  
    89  func (e testEntries) Swap(i, j int) {
    90  	e[i], e[j] = e[j], e[i]
    91  }
    92  
    93  func newTestWriter(t *testing.T, filePathPrefix string) DataFileSetWriter {
    94  	writer, err := NewWriter(testDefaultOpts.
    95  		SetFilePathPrefix(filePathPrefix).
    96  		SetWriterBufferSize(testWriterBufferSize))
    97  	require.NoError(t, err)
    98  	return writer
    99  }
   100  
   101  func writeTestData(
   102  	t *testing.T,
   103  	w DataFileSetWriter,
   104  	shard uint32,
   105  	timestamp xtime.UnixNano,
   106  	entries []testEntry,
   107  	fileSetType persist.FileSetType,
   108  ) {
   109  	writeTestDataWithVolume(
   110  		t, w, shard, timestamp, 0, entries, fileSetType)
   111  }
   112  
   113  func writeTestDataWithVolume(
   114  	t *testing.T,
   115  	w DataFileSetWriter,
   116  	shard uint32,
   117  	timestamp xtime.UnixNano,
   118  	volume int,
   119  	entries []testEntry,
   120  	fileSetType persist.FileSetType,
   121  ) {
   122  	writerOpts := DataWriterOpenOptions{
   123  		Identifier: FileSetFileIdentifier{
   124  			Namespace:   testNs1ID,
   125  			Shard:       shard,
   126  			BlockStart:  timestamp,
   127  			VolumeIndex: volume,
   128  		},
   129  		BlockSize:   testBlockSize,
   130  		FileSetType: fileSetType,
   131  	}
   132  
   133  	if fileSetType == persist.FileSetSnapshotType {
   134  		writerOpts.Snapshot.SnapshotTime = timestamp
   135  		writerOpts.Snapshot.SnapshotID = testSnapshotID
   136  	}
   137  
   138  	err := w.Open(writerOpts)
   139  	assert.NoError(t, err)
   140  
   141  	for i := range entries {
   142  		metadata := persist.NewMetadataFromIDAndTags(entries[i].ID(),
   143  			entries[i].Tags(),
   144  			persist.MetadataOptions{})
   145  		assert.NoError(t, w.Write(metadata,
   146  			bytesRefd(entries[i].data),
   147  			digest.Checksum(entries[i].data)))
   148  	}
   149  	assert.NoError(t, w.Close())
   150  
   151  	// Assert that any index entries released references they held
   152  	writer, ok := w.(*writer)
   153  	require.True(t, ok)
   154  
   155  	// Take ref to wholly allocated index entries slice
   156  	slice := writer.indexEntries[:cap(writer.indexEntries)]
   157  
   158  	// Check every entry has ID and Tags nil
   159  	for _, elem := range slice {
   160  		assert.Equal(t, persist.Metadata{}, elem.metadata)
   161  	}
   162  }
   163  
   164  type readTestType uint
   165  
   166  const (
   167  	readTestTypeData readTestType = iota
   168  	readTestTypeMetadata
   169  )
   170  
   171  var readTestTypes = []readTestType{
   172  	readTestTypeData,
   173  	readTestTypeMetadata,
   174  }
   175  
   176  //nolint: unparam
   177  func readTestData(t *testing.T, r DataFileSetReader, shard uint32,
   178  	timestamp xtime.UnixNano, entries []testEntry) {
   179  	readTestDataWithStreamingOpt(t, r, shard, timestamp, entries, false)
   180  
   181  	sortedEntries := append(make(testEntries, 0, len(entries)), entries...)
   182  	sort.Sort(sortedEntries)
   183  
   184  	readTestDataWithStreamingOpt(t, r, shard, timestamp, sortedEntries, true)
   185  }
   186  
   187  // readTestDataWithStreamingOpt will test reading back the data matches what was written,
   188  // note that this test also tests reuse of the reader since it first reads
   189  // all the data then closes it, reopens and reads through again but just
   190  // reading the metadata the second time.
   191  // If it starts to fail during the pass that reads just the metadata it could
   192  // be a newly introduced reader reuse bug.
