{"record":{"id":"60d42a23045a1135","repo":"juicedata/juicefs","slug":"failed-to-marshal-segment-s-v","errorCode":null,"errorMessage":"failed to marshal segment %s: %v","messagePattern":"failed to marshal segment (.+?): (.+?)","errorType":"exception","errorClass":null,"httpStatus":null,"severity":"error","filePath":"pkg/meta/backup.go","lineNumber":126,"sourceCode":"\treturn &BakFormat{\n\t\tFooter: &BakFooter{\n\t\t\tMsg: &pb.Footer{\n\t\t\t\tMagic:   BakMagic,\n\t\t\t\tVersion: BakVersion,\n\t\t\t\tInfos:   make(map[string]*pb.Footer_SegInfo),\n\t\t\t},\n\t\t},\n\t}\n}\n\nfunc (f *BakFormat) writeSegment(w io.Writer, seg *BakSegment) error {\n\tif seg == nil {\n\t\treturn nil\n\t}\n\n\tn, err := seg.Marshal(w)\n\tif err != nil {\n\t\treturn fmt.Errorf(\"failed to marshal segment %s: %v\", seg, err)\n\t}\n\n\tname := seg.Name()\n\tinfo, ok := f.Footer.Msg.Infos[name]\n\tif !ok {\n\t\tinfo = &pb.Footer_SegInfo{Offset: []uint64{}, Num: 0}\n\t\tf.Footer.Msg.Infos[name] = info\n\t}\n\n\tinfo.Offset = append(info.Offset, f.Pos)\n\tinfo.Num += seg.num()\n\tf.Pos += uint64(n)\n\treturn nil\n}\n\nfunc (f *BakFormat) ReadSegment(r io.Reader) (*BakSegment, error) {\n\tseg := &BakSegment{}\n\tif err := seg.Unmarshal(r); err != nil {","sourceCodeStart":108,"sourceCodeEnd":144,"githubUrl":"https://github.com/juicedata/juicefs/blob/c9a67b23e8e08ec23ec331aa6f1675e2319e921c/pkg/meta/backup.go#L108-L144","documentation":"writeSegment serializes a backup segment into the output stream via protobuf Marshal. If marshalling fails (nil descriptor, required field unset, oversized message), the segment cannot be written and DumpMetaV2 aborts with this wrapped error.","triggerScenarios":"Calling DumpMetaV2 on a metadata engine whose record fails proto.Marshal — e.g. a segment message with fields that exceed protobuf limits or a corrupt in-memory record read from Redis/SQL/KV.","commonSituations":"Dumping metadata from an engine with records written by incompatible client versions containing unexpected data; extremely large single records (huge xattr/ACL) hitting protobuf size limits.","solutions":["Retry the dump after upgrading all clients to a compatible version","Identify the offending segment (it is printed in the error) and inspect the corresponding metadata record","Report/repair the corrupt record in the metadata engine, then re-run the dump"],"exampleFix":null,"handlingStrategy":"retry","validationCode":null,"typeGuard":null,"tryCatchPattern":"err := dumpMetaV2(ctx, w)\nif err != nil {\n    if strings.Contains(err.Error(), \"failed to marshal segment\") {\n        log.Printf(\"corrupt metadata record during dump: %v; check engine health\", err)\n    }\n    return err\n}","preventionTips":["Keep all clients on compatible versions","Monitor metadata engine health before large dumps","Dump to local disk, then upload"],"tags":["backup","protobuf","dump","serialization"],"backgroundTag":"protobuf-marshal-failed","analyzedSha":"c9a67b23e8e08ec23ec331aa6f1675e2319e921c","analyzedAt":"2026-09-06T17:55:48.476Z","contentChangedAt":"2026-09-06T17:55:48.476Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}