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level_iter_test.go
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level_iter_test.go
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// Copyright 2018 The LevelDB-Go and Pebble and Bitalostored Authors. All rights reserved. Use
// of this source code is governed by a BSD-style license that can be found in
// the LICENSE file.
package bitalostable
import (
"bytes"
"fmt"
"strings"
"testing"
"time"
"github.com/stretchr/testify/require"
"github.com/zuoyebang/bitalostable/bloom"
"github.com/zuoyebang/bitalostable/internal/base"
"github.com/zuoyebang/bitalostable/internal/datadriven"
"github.com/zuoyebang/bitalostable/internal/keyspan"
"github.com/zuoyebang/bitalostable/internal/manifest"
"github.com/zuoyebang/bitalostable/internal/rangedel"
"github.com/zuoyebang/bitalostable/sstable"
"github.com/zuoyebang/bitalostable/vfs"
"golang.org/x/exp/rand"
)
const (
level = 1
)
func TestLevelIter(t *testing.T) {
var iters []*fakeIter
var files manifest.LevelSlice
newIters := func(
file *manifest.FileMetadata, opts *IterOptions, _ internalIterOpts,
) (internalIterator, keyspan.FragmentIterator, error) {
f := *iters[file.FileNum]
f.lower = opts.GetLowerBound()
f.upper = opts.GetUpperBound()
return &f, nil, nil
}
datadriven.RunTest(t, "testdata/level_iter", func(d *datadriven.TestData) string {
switch d.Cmd {
case "define":
iters = nil
var metas []*fileMetadata
for _, line := range strings.Split(d.Input, "\n") {
f := &fakeIter{}
for _, key := range strings.Fields(line) {
j := strings.Index(key, ":")
f.keys = append(f.keys, base.ParseInternalKey(key[:j]))
f.vals = append(f.vals, []byte(key[j+1:]))
}
iters = append(iters, f)
meta := (&fileMetadata{
FileNum: FileNum(len(metas)),
}).ExtendPointKeyBounds(
DefaultComparer.Compare,
f.keys[0],
f.keys[len(f.keys)-1],
)
metas = append(metas, meta)
}
files = manifest.NewLevelSliceKeySorted(base.DefaultComparer.Compare, metas)
return ""
case "iter":
var opts IterOptions
for _, arg := range d.CmdArgs {
if len(arg.Vals) != 1 {
return fmt.Sprintf("%s: %s=<value>", d.Cmd, arg.Key)
}
switch arg.Key {
case "lower":
opts.LowerBound = []byte(arg.Vals[0])
case "upper":
opts.UpperBound = []byte(arg.Vals[0])
default:
return fmt.Sprintf("%s: unknown arg: %s", d.Cmd, arg.Key)
}
}
iter := newLevelIter(opts, DefaultComparer.Compare,
func(a []byte) int { return len(a) }, newIters, files.Iter(), manifest.Level(level),
nil)
defer iter.Close()
// Fake up the range deletion initialization.
iter.initRangeDel(new(keyspan.FragmentIterator))
iter.disableInvariants = true
return runInternalIterCmd(d, iter, iterCmdVerboseKey)
case "load":
// The "load" command allows testing the iterator options passed to load
// sstables.