   193  func readTestDataWithStreamingOpt(
   194  	t *testing.T,
   195  	r DataFileSetReader,
   196  	shard uint32,
   197  	timestamp xtime.UnixNano,
   198  	entries []testEntry,
   199  	streamingEnabled bool,
   200  ) {
   201  	for _, underTest := range readTestTypes {
   202  		rOpenOpts := DataReaderOpenOptions{
   203  			Identifier: FileSetFileIdentifier{
   204  				Namespace:  testNs1ID,
   205  				Shard:      shard,
   206  				BlockStart: timestamp,
   207  			},
   208  			StreamingEnabled: streamingEnabled,
   209  		}
   210  		err := r.Open(rOpenOpts)
   211  		require.NoError(t, err)
   212  
   213  		require.Equal(t, len(entries), r.Entries())
   214  		require.Equal(t, 0, r.EntriesRead())
   215  
   216  		bloomFilter, err := r.ReadBloomFilter()
   217  		assert.NoError(t, err)
   218  		// Make sure the bloom filter doesn't always return true
   219  		assert.False(t, bloomFilter.Test([]byte("some_random_data")))
   220  
   221  		expectedEntries := uint(len(entries))
   222  		if expectedEntries == 0 {
   223  			expectedEntries = 1
   224  		}
   225  		expectedM, expectedK := bloom.EstimateFalsePositiveRate(
   226  			expectedEntries, defaultIndexBloomFilterFalsePositivePercent)
   227  		assert.Equal(t, expectedK, bloomFilter.K())
   228  		// EstimateFalsePositiveRate always returns at least 1, so skip this check
   229  		// if len entries is 0
   230  		if len(entries) > 0 {
   231  			assert.Equal(t, expectedM, bloomFilter.M())
   232  		}
   233  
   234  		for i := 0; i < r.Entries(); i++ {
   235  			switch underTest {
   236  			case readTestTypeData:
   237  				id, tags, data, checksum, err := readData(t, r)
   238  				require.NoError(t, err)
   239  
   240  				data.IncRef()
   241  
   242  				// Assert id
   243  				assert.Equal(t, entries[i].id, id.String())
   244  
   245  				// Assert tags
   246  				tagMatcher := ident.NewTagIterMatcher(ident.NewTagsIterator(entries[i].Tags()))
   247  				assert.True(t, tagMatcher.Matches(tags))
   248  
   249  				assert.True(t, bytes.Equal(entries[i].data, data.Bytes()))
   250  				assert.Equal(t, digest.Checksum(entries[i].data), checksum)
   251  
   252  				assert.Equal(t, i+1, r.EntriesRead())
   253  
   254  				// Verify that the bloomFilter was bootstrapped properly by making sure it
   255  				// at least contains every ID
   256  				assert.True(t, bloomFilter.Test(id.Bytes()))
   257  
   258  				id.Finalize()
   259  				tags.Close()
   260  				data.DecRef()
   261  				data.Finalize()
   262  
   263  			case readTestTypeMetadata:
   264  				id, tags, length, checksum, err := readMetadata(t, r)
   265  				require.NoError(t, err)
   266  
   267  				// Assert id
   268  				assert.True(t, id.Equal(id))
   269  
   270  				// Assert tags
   271  				tagMatcher := ident.NewTagIterMatcher(ident.NewTagsIterator(entries[i].Tags()))
   272  				assert.True(t, tagMatcher.Matches(tags))
   273  
   274  				assert.Equal(t, digest.Checksum(entries[i].data), checksum)
   275  				assert.Equal(t, len(entries[i].data), length)
   276  
   277  				assert.Equal(t, i+1, r.MetadataRead())
   278  
   279  				// Verify that the bloomFilter was bootstrapped properly by making sure it
   280  				// at least contains every ID
   281  				assert.True(t, bloomFilter.Test(id.Bytes()))
   282  
   283  				id.Finalize()
   284  				tags.Close()
   285  			}
   286  		}
   287  
   288  		require.NoError(t, r.Close())
   289  	}
   290  }
   291  
   292  func TestSimpleReadWrite(t *testing.T) {
   293  	dir := createTempDir(t)
   294  	filePathPrefix := filepath.Join(dir, "")
   295  	defer os.RemoveAll(dir)
   296  
   297  	entries := []testEntry{
   298  		{"foo", nil, []byte{1, 2, 3}},
   299  		{"bar", nil, []byte{4, 5, 6}},
   300  		{"baz", nil, make([]byte, 65536)},
   301  		{"cat", nil, make([]byte, 100000)},
   302  		{"foo+bar=baz,qux=qaz", map[string]string{
   303  			"bar": "baz",
   304  			"qux": "qaz",
   305  		}, []byte{7, 8, 9}},
   306  	}
   307  
   308  	w := newTestWriter(t, filePathPrefix)
   309  	writeTestData(t, w, 0, testWriterStart, entries, persist.FileSetFlushType)
   310  
   311  	r := newTestReader(t, filePathPrefix)
   312  	readTestData(t, r, 0, testWriterStart, entries)
   313  }
   314  
   315  func TestCheckpointFileSizeBytesSize(t *testing.T) {
   316  	// These values need to match so that the logic for determining whether
   317  	// a checkpoint file is complete or not remains correct.
