Files
seaweedfs/weed/util/log_buffer/read_ts_test.go
T
Chris LuandGitHub 6413b774df filer: cut metadata-subscription allocation churn (issue #10253) (#10260)
* log_buffer: read only ts_ns during metadata-read binary search

readTs ran a full proto.Unmarshal of each LogEntry just to compare
timestamps during ReadFromBuffer's binary search, allocating fresh
slices for the data and key byte fields on every probe. Under
metadata-subscription fan-out this decode churn dominated allocations
and drove heavy GC, inflating filer RSS well past the live heap.

Scan the wire format for ts_ns (field 1) instead and skip the data/key
payloads without copying them. readTs is now zero-alloc; the binary
search no longer touches the event payloads at all.

* log_buffer: alias event payloads instead of copying them on delivery

The subscribe read loops decoded each LogEntry with a full proto.Unmarshal,
allocating fresh slices for the data and key byte fields on every entry
(protobuf consumeBytesNoZero). When many metadata subscribers each re-read
the in-memory log window under a reconnect storm, that per-entry copy was a
large share of allocation churn -- and for entries a subscriber filters out
by prefix, the copied payload was never even looked at.

Decode with a wire scan that points data/key at sub-slices of the source
buffer instead of copying. The aliased slices are valid only for the
duration of the eachLogEntryFn callback; every current subscriber either
re-decodes the event into its own struct or hands it to a synchronous grpc
Send, so none retain them. Per delivered entry the loop decode drops from
176 B / 2 allocs to zero.
2026-07-08 00:05:20 -07:00