//
// load <key> [lower=<key>] [upper=<key>]
var opts IterOptions
var key string
for _, arg := range d.CmdArgs {
if len(arg.Vals) == 0 {
key = arg.Key
continue
}
if len(arg.Vals) != 1 {
return fmt.Sprintf("%s: %s=<value>", d.Cmd, arg.Key)
}
switch arg.Key {
case "lower":
opts.LowerBound = []byte(arg.Vals[0])
case "upper":
opts.UpperBound = []byte(arg.Vals[0])
default:
return fmt.Sprintf("%s: unknown arg: %s", d.Cmd, arg.Key)
}
}
var tableOpts *IterOptions
newIters2 := func(
file *manifest.FileMetadata, opts *IterOptions, internalOpts internalIterOpts,
) (internalIterator, keyspan.FragmentIterator, error) {
tableOpts = opts
return newIters(file, opts, internalOpts)
}
iter := newLevelIter(opts, DefaultComparer.Compare,
func(a []byte) int { return len(a) }, newIters2, files.Iter(),
manifest.Level(level), nil)
iter.SeekGE([]byte(key), base.SeekGEFlagsNone)
lower, upper := tableOpts.GetLowerBound(), tableOpts.GetUpperBound()
return fmt.Sprintf("[%s,%s]\n", lower, upper)
default:
return fmt.Sprintf("unknown command: %s", d.Cmd)
}
})
}
type levelIterTest struct {
cmp base.Comparer
mem vfs.FS
readers []*sstable.Reader
metas []*fileMetadata
itersCreated int
}
func newLevelIterTest() *levelIterTest {
lt := &levelIterTest{
cmp: *DefaultComparer,
mem: vfs.NewMem(),
}
lt.cmp.Split = func(a []byte) int { return len(a) }
return lt
}
func (lt *levelIterTest) newIters(
file *manifest.FileMetadata, opts *IterOptions, iio internalIterOpts,
) (internalIterator, keyspan.FragmentIterator, error) {
lt.itersCreated++
iter, err := lt.readers[file.FileNum].NewIterWithBlockPropertyFilters(opts.LowerBound, opts.UpperBound, nil, true, iio.stats)
if err != nil {
return nil, nil, err
}
rangeDelIter, err := lt.readers[file.FileNum].NewRawRangeDelIter()
if err != nil {
return nil, nil, err
}
return iter, rangeDelIter, nil
}
func (lt *levelIterTest) runClear(d *datadriven.TestData) string {
lt.mem = vfs.NewMem()
for _, r := range lt.readers {
r.Close()
}
lt.readers = nil
lt.metas = nil
lt.itersCreated = 0
return ""
}
func (lt *levelIterTest) runBuild(d *datadriven.TestData) string {
fileNum := FileNum(len(lt.readers))
name := fmt.Sprint(fileNum)
f0, err := lt.mem.Create(name)
if err != nil {
return err.Error()
}
tableFormat := sstable.TableFormatRocksDBv2
for _, arg := range d.CmdArgs {
if arg.Key == "format" {
switch arg.Vals[0] {
case "rocksdbv2":
tableFormat = sstable.TableFormatRocksDBv2
case "bitalostablev2":
tableFormat = sstable.TableFormatPebblev2
}
}
}
fp := bloom.FilterPolicy(10)
w := sstable.NewWriter(f0, sstable.WriterOptions{
Comparer: <.cmp,
FilterPolicy: fp,
TableFormat: tableFormat,
})
var tombstones []keyspan.Span
f := keyspan.Fragmenter{
Cmp: lt.cmp.Compare,
Format: lt.cmp.FormatKey,
Emit: func(fragmented keyspan.Span) {
tombstones = append(tombstones, fragmented)
},
}
for _, key := range strings.Split(d.Input, "\n") {
j := strings.Index(key, ":")
ikey := base.ParseInternalKey(key[:j])
value := []byte(key[j+1:])