   318  	require.Equal(t, digest.DigestLenBytes, CheckpointFileSizeBytes)
   319  }
   320  
   321  func TestDuplicateWrite(t *testing.T) {
   322  	dir := createTempDir(t)
   323  	filePathPrefix := filepath.Join(dir, "")
   324  	defer os.RemoveAll(dir)
   325  
   326  	entries := []testEntry{
   327  		{"foo", nil, []byte{1, 2, 3}},
   328  		{"foo", nil, []byte{4, 5, 6}},
   329  	}
   330  
   331  	w := newTestWriter(t, filePathPrefix)
   332  	writerOpts := DataWriterOpenOptions{
   333  		Identifier: FileSetFileIdentifier{
   334  			Namespace:  testNs1ID,
   335  			Shard:      0,
   336  			BlockStart: testWriterStart,
   337  		},
   338  		BlockSize: testBlockSize,
   339  	}
   340  	err := w.Open(writerOpts)
   341  	require.NoError(t, err)
   342  
   343  	for i := range entries {
   344  		metadata := persist.NewMetadataFromIDAndTags(entries[i].ID(),
   345  			entries[i].Tags(),
   346  			persist.MetadataOptions{})
   347  		require.NoError(t, w.Write(metadata,
   348  			bytesRefd(entries[i].data),
   349  			digest.Checksum(entries[i].data)))
   350  	}
   351  	require.Equal(t, errors.New("encountered duplicate ID: foo"), w.Close())
   352  }
   353  
   354  func TestReadWithReusedReader(t *testing.T) {
   355  	dir := createTempDir(t)
   356  	filePathPrefix := filepath.Join(dir, "")
   357  	defer os.RemoveAll(dir)
   358  
   359  	entries := []testEntry{
   360  		{"foo", nil, []byte{1, 2, 3}},
   361  		{"bar", nil, []byte{4, 5, 6}},
   362  		{"baz", nil, make([]byte, 65536)},
   363  		{"cat", nil, make([]byte, 100000)},
   364  		{"foo+bar=baz,qux=qaz", map[string]string{
   365  			"bar": "baz",
   366  			"qux": "qaz",
   367  		}, []byte{7, 8, 9}},
   368  	}
   369  
   370  	w := newTestWriter(t, filePathPrefix)
   371  	writeTestData(t, w, 0, testWriterStart, entries, persist.FileSetFlushType)
   372  
   373  	r := newTestReader(t, filePathPrefix)
   374  	readTestData(t, r, 0, testWriterStart, entries)
   375  	// Reuse the reader to read again
   376  	readTestData(t, r, 0, testWriterStart, entries)
   377  }
   378  
   379  func TestInfoReadWrite(t *testing.T) {
   380  	dir := createTempDir(t)
   381  	filePathPrefix := filepath.Join(dir, "")
   382  	defer os.RemoveAll(dir)
   383  
   384  	entries := []testEntry{
   385  		{"foo", nil, []byte{1, 2, 3}},
   386  		{"bar", nil, []byte{4, 5, 6}},
   387  		{"baz", nil, make([]byte, 65536)},
   388  		{"cat", nil, make([]byte, 100000)},
   389  		{"foo+bar=baz,qux=qaz", map[string]string{
   390  			"bar": "baz",
   391  			"qux": "qaz",
   392  		}, []byte{7, 8, 9}},
   393  	}
   394  
   395  	w := newTestWriter(t, filePathPrefix)
   396  	writeTestData(t, w, 0, testWriterStart, entries, persist.FileSetFlushType)
   397  
   398  	readInfoFileResults := ReadInfoFiles(filePathPrefix, testNs1ID, 0, 16, nil, persist.FileSetFlushType)
   399  	require.Equal(t, 1, len(readInfoFileResults))
   400  	for _, result := range readInfoFileResults {
   401  		require.NoError(t, result.Err.Error())
   402  	}
   403  
   404  	infoFile := readInfoFileResults[0].Info
   405  	require.Equal(t, int64(testWriterStart), infoFile.BlockStart)
   406  	require.Equal(t, testBlockSize, time.Duration(infoFile.BlockSize))
   407  	require.Equal(t, int64(len(entries)), infoFile.Entries)
   408  }
   409  
   410  func TestInfoReadWriteVolumeIndex(t *testing.T) {
   411  	dir := createTempDir(t)
   412  	filePathPrefix := filepath.Join(dir, "")
   413  	defer os.RemoveAll(dir)
   414  