231 lines
6.9 KiB
Go

package log_buffer
import (
"bytes"
"math"
"math/rand"
"testing"
"google.golang.org/protobuf/proto"
"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
"github.com/seaweedfs/seaweedfs/weed/util"
)
// readTsNs must return exactly what a full proto.Unmarshal would put in TsNs,
// for every field combination, without decoding data/key.
func TestReadTsNsMatchesUnmarshal(t *testing.T) {
cases := []*filer_pb.LogEntry{
{}, // all defaults: ts_ns absent on the wire => 0
{TsNs: 1}, // minimal
{TsNs: 1783396413597780505}, // realistic nanosecond timestamp
{TsNs: math.MaxInt64}, // 9-byte varint
{TsNs: -1}, // negative int64 => 10-byte varint
{TsNs: math.MinInt64}, // extreme negative
{TsNs: 42, PartitionKeyHash: 7}, // ts followed by another varint field
{TsNs: 12345, Data: []byte("some-metadata-event-payload"), Key: []byte("/buckets/pvc-x/1.log")},
{TsNs: 99, Data: make([]byte, 64*1024), Key: []byte("k"), Offset: 555}, // large data, all fields
{Data: []byte("no-ts"), Key: []byte("k"), Offset: 9}, // ts_ns == 0 with other fields present
}
for i, e := range cases {
data, err := proto.Marshal(e)
if err != nil {
t.Fatalf("case %d marshal: %v", i, err)
}
got, err := readTsNs(data)
if err != nil {
t.Fatalf("case %d readTsNs: %v", i, err)
}
if got != e.TsNs {
t.Errorf("case %d: readTsNs=%d want %d", i, got, e.TsNs)
}
}
}
// Fuzz against proto.Unmarshal with randomized entries.
func TestReadTsNsFuzz(t *testing.T) {
r := rand.New(rand.NewSource(1))
for i := 0; i < 5000; i++ {
e := &filer_pb.LogEntry{
TsNs: r.Int63() - r.Int63(),
PartitionKeyHash: r.Int31(),
Offset: r.Int63(),
}
if r.Intn(2) == 0 {
e.Data = make([]byte, r.Intn(300))
r.Read(e.Data)
}
if r.Intn(2) == 0 {
e.Key = make([]byte, r.Intn(64))
r.Read(e.Key)
}
data, err := proto.Marshal(e)
if err != nil {
t.Fatalf("marshal: %v", err)
}
var want filer_pb.LogEntry
if err := proto.Unmarshal(data, &want); err != nil {
t.Fatalf("unmarshal: %v", err)
}
got, err := readTsNs(data)
if err != nil {
t.Fatalf("readTsNs iter %d: %v", i, err)
}
if got != want.TsNs {
t.Fatalf("iter %d: readTsNs=%d want %d", i, got, want.TsNs)
}
}
}
// readTsNs must not panic and must report an error on truncated/garbage input.
func TestReadTsNsCorrupted(t *testing.T) {
inputs := [][]byte{
{0x08}, // ts_ns tag with no value
{0x1a, 0xff, 0xff, 0xff}, // data field, length overruns buffer
{0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x7f}, // overlong tag
}
for i, in := range inputs {
if _, err := readTsNs(in); err == nil {
t.Errorf("input %d: expected error, got nil", i)
}
}
}
// unmarshalLogEntryAliased must produce the same fields as proto.Unmarshal.
func TestUnmarshalLogEntryAliasedMatchesUnmarshal(t *testing.T) {
r := rand.New(rand.NewSource(2))
for i := 0; i < 5000; i++ {
e := &filer_pb.LogEntry{
TsNs: r.Int63() - r.Int63(),
PartitionKeyHash: r.Int31() - r.Int31(),
Offset: r.Int63() - r.Int63(),
}
if r.Intn(2) == 0 {
e.Data = make([]byte, r.Intn(4096))
r.Read(e.Data)
}
if r.Intn(2) == 0 {
e.Key = make([]byte, r.Intn(128))
r.Read(e.Key)
}
data, err := proto.Marshal(e)
if err != nil {
t.Fatalf("marshal: %v", err)
}
var want, got filer_pb.LogEntry
if err := proto.Unmarshal(data, &want); err != nil {
t.Fatalf("unmarshal: %v", err)
}
if err := unmarshalLogEntryAliased(data, &got); err != nil {
t.Fatalf("aliased iter %d: %v", i, err)
}
if got.TsNs != want.TsNs || got.PartitionKeyHash != want.PartitionKeyHash ||
got.Offset != want.Offset || !bytes.Equal(got.Data, want.Data) || !bytes.Equal(got.Key, want.Key) {
t.Fatalf("iter %d mismatch:\n got=%+v\nwant=%+v", i, &got, &want)
}
}
}
// The decoded data/key must point into the source buffer, not a copy.
func TestUnmarshalLogEntryAliasedAliases(t *testing.T) {
data, err := proto.Marshal(&filer_pb.LogEntry{TsNs: 5, Data: []byte("payload"), Key: []byte("path")})
if err != nil {
t.Fatal(err)
}
var out filer_pb.LogEntry
if err := unmarshalLogEntryAliased(data, &out); err != nil {
t.Fatal(err)
}
if string(out.Data) != "payload" || string(out.Key) != "path" {
t.Fatalf("decoded data=%q key=%q", out.Data, out.Key)
}
for i := range data { // mutate source; an alias must observe it, a copy must not
data[i] ^= 0xFF
}
if string(out.Data) == "payload" || string(out.Key) == "path" {
t.Fatal("data/key were copied, expected an alias into the source buffer")
}
}
// sampleEntryData returns a marshaled LogEntry whose Data is a realistic
// marshaled metadata event, as delivered on the subscribe path.
func sampleEntryData(tb testing.TB) []byte {
event := &filer_pb.SubscribeMetadataResponse{
Directory: "/buckets/pvc-bf458866-0413-4cca-99c6-3b7386a80855",
EventNotification: &filer_pb.EventNotification{
NewEntry: &filer_pb.Entry{
Name: "object-000123",
Attributes: &filer_pb.FuseAttributes{FileSize: 4096, Mtime: 1783396413},
Chunks: []*filer_pb.FileChunk{
{FileId: "3,01637037d6", Size: 4096, Fid: &filer_pb.FileId{VolumeId: 3, FileKey: 23283, Cookie: 2015}},
},
},
},
}
payload, err := proto.Marshal(event)
if err != nil {
tb.Fatal(err)
}
data, err := proto.Marshal(&filer_pb.LogEntry{
TsNs: 1783396413597780505, PartitionKeyHash: 12345, Offset: 2013258,
Key: []byte("/buckets/pvc-bf458866/object-000123"), Data: payload,
})
if err != nil {
tb.Fatal(err)
}
return data
}
// Per-entry decode cost on the delivery path: the old full unmarshal copies the
// data/key byte fields; the aliased decode does not. The delta is what the fix
// saves for every entry a subscriber reads (and, for non-matching entries a
// subscriber filters out, the whole saving with nothing decoded downstream).
func BenchmarkLogEntryDecodeCopy(b *testing.B) {
data := sampleEntryData(b)
var out filer_pb.LogEntry
b.ReportAllocs()
b.ResetTimer()
for i := 0; i < b.N; i++ {
if err := proto.Unmarshal(data, &out); err != nil {
b.Fatal(err)
}
}
}
func BenchmarkLogEntryDecodeAlias(b *testing.B) {
data := sampleEntryData(b)
var out filer_pb.LogEntry
b.ReportAllocs()
b.ResetTimer()
for i := 0; i < b.N; i++ {
if err := unmarshalLogEntryAliased(data, &out); err != nil {
b.Fatal(err)
}
}
}
func BenchmarkReadTs(b *testing.B) {
e := &filer_pb.LogEntry{
TsNs: 1783396413597780505,
PartitionKeyHash: 12345,
Data: make([]byte, 4*1024), // typical metadata event payload
Key: []byte("/buckets/pvc-bf458866/1.log"),
Offset: 2013258,
}
data, err := proto.Marshal(e)
if err != nil {
b.Fatal(err)
}
buf := make([]byte, 4+len(data))
util.Uint32toBytes(buf, uint32(len(data)))
copy(buf[4:], data)
b.ReportAllocs()
b.ResetTimer()
for i := 0; i < b.N; i++ {
if _, _, err := readTs(buf, 0); err != nil {
b.Fatal(err)
}
}
}