switch ikey.Kind() {
case InternalKeyKindRangeDelete:
f.Add(rangedel.Decode(ikey, value, nil))
case InternalKeyKindRangeKeySet, InternalKeyKindRangeKeyUnset, InternalKeyKindRangeKeyDelete:
if err := w.AddRangeKey(ikey, value); err != nil {
return err.Error()
}
default:
if err := w.Add(ikey, value); err != nil {
return err.Error()
}
}
}
f.Finish()
for _, v := range tombstones {
if err := rangedel.Encode(&v, w.Add); err != nil {
return err.Error()
}
}
if err := w.Close(); err != nil {
return err.Error()
}
meta, err := w.Metadata()
if err != nil {
return err.Error()
}
f1, err := lt.mem.Open(name)
if err != nil {
return err.Error()
}
r, err := sstable.NewReader(f1, sstable.ReaderOptions{
Filters: map[string]FilterPolicy{
fp.Name(): fp,
},
})
if err != nil {
return err.Error()
}
lt.readers = append(lt.readers, r)
m := &fileMetadata{FileNum: fileNum}
if meta.HasPointKeys {
m.ExtendPointKeyBounds(lt.cmp.Compare, meta.SmallestPoint, meta.LargestPoint)
}
if meta.HasRangeDelKeys {
m.ExtendPointKeyBounds(lt.cmp.Compare, meta.SmallestRangeDel, meta.LargestRangeDel)
}
if meta.HasRangeKeys {
m.ExtendRangeKeyBounds(lt.cmp.Compare, meta.SmallestRangeKey, meta.LargestRangeKey)
}
lt.metas = append(lt.metas, m)
var buf bytes.Buffer
for _, f := range lt.metas {
fmt.Fprintf(&buf, "%d: %s-%s\n", f.FileNum, f.Smallest, f.Largest)
}
return buf.String()
}
func TestLevelIterBoundaries(t *testing.T) {
lt := newLevelIterTest()
defer lt.runClear(nil)
var iter *levelIter
datadriven.RunTest(t, "testdata/level_iter_boundaries", func(d *datadriven.TestData) string {
switch d.Cmd {
case "clear":
return lt.runClear(d)
case "build":
return lt.runBuild(d)
case "iter":
// The save and continue parameters allow us to save the iterator
// for later continued use.
save := false
cont := false
for _, arg := range d.CmdArgs {
switch arg.Key {
case "save":
save = true
case "continue":
cont = true
default:
return fmt.Sprintf("%s: unknown arg: %s", d.Cmd, arg.Key)
}
}
if !cont && iter != nil {
return "preceding iter was not closed"
}
if cont && iter == nil {
return "no existing iter"
}
if iter == nil {
slice := manifest.NewLevelSliceKeySorted(lt.cmp.Compare, lt.metas)
iter = newLevelIter(IterOptions{}, DefaultComparer.Compare,
func(a []byte) int { return len(a) }, lt.newIters, slice.Iter(),
manifest.Level(level), nil)
// Fake up the range deletion initialization.
iter.initRangeDel(new(keyspan.FragmentIterator))
}
if !save {
defer func() {
iter.Close()
iter = nil
}()
}
return runInternalIterCmd(d, iter, iterCmdVerboseKey)
case "file-pos":
// Returns the FileNum at which the iterator is positioned.
if iter == nil {
return "nil levelIter"
}
if iter.iterFile == nil {
return "nil iterFile"
}
return fmt.Sprintf("file %d", iter.iterFile.FileNum)
default:
return fmt.Sprintf("unknown command: %s", d.Cmd)
}
})
}
// levelIterTestIter allows a datadriven test to use runInternalIterCmd and
// perform parallel operations on both both a levelIter and rangeDelIter.