   415  	var (
   416  		entries = []testEntry{}
   417  		w       = newTestWriter(t, filePathPrefix)
   418  		volume  = 1
   419  	)
   420  
   421  	writeTestDataWithVolume(t, w, 0, testWriterStart, volume, entries, persist.FileSetFlushType)
   422  
   423  	readInfoFileResults := ReadInfoFiles(filePathPrefix, testNs1ID, 0, 16, nil, persist.FileSetFlushType)
   424  	require.Equal(t, 1, len(readInfoFileResults))
   425  	for _, result := range readInfoFileResults {
   426  		require.NoError(t, result.Err.Error())
   427  	}
   428  
   429  	infoFile := readInfoFileResults[0].Info
   430  	require.Equal(t, testWriterStart, xtime.UnixNano(infoFile.BlockStart))
   431  	require.Equal(t, volume, infoFile.VolumeIndex)
   432  	require.Equal(t, testBlockSize, time.Duration(infoFile.BlockSize))
   433  	require.Equal(t, int64(len(entries)), infoFile.Entries)
   434  }
   435  
   436  func TestInfoReadWriteSnapshot(t *testing.T) {
   437  	dir := createTempDir(t)
   438  	filePathPrefix := filepath.Join(dir, "")
   439  	defer os.RemoveAll(dir)
   440  
   441  	w := newTestWriter(t, filePathPrefix)
   442  	writeTestData(t, w, 0, testWriterStart, nil, persist.FileSetSnapshotType)
   443  
   444  	snapshotFiles, err := SnapshotFiles(filePathPrefix, testNs1ID, 0)
   445  	require.NoError(t, err)
   446  
   447  	require.Equal(t, 1, len(snapshotFiles))
   448  
   449  	snapshot := snapshotFiles[0]
   450  	snapshotTime, snapshotID, err := snapshot.SnapshotTimeAndID()
   451  	require.NoError(t, err)
   452  	require.True(t, testWriterStart.Equal(snapshotTime))
   453  	require.Equal(t, testSnapshotID, snapshotID)
   454  }
   455  
   456  func TestReusingReaderWriter(t *testing.T) {
   457  	dir := createTempDir(t)
   458  	filePathPrefix := filepath.Join(dir, "")
   459  	defer os.RemoveAll(dir)
   460  
   461  	allEntries := [][]testEntry{
   462  		{
   463  			{"foo", nil, []byte{1, 2, 3}},
   464  			{"bar", nil, []byte{4, 5, 6}},
   465  		},
   466  		{
   467  			{"baz", nil, []byte{7, 8, 9}},
   468  		},
   469  		{},
   470  	}
   471  	w := newTestWriter(t, filePathPrefix)
   472  	for i := range allEntries {
   473  		writeTestData(
   474  			t, w, 0, testWriterStart.Add(time.Duration(i)*time.Hour), allEntries[i], persist.FileSetFlushType)
   475  	}
   476  
   477  	r := newTestReader(t, filePathPrefix)
   478  	for i := range allEntries {
   479  		readTestData(t, r, 0, testWriterStart.Add(time.Duration(i)*time.Hour), allEntries[i])
   480  	}
   481  }
   482  
   483  func TestReusingWriterAfterWriteError(t *testing.T) {
   484  	dir := createTempDir(t)
   485  	filePathPrefix := filepath.Join(dir, "")
   486  	defer os.RemoveAll(dir)
   487  
   488  	entries := []testEntry{
   489  		{"foo", nil, []byte{1, 2, 3}},
   490  		{"bar", nil, []byte{4, 5, 6}},
   491  	}
   492  	w := newTestWriter(t, filePathPrefix)
   493  	shard := uint32(0)
   494  	writerOpts := DataWriterOpenOptions{
   495  		Identifier: FileSetFileIdentifier{
   496  			Namespace:  testNs1ID,
   497  			Shard:      shard,
   498  			BlockStart: testWriterStart,
   499  		},
   500  	}
   501  	metadata := persist.NewMetadataFromIDAndTags(entries[0].ID(),
   502  		entries[0].Tags(),
   503  		persist.MetadataOptions{})
   504  	require.NoError(t, w.Open(writerOpts))
   505  
   506  	require.NoError(t, w.Write(metadata,
   507  		bytesRefd(entries[0].data),
   508  		digest.Checksum(entries[0].data)))
   509  
   510  	// Intentionally force a writer error.
