ceremonyclient/pebble/snapshot_test.go

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2024-01-03 07:31:42 +00:00
// Copyright 2012 The LevelDB-Go and Pebble 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 pebble
import (
"bytes"
"fmt"
"math/rand"
"reflect"
"runtime"
"strings"
"sync"
"testing"
"time"
"github.com/cockroachdb/datadriven"
"github.com/cockroachdb/errors"
"github.com/cockroachdb/pebble/vfs"
"github.com/stretchr/testify/require"
)
func TestSnapshotListToSlice(t *testing.T) {
testCases := []struct {
vals []uint64
}{
{nil},
{[]uint64{1}},
{[]uint64{1, 2, 3}},
{[]uint64{3, 2, 1}},
}
for _, c := range testCases {
t.Run("", func(t *testing.T) {
var l snapshotList
l.init()
for _, v := range c.vals {
l.pushBack(&Snapshot{seqNum: v})
}
slice := l.toSlice()
if !reflect.DeepEqual(c.vals, slice) {
t.Fatalf("expected %d, but got %d", c.vals, slice)
}
})
}
}
func testSnapshotImpl(t *testing.T, newSnapshot func(d *DB) Reader) {
var d *DB
var snapshots map[string]Reader
close := func() {
for _, s := range snapshots {
require.NoError(t, s.Close())
}
snapshots = nil
if d != nil {
require.NoError(t, d.Close())
d = nil
}
}
defer close()
randVersion := func() FormatMajorVersion {
minVersion := formatUnusedPrePebblev1MarkedCompacted
return FormatMajorVersion(int(minVersion) + rand.Intn(
int(internalFormatNewest)-int(minVersion)+1))
}
datadriven.RunTest(t, "testdata/snapshot", func(t *testing.T, td *datadriven.TestData) string {
switch td.Cmd {
case "define":
close()
var err error
options := &Options{
FS: vfs.NewMem(),
FormatMajorVersion: randVersion(),
}
if td.HasArg("block-size") {
var blockSize int
td.ScanArgs(t, "block-size", &blockSize)
options.Levels = make([]LevelOptions, 1)
options.Levels[0].BlockSize = blockSize
options.Levels[0].IndexBlockSize = blockSize
}
d, err = Open("", options)
if err != nil {
return err.Error()
}
snapshots = make(map[string]Reader)
for _, line := range strings.Split(td.Input, "\n") {
parts := strings.Fields(line)
if len(parts) == 0 {
continue
}
var err error
switch parts[0] {
case "set":
if len(parts) != 3 {
return fmt.Sprintf("%s expects 2 arguments", parts[0])
}
err = d.Set([]byte(parts[1]), []byte(parts[2]), nil)
case "del":
if len(parts) != 2 {
return fmt.Sprintf("%s expects 1 argument", parts[0])
}
err = d.Delete([]byte(parts[1]), nil)
case "merge":
if len(parts) != 3 {
return fmt.Sprintf("%s expects 2 arguments", parts[0])
}
err = d.Merge([]byte(parts[1]), []byte(parts[2]), nil)
case "snapshot":
if len(parts) != 2 {
return fmt.Sprintf("%s expects 1 argument", parts[0])
}
snapshots[parts[1]] = newSnapshot(d)
case "compact":
if len(parts) != 2 {
return fmt.Sprintf("%s expects 1 argument", parts[0])
}
keys := strings.Split(parts[1], "-")
if len(keys) != 2 {
return fmt.Sprintf("malformed key range: %s", parts[1])
}
err = d.Compact([]byte(keys[0]), []byte(keys[1]), false)
default:
return fmt.Sprintf("unknown op: %s", parts[0])
}
if err != nil {
return err.Error()
}
}
return ""
case "db-state":
d.mu.Lock()
s := d.mu.versions.currentVersion().String()
d.mu.Unlock()
return s
case "iter":
var iter *Iterator
if len(td.CmdArgs) == 1 {
if td.CmdArgs[0].Key != "snapshot" {
return fmt.Sprintf("unknown argument: %s", td.CmdArgs[0])
}
if len(td.CmdArgs[0].Vals) != 1 {
return fmt.Sprintf("%s expects 1 value: %s", td.CmdArgs[0].Key, td.CmdArgs[0])
}
name := td.CmdArgs[0].Vals[0]
snapshot := snapshots[name]
if snapshot == nil {
return fmt.Sprintf("unable to find snapshot \"%s\"", name)
}
iter, _ = snapshot.NewIter(nil)
} else {
iter, _ = d.NewIter(nil)
}
defer iter.Close()
var b bytes.Buffer
for _, line := range strings.Split(td.Input, "\n") {
parts := strings.Fields(line)
if len(parts) == 0 {
continue
}
switch parts[0] {
case "first":
iter.First()
case "last":
iter.Last()
case "seek-ge":
if len(parts) != 2 {
return "seek-ge <key>\n"
}
iter.SeekGE([]byte(strings.TrimSpace(parts[1])))
case "seek-lt":
if len(parts) != 2 {
return "seek-lt <key>\n"
}
iter.SeekLT([]byte(strings.TrimSpace(parts[1])))
case "next":
iter.Next()
case "prev":
iter.Prev()
default:
return fmt.Sprintf("unknown op: %s", parts[0])
}
if iter.Valid() {
fmt.Fprintf(&b, "%s:%s\n", iter.Key(), iter.Value())
} else if err := iter.Error(); err != nil {
fmt.Fprintf(&b, "err=%v\n", err)
} else {
fmt.Fprintf(&b, ".\n")
}
}
return b.String()
default:
return fmt.Sprintf("unknown command: %s", td.Cmd)
}
})
}
func TestSnapshot(t *testing.T) {
testSnapshotImpl(t, func(d *DB) Reader {
return d.NewSnapshot()
})
}
func TestEventuallyFileOnlySnapshot(t *testing.T) {
testSnapshotImpl(t, func(d *DB) Reader {
// NB: all keys in testdata/snapshot fall within the ASCII keyrange a-z.