type levelIterTestIter struct {
*levelIter
rangeDelIter keyspan.FragmentIterator
}
func (i *levelIterTestIter) rangeDelSeek(
key []byte, ikey *InternalKey, val []byte, dir int,
) (*InternalKey, []byte) {
var tombstone keyspan.Span
if i.rangeDelIter != nil {
var t *keyspan.Span
if dir < 0 {
t = keyspan.SeekLE(i.levelIter.cmp, i.rangeDelIter, key)
} else {
t = keyspan.SeekGE(i.levelIter.cmp, i.rangeDelIter, key)
}
if t != nil {
tombstone = t.Visible(1000)
}
}
if ikey == nil {
return &InternalKey{
UserKey: []byte(fmt.Sprintf("./%s", tombstone)),
}, nil
}
return &InternalKey{
UserKey: []byte(fmt.Sprintf("%s/%s", ikey.UserKey, tombstone)),
Trailer: ikey.Trailer,
}, val
}
func (i *levelIterTestIter) String() string {
return "level-iter-test"
}
func (i *levelIterTestIter) SeekGE(key []byte, flags base.SeekGEFlags) (*InternalKey, []byte) {
ikey, val := i.levelIter.SeekGE(key, flags)
return i.rangeDelSeek(key, ikey, val, 1)
}
func (i *levelIterTestIter) SeekPrefixGE(
prefix, key []byte, flags base.SeekGEFlags,
) (*base.InternalKey, []byte) {
ikey, val := i.levelIter.SeekPrefixGE(prefix, key, flags)
return i.rangeDelSeek(key, ikey, val, 1)
}
func (i *levelIterTestIter) SeekLT(key []byte, flags base.SeekLTFlags) (*InternalKey, []byte) {
ikey, val := i.levelIter.SeekLT(key, flags)
return i.rangeDelSeek(key, ikey, val, -1)
}
func TestLevelIterSeek(t *testing.T) {
lt := newLevelIterTest()
defer lt.runClear(nil)
datadriven.RunTest(t, "testdata/level_iter_seek", func(d *datadriven.TestData) string {
switch d.Cmd {
case "clear":
return lt.runClear(d)
case "build":
return lt.runBuild(d)
case "iter":
var stats base.InternalIteratorStats
slice := manifest.NewLevelSliceKeySorted(lt.cmp.Compare, lt.metas)
iter := &levelIterTestIter{levelIter: &levelIter{}}
iter.init(IterOptions{}, DefaultComparer.Compare,
func(a []byte) int { return len(a) }, lt.newIters, slice.Iter(),
manifest.Level(level), internalIterOpts{stats: &stats})
defer iter.Close()
iter.initRangeDel(&iter.rangeDelIter)
return runInternalIterCmd(d, iter, iterCmdVerboseKey, iterCmdStats(&stats))
case "iters-created":
return fmt.Sprintf("%d", lt.itersCreated)
default:
return fmt.Sprintf("unknown command: %s", d.Cmd)
}
})
}
func buildLevelIterTables(
b *testing.B, blockSize, restartInterval, count int,
) ([]*sstable.Reader, manifest.LevelSlice, [][]byte, func()) {
mem := vfs.NewMem()
files := make([]vfs.File, count)
for i := range files {
f, err := mem.Create(fmt.Sprintf("bench%d", i))
if err != nil {
b.Fatal(err)
}
files[i] = f
}
writers := make([]*sstable.Writer, len(files))
for i := range files {
writers[i] = sstable.NewWriter(files[i], sstable.WriterOptions{
BlockRestartInterval: restartInterval,
BlockSize: blockSize,
Compression: NoCompression,
})
}
var keys [][]byte
var i int
const targetSize = 2 << 20
for _, w := range writers {
for ; w.EstimatedSize() < targetSize; i++ {
key := []byte(fmt.Sprintf("%08d", i))
keys = append(keys, key)
ikey := base.MakeInternalKey(key, 0, InternalKeyKindSet)
w.Add(ikey, nil)
}
if err := w.Close(); err != nil {
b.Fatal(err)
}
}
opts := sstable.ReaderOptions{Cache: NewCache(128 << 20)}
defer opts.Cache.Unref()
readers := make([]*sstable.Reader, len(files))
for i := range files {
f, err := mem.Open(fmt.Sprintf("bench%d", i))
if err != nil {
b.Fatal(err)
}
readers[i], err = sstable.NewReader(f, opts)
if err != nil {
b.Fatal(err)
}
}
cleanup := func() {
for _, r := range readers {
require.NoError(b, r.Close())
}
}