   511  	w.(*writer).err = errors.New("foo")
   512  	metadata = persist.NewMetadataFromIDAndTags(entries[1].ID(),
   513  		entries[1].Tags(),
   514  		persist.MetadataOptions{})
   515  	require.Equal(t, "foo", w.Write(metadata,
   516  		bytesRefd(entries[1].data),
   517  		digest.Checksum(entries[1].data)).Error())
   518  	w.Close()
   519  
   520  	r := newTestReader(t, filePathPrefix)
   521  	rOpenOpts := DataReaderOpenOptions{
   522  		Identifier: FileSetFileIdentifier{
   523  			Namespace:  testNs1ID,
   524  			Shard:      shard,
   525  			BlockStart: testWriterStart,
   526  		},
   527  	}
   528  	require.Equal(t, ErrCheckpointFileNotFound, r.Open(rOpenOpts))
   529  
   530  	// Now reuse the writer and validate the data are written as expected.
   531  	writeTestData(t, w, shard, testWriterStart, entries, persist.FileSetFlushType)
   532  	readTestData(t, r, shard, testWriterStart, entries)
   533  }
   534  
   535  func TestWriterOnlyWritesNonNilBytes(t *testing.T) {
   536  	dir := createTempDir(t)
   537  	filePathPrefix := filepath.Join(dir, "")
   538  	defer os.RemoveAll(dir)
   539  
   540  	w := newTestWriter(t, filePathPrefix)
   541  	writerOpts := DataWriterOpenOptions{
   542  		BlockSize: testBlockSize,
   543  		Identifier: FileSetFileIdentifier{
   544  			Namespace:  testNs1ID,
   545  			Shard:      0,
   546  			BlockStart: testWriterStart,
   547  		},
   548  	}
   549  	metadata := persist.NewMetadataFromIDAndTags(
   550  		ident.StringID("foo"),
   551  		ident.Tags{},
   552  		persist.MetadataOptions{})
   553  	require.NoError(t, w.Open(writerOpts))
   554  
   555  	err := w.WriteAll(metadata,
   556  		[]checked.Bytes{
   557  			checkedBytes([]byte{1, 2, 3}),
   558  			nil,
   559  			checkedBytes([]byte{4, 5, 6}),
   560  		},
   561  		digest.Checksum([]byte{1, 2, 3, 4, 5, 6}))
   562  	require.NoError(t, err)
   563  
   564  	assert.NoError(t, w.Close())
   565  
   566  	r := newTestReader(t, filePathPrefix)
   567  	readTestData(t, r, 0, testWriterStart, []testEntry{
   568  		{"foo", nil, []byte{1, 2, 3, 4, 5, 6}},
   569  	})
   570  }
   571  
   572  func readData(
   573  	t *testing.T,
   574  	reader DataFileSetReader,
   575  ) (id ident.ID, tags ident.TagIterator, data checked.Bytes, checksum uint32, err error) {
   576  	if reader.StreamingEnabled() {
   577  		entry, err := reader.StreamingRead()
   578  		if err != nil {
   579  			return nil, nil, nil, 0, err
   580  		}
   581  		tags := decodeTags(t, entry.EncodedTags)
   582  		return entry.ID, tags, checked.NewBytes(entry.Data, nil), entry.DataChecksum, err
   583  	}
   584  
   585  	return reader.Read()
   586  }
   587  
   588  func readMetadata(
   589  	t *testing.T,
   590  	reader DataFileSetReader,
   591  ) (id ident.ID, tags ident.TagIterator, length int, checksum uint32, err error) {
   592  	if reader.StreamingEnabled() {
   593  		entry, err := reader.StreamingReadMetadata()
   594  		tags := decodeTags(t, entry.EncodedTags)
   595  		return entry.ID, tags, entry.Length, entry.DataChecksum, err
   596  	}
   597  
   598  	return reader.ReadMetadata()
   599  }
   600  
   601  func decodeTags(t *testing.T, encodedTags ts.EncodedTags) ident.TagIterator {
   602  	tags := ident.EmptyTagIterator
   603  	if len(encodedTags) > 0 {
   604  		tagsDecoder := testTagDecoderPool.Get()
   605  		tagsDecoder.Reset(checkedBytes(encodedTags))
   606  		require.NoError(t, tagsDecoder.Err())
   607  		tags = tagsDecoder
   608  	}
   609  
   610  	return tags
   611  }
   612  
   613  func checkedBytes(b []byte) checked.Bytes {
   614  	r := checked.NewBytes(b, nil)
   615  	r.IncRef()
   616  	return r
   617  }