return d.NewEventuallyFileOnlySnapshot([]KeyRange{{Start: []byte("a"), End: []byte("z")}})
})
}
func TestSnapshotClosed(t *testing.T) {
d, err := Open("", &Options{
FS: vfs.NewMem(),
})
require.NoError(t, err)
catch := func(f func()) (err error) {
defer func() {
if r := recover(); r != nil {
err = r.(error)
}
}()
f()
return nil
}
snap := d.NewSnapshot()
require.NoError(t, snap.Close())
require.True(t, errors.Is(catch(func() { _ = snap.Close() }), ErrClosed))
require.True(t, errors.Is(catch(func() { _, _, _ = snap.Get(nil) }), ErrClosed))
require.True(t, errors.Is(catch(func() { snap.NewIter(nil) }), ErrClosed))
require.NoError(t, d.Close())
}
func TestSnapshotRangeDeletionStress(t *testing.T) {
const runs = 200
const middleKey = runs * runs
d, err := Open("", &Options{
FS: vfs.NewMem(),
})
require.NoError(t, err)
mkkey := func(k int) []byte {
return []byte(fmt.Sprintf("%08d", k))
}
v := []byte("hello world")
snapshots := make([]*Snapshot, 0, runs)
for r := 0; r < runs; r++ {
// We use a keyspace that is 2*runs*runs wide. In other words there are
// 2*runs sections of the keyspace, each with runs elements. On every
// run, we write to the r-th element of each section of the keyspace.
for i := 0; i < 2*runs; i++ {
err := d.Set(mkkey(runs*i+r), v, nil)
require.NoError(t, err)
}
// Now we delete some of the keyspace through a DeleteRange. We delete from
// the middle of the keyspace outwards. The keyspace is made of 2*runs
// sections, and we delete an additional two of these sections per run.
err := d.DeleteRange(mkkey(middleKey-runs*r), mkkey(middleKey+runs*r), nil)
require.NoError(t, err)
snapshots = append(snapshots, d.NewSnapshot())
}
// Check that all the snapshots contain the expected number of keys.
// Iterating over so many keys is slow, so do it in parallel.
var wg sync.WaitGroup
sem := make(chan struct{}, runtime.GOMAXPROCS(0))
for r := range snapshots {
wg.Add(1)
sem <- struct{}{}
go func(r int) {
defer func() {
<-sem
wg.Done()
}()
// Count the keys at this snapshot.
iter, _ := snapshots[r].NewIter(nil)
var keysFound int
for iter.First(); iter.Valid(); iter.Next() {
keysFound++
}
err := firstError(iter.Error(), iter.Close())
if err != nil {
t.Error(err)
return
}
// At the time that this snapshot was taken, (r+1)*2*runs unique keys
// were Set (one in each of the 2*runs sections per run). But this
// run also deleted the 2*r middlemost sections. When this snapshot
// was taken, a Set to each of those sections had been made (r+1)
// times, so 2*r*(r+1) previously-set keys are now deleted.
keysExpected := (r+1)*2*runs - 2*r*(r+1)
if keysFound != keysExpected {
t.Errorf("%d: found %d keys, want %d", r, keysFound, keysExpected)
}
if err := snapshots[r].Close(); err != nil {
t.Error(err)
}
}(r)
}
wg.Wait()
require.NoError(t, d.Close())
}
// TestNewSnapshotRace tests atomicity of NewSnapshot.
//
// It tests for a regression of a previous race condition in which NewSnapshot
// would retrieve the visible sequence number for a new snapshot before
// locking the database mutex to add the snapshot. A write and flush that
// that occurred between the reading of the sequence number and appending the
// snapshot could drop keys required by the snapshot.
func TestNewSnapshotRace(t *testing.T) {
const runs = 10
d, err := Open("", &Options{FS: vfs.NewMem()})
require.NoError(t, err)
v := []byte(`foo`)
ch := make(chan string)
var wg sync.WaitGroup
wg.Add(1)
go func() {
defer wg.Done()
for k := range ch {
if err := d.Set([]byte(k), v, nil); err != nil {
t.Error(err)
return
}
if err := d.Flush(); err != nil {
t.Error(err)
return
}
}
}()
for i := 0; i < runs; i++ {
// This main test goroutine sets `k` before creating a new snapshot.
// The key `k` should always be present within the snapshot.
k := fmt.Sprintf("key%06d", i)
require.NoError(t, d.Set([]byte(k), v, nil))
// Lock d.mu in another goroutine so that our call to NewSnapshot
// will need to contend for d.mu.
wg.Add(1)
locked := make(chan struct{})
go func() {
defer wg.Done()
d.mu.Lock()
close(locked)
time.Sleep(20 * time.Millisecond)
d.mu.Unlock()
}()
<-locked
// Tell the other goroutine to overwrite `k` with a later sequence
// number. It's indeterminate which key we'll read, but we should
// always read one of them.
ch <- k
s := d.NewSnapshot()
_, c, err := s.Get([]byte(k))
require.NoError(t, err)
require.NoError(t, c.Close())
require.NoError(t, s.Close())
}
close(ch)
wg.Wait()
require.NoError(t, d.Close())
}