meta := make([]*fileMetadata, len(readers))
for i := range readers {
iter, err := readers[i].NewIter(nil /* lower */, nil /* upper */)
require.NoError(b, err)
smallest, _ := iter.First()
meta[i] = &fileMetadata{}
meta[i].FileNum = FileNum(i)
largest, _ := iter.Last()
meta[i].ExtendPointKeyBounds(opts.Comparer.Compare, (*smallest).Clone(), (*largest).Clone())
}
slice := manifest.NewLevelSliceKeySorted(base.DefaultComparer.Compare, meta)
return readers, slice, keys, cleanup
}
func BenchmarkLevelIterSeekGE(b *testing.B) {
const blockSize = 32 << 10
for _, restartInterval := range []int{16} {
b.Run(fmt.Sprintf("restart=%d", restartInterval),
func(b *testing.B) {
for _, count := range []int{5} {
b.Run(fmt.Sprintf("count=%d", count),
func(b *testing.B) {
readers, metas, keys, cleanup := buildLevelIterTables(b, blockSize, restartInterval, count)
defer cleanup()
newIters := func(
file *manifest.FileMetadata, _ *IterOptions, _ internalIterOpts,
) (internalIterator, keyspan.FragmentIterator, error) {
iter, err := readers[file.FileNum].NewIter(nil /* lower */, nil /* upper */)
return iter, nil, err
}
l := newLevelIter(IterOptions{}, DefaultComparer.Compare, nil, newIters, metas.Iter(), manifest.Level(level), nil)
rng := rand.New(rand.NewSource(uint64(time.Now().UnixNano())))
b.ResetTimer()
for i := 0; i < b.N; i++ {
l.SeekGE(keys[rng.Intn(len(keys))], base.SeekGEFlagsNone)
}
l.Close()
})
}
})
}
}
// A benchmark that simulates the behavior of a levelIter being used as part
// of a mergingIter where narrow bounds are repeatedly set and used to Seek
// and then iterate over the keys within the bounds. This resembles MVCC
// scanning by CockroachDB when doing a lookup/index join with a large number
// of left rows, that are batched and reuse the same iterator, and which can
// have good locality of access. This results in the successive bounds being
// in the same file.
func BenchmarkLevelIterSeqSeekGEWithBounds(b *testing.B) {
const blockSize = 32 << 10
for _, restartInterval := range []int{16} {
b.Run(fmt.Sprintf("restart=%d", restartInterval),
func(b *testing.B) {
for _, count := range []int{5} {
b.Run(fmt.Sprintf("count=%d", count),
func(b *testing.B) {
readers, metas, keys, cleanup :=
buildLevelIterTables(b, blockSize, restartInterval, count)
defer cleanup()
// This newIters is cheaper than in practice since it does not do
// tableCacheShard.findNode.
newIters := func(
file *manifest.FileMetadata, opts *IterOptions, _ internalIterOpts,
) (internalIterator, keyspan.FragmentIterator, error) {
iter, err := readers[file.FileNum].NewIter(
opts.LowerBound, opts.UpperBound)
return iter, nil, err
}
l := newLevelIter(IterOptions{}, DefaultComparer.Compare, nil, newIters, metas.Iter(), manifest.Level(level), nil)
// Fake up the range deletion initialization, to resemble the usage
// in a mergingIter.
l.initRangeDel(new(keyspan.FragmentIterator))
keyCount := len(keys)
b.ResetTimer()
for i := 0; i < b.N; i++ {
pos := i % (keyCount - 1)
l.SetBounds(keys[pos], keys[pos+1])
// SeekGE will return keys[pos].
k, _ := l.SeekGE(keys[pos], base.SeekGEFlagsNone)
// Next() will get called once and return nil.
for k != nil {
k, _ = l.Next()
}
}
l.Close()
})
}
})
}
}
// BenchmarkLevelIterSeqSeekPrefixGE simulates the behavior of a levelIter
// being used as part of a mergingIter where SeekPrefixGE is used to seek in a
// monotonically increasing manner. This resembles key-value lookups done by
// CockroachDB when evaluating Put operations.
