minio/cmd/xl-storage-format-v2-legacy.go
Klaus Post faf013ec84
Improve performance on multiple versions (#13573)
Existing:

```go
type xlMetaV2 struct {
    Versions []xlMetaV2Version `json:"Versions" msg:"Versions"`
}
```

Serialized as regular MessagePack.

```go
//msgp:tuple xlMetaV2VersionHeader
type xlMetaV2VersionHeader struct {
	VersionID [16]byte
	ModTime   int64
	Type      VersionType
	Flags     xlFlags
}
```

Serialize as streaming MessagePack, format:

```
int(headerVersion)
int(xlmetaVersion)
int(nVersions)
for each version {
    binary blob, xlMetaV2VersionHeader, serialized
    binary blob, xlMetaV2Version, serialized.
}
```

xlMetaV2VersionHeader is <= 30 bytes serialized. Deserialized struct 
can easily be reused and does not contain pointers, so efficient as a 
slice (single allocation)

This allows quickly parsing everything as slices of bytes (no copy).

Versions are always *saved* sorted by modTime, newest *first*. 
No more need to sort on load.

* Allows checking if a version exists.
* Allows reading single version without unmarshal all.
* Allows reading latest version of type without unmarshal all.
* Allows reading latest version without unmarshal of all.
* Allows checking if the latest is deleteMarker by reading first entry.
* Allows adding/updating/deleting a version with only header deserialization.
* Reduces allocations on conversion to FileInfo(s).
2021-11-18 12:15:22 -08:00

90 lines
2.3 KiB
Go

// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package cmd
import (
"fmt"
"github.com/tinylib/msgp/msgp"
)
// unmarshalV unmarshals with a specific header version.
func (x *xlMetaV2VersionHeader) unmarshalV(v uint8, bts []byte) (o []byte, err error) {
switch v {
case 1:
return x.unmarshalV1(bts)
case xlHeaderVersion:
return x.UnmarshalMsg(bts)
}
return bts, fmt.Errorf("unknown xlHeaderVersion: %d", v)
}
// unmarshalV1 decodes version 1, never released.
func (x *xlMetaV2VersionHeader) unmarshalV1(bts []byte) (o []byte, err error) {
var zb0001 uint32
zb0001, bts, err = msgp.ReadArrayHeaderBytes(bts)
if err != nil {
err = msgp.WrapError(err)
return
}
if zb0001 != 4 {
err = msgp.ArrayError{Wanted: 4, Got: zb0001}
return
}
bts, err = msgp.ReadExactBytes(bts, (x.VersionID)[:])
if err != nil {
err = msgp.WrapError(err, "VersionID")
return
}
x.ModTime, bts, err = msgp.ReadInt64Bytes(bts)
if err != nil {
err = msgp.WrapError(err, "ModTime")
return
}
{
var zb0002 uint8
zb0002, bts, err = msgp.ReadUint8Bytes(bts)
if err != nil {
err = msgp.WrapError(err, "Type")
return
}
x.Type = VersionType(zb0002)
}
{
var zb0003 uint8
zb0003, bts, err = msgp.ReadUint8Bytes(bts)
if err != nil {
err = msgp.WrapError(err, "Flags")
return
}
x.Flags = xlFlags(zb0003)
}
o = bts
return
}
// unmarshalV unmarshals with a specific metadata version.
func (j *xlMetaV2Version) unmarshalV(v uint8, bts []byte) (o []byte, err error) {
switch v {
// We accept un-set as latest version.
case 0, xlMetaVersion:
return j.UnmarshalMsg(bts)
}
return bts, fmt.Errorf("unknown xlMetaVersion: %d", v)
}