func BenchmarkLevelIterSeqSeekPrefixGE(b *testing.B) {
const blockSize = 32 << 10
const restartInterval = 16
readers, metas, keys, cleanup :=
buildLevelIterTables(b, blockSize, restartInterval, 5)
defer cleanup()
// This newIters is cheaper than in practice since it does not do
// tableCacheShard.findNode.
newIters := func(
file *manifest.FileMetadata, opts *IterOptions, _ internalIterOpts,
) (internalIterator, keyspan.FragmentIterator, error) {
iter, err := readers[file.FileNum].NewIter(
opts.LowerBound, opts.UpperBound)
return iter, nil, err
}
for _, skip := range []int{1, 2, 4, 8, 16} {
for _, useNext := range []bool{false, true} {
b.Run(fmt.Sprintf("skip=%d/use-next=%t", skip, useNext),
func(b *testing.B) {
l := newLevelIter(IterOptions{}, DefaultComparer.Compare,
func(a []byte) int { return len(a) }, newIters, metas.Iter(),
manifest.Level(level), nil)
// Fake up the range deletion initialization, to resemble the usage
// in a mergingIter.
l.initRangeDel(new(keyspan.FragmentIterator))
keyCount := len(keys)
pos := 0
l.SeekPrefixGE(keys[pos], keys[pos], base.SeekGEFlagsNone)
b.ResetTimer()
for i := 0; i < b.N; i++ {
pos += skip
var flags base.SeekGEFlags
if useNext {
flags = flags.EnableTrySeekUsingNext()
}
if pos >= keyCount {
pos = 0
flags = flags.DisableTrySeekUsingNext()
}
// SeekPrefixGE will return keys[pos].
l.SeekPrefixGE(keys[pos], keys[pos], flags)
}
b.StopTimer()
l.Close()
})
}
}
}
func BenchmarkLevelIterNext(b *testing.B) {
const blockSize = 32 << 10
for _, restartInterval := range []int{16} {
b.Run(fmt.Sprintf("restart=%d", restartInterval),
func(b *testing.B) {
for _, count := range []int{5} {
b.Run(fmt.Sprintf("count=%d", count),
func(b *testing.B) {
readers, metas, _, cleanup := buildLevelIterTables(b, blockSize, restartInterval, count)
defer cleanup()
newIters := func(
file *manifest.FileMetadata, _ *IterOptions, _ internalIterOpts,
) (internalIterator, keyspan.FragmentIterator, error) {
iter, err := readers[file.FileNum].NewIter(nil /* lower */, nil /* upper */)
return iter, nil, err
}
l := newLevelIter(IterOptions{}, DefaultComparer.Compare, nil, newIters, metas.Iter(), manifest.Level(level), nil)
b.ResetTimer()
for i := 0; i < b.N; i++ {
key, _ := l.Next()
if key == nil {
key, _ = l.First()
}
_ = key
}
l.Close()
})
}
})
}
}
func BenchmarkLevelIterPrev(b *testing.B) {
const blockSize = 32 << 10
for _, restartInterval := range []int{16} {
b.Run(fmt.Sprintf("restart=%d", restartInterval),
func(b *testing.B) {
for _, count := range []int{5} {
b.Run(fmt.Sprintf("count=%d", count),
func(b *testing.B) {
readers, metas, _, cleanup := buildLevelIterTables(b, blockSize, restartInterval, count)
defer cleanup()
newIters := func(
file *manifest.FileMetadata, _ *IterOptions, _ internalIterOpts,
) (internalIterator, keyspan.FragmentIterator, error) {
iter, err := readers[file.FileNum].NewIter(nil /* lower */, nil /* upper */)
return iter, nil, err
}
l := newLevelIter(IterOptions{}, DefaultComparer.Compare, nil, newIters, metas.Iter(), manifest.Level(level), nil)
b.ResetTimer()
for i := 0; i < b.N; i++ {
key, _ := l.Prev()
if key == nil {
key, _ = l.Last()
}
_ = key
}
l.Close()
})
}
})
}
}