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replication: Support GTID tag in PreviousGTIDsEvent #952

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replication: Support GTID tag in PreviousGTIDsEvent #952

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b2d723a
replication: Support GTID tag in PreviousGTIDsEvent
dveeden Nov 21, 2024
03ef43c
Add test
dveeden Nov 21, 2024
4a647d0
Add more tests
dveeden Nov 21, 2024
19d01d1
Merge branch 'master' into gtid_tag
dveeden Nov 26, 2024
ea2270a
Update replication/event.go
dveeden Nov 27, 2024
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57 changes: 53 additions & 4 deletions replication/event.go
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Original file line number Diff line number Diff line change
Expand Up @@ -229,15 +229,59 @@ type PreviousGTIDsEvent struct {
GTIDSets string
}

type GtidFormat int

const (
GtidFormatClassic = iota
GtidFormatTagged
)

func decodeSid(data []byte) (format GtidFormat, sidnr uint64) {
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can you put the referenced MySQL source code or document in comment, so other reviewers can double check the implementation?

if data[7] == 1 {
format = GtidFormatTagged
}

if format == GtidFormatTagged {
sid_mask := []byte{0, 255, 255, 255, 255, 255, 255, 0}

// Apply the mask
for i, _ := range data[:8] {
data[i] &= sid_mask[i]
}
data = append(data, 0)

// sidnr
sidnr = binary.LittleEndian.Uint64(data[1:])
return
}
sidnr = binary.LittleEndian.Uint64(data)
return
}

func (e *PreviousGTIDsEvent) Decode(data []byte) error {
pos := 0
uuidCount := binary.LittleEndian.Uint16(data[pos : pos+8])

gtidinfo := make([]byte, 8)
copy(gtidinfo, data[:8])
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I see that the new copy is caused by decodeSid will modify data in-place. How about let decodeSid copy the needed data? So there's no risk that in future we need to change the code and caller forget to copy it.

format, uuidCount := decodeSid(gtidinfo)
pos += 8

previousGTIDSets := make([]string, uuidCount)
for i := range previousGTIDSets {
currentSetnr := 0
for _ = range previousGTIDSets {
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uuid := e.decodeUuid(data[pos : pos+16])
pos += 16
isTag := false
var tag string
if format == GtidFormatTagged {
tagLength := int(data[pos]) / 2
pos += 1
if tagLength > 0 {
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can the tag have zero length? please add comments

isTag = true
tag = string(data[pos : pos+tagLength])
pos += tagLength
}
}
sliceCount := binary.LittleEndian.Uint16(data[pos : pos+8])
pos += 8
intervals := make([]string, sliceCount)
Expand All @@ -254,9 +298,14 @@ func (e *PreviousGTIDsEvent) Decode(data []byte) error {
}
intervals[i] = interval
}
previousGTIDSets[i] = fmt.Sprintf("%s:%s", uuid, strings.Join(intervals, ":"))
if isTag {
previousGTIDSets[currentSetnr-1] += fmt.Sprintf(":%s:%s", tag, strings.Join(intervals, ":"))
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Because string is immutable, string += will create a new string object each time. If there are too many tags the performance will drop. Maybe store every "tag+intervals" and join them once at all

} else {
previousGTIDSets[currentSetnr] = fmt.Sprintf("%s:%s", uuid, strings.Join(intervals, ":"))
currentSetnr += 1
}
}
e.GTIDSets = strings.Join(previousGTIDSets, ",")
e.GTIDSets = strings.Join(previousGTIDSets[:currentSetnr], ",")
return nil
}

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50 changes: 50 additions & 0 deletions replication/event_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -140,3 +140,53 @@ func TestIntVarEvent(t *testing.T) {
require.Equal(t, INSERT_ID, ev.Type)
require.Equal(t, uint64(23), ev.Value)
}

func TestDecodeSid(t *testing.T) {
testcases := []struct {
input []byte
gtidFormat GtidFormat
uuidCount uint64
}{
{[]byte{1, 2, 0, 0, 0, 0, 0, 1}, GtidFormatTagged, 2},
{[]byte{1, 1, 0, 0, 0, 0, 0, 1}, GtidFormatTagged, 1},
{[]byte{1, 0, 0, 0, 0, 0, 0, 1}, GtidFormatTagged, 0},
{[]byte{1, 0, 0, 0, 0, 0, 0, 0}, GtidFormatClassic, 1},
}

for _, tc := range testcases {
format, uuidCount := decodeSid(tc.input)
assert.Equal(t, tc.gtidFormat, format)
assert.Equal(t, tc.uuidCount, uuidCount)
}
}

func TestPreviousGTIDEvent(t *testing.T) {
testcases := []struct {
input []byte
GTIDSets string
}{
{
[]byte{0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1},
"",
},
{
[]byte{0x1, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x89, 0x6e, 0x78, 0x82, 0x18, 0xfe, 0x11, 0xef, 0xab, 0x88, 0x22, 0x22, 0x2d, 0x34, 0xd4, 0x11, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x4, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
"896e7882-18fe-11ef-ab88-22222d34d411:1-3",
},
{
[]byte{0x1, 0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x89, 0x6e, 0x78, 0x82, 0x18, 0xfe, 0x11, 0xef, 0xab, 0x88, 0x22, 0x22, 0x2d, 0x34, 0xd4, 0x11, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x5, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x89, 0x6e, 0x78, 0x82, 0x18, 0xfe, 0x11, 0xef, 0xab, 0x88, 0x22, 0x22, 0x2d, 0x34, 0xd4, 0x11, 0x8, 0x61, 0x61, 0x61, 0x61, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
"896e7882-18fe-11ef-ab88-22222d34d411:1-4:aaaa:1",
},
{
[]byte{0x1, 0x7, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x89, 0x6e, 0x78, 0x82, 0x18, 0xfe, 0x11, 0xef, 0xab, 0x88, 0x22, 0x22, 0x2d, 0x34, 0xd4, 0x11, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x5, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x89, 0x6e, 0x78, 0x82, 0x18, 0xfe, 0x11, 0xef, 0xab, 0x88, 0x22, 0x22, 0x2d, 0x34, 0xd4, 0x11, 0x8, 0x61, 0x61, 0x61, 0x61, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x89, 0x6e, 0x78, 0x82, 0x18, 0xfe, 0x11, 0xef, 0xab, 0x88, 0x22, 0x22, 0x2d, 0x34, 0xd4, 0x11, 0x6, 0x61, 0x62, 0x63, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x4, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x89, 0x6e, 0x78, 0x82, 0x18, 0xfe, 0x11, 0xef, 0xab, 0x88, 0x22, 0x22, 0x2d, 0x34, 0xd4, 0x11, 0xa, 0x62, 0x62, 0x62, 0x62, 0x62, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x89, 0x6e, 0x78, 0x82, 0x18, 0xfe, 0x11, 0xef, 0xab, 0x88, 0x22, 0x22, 0x2d, 0x34, 0xd4, 0x11, 0xc, 0x62, 0x62, 0x62, 0x62, 0x62, 0x62, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x89, 0x6e, 0x78, 0x82, 0x18, 0xfe, 0x11, 0xef, 0xab, 0x88, 0x22, 0x22, 0x2d, 0x34, 0xd4, 0x11, 0x2, 0x78, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x2, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x89, 0x6e, 0x78, 0x82, 0x18, 0xfe, 0x11, 0xef, 0xab, 0x88, 0x22, 0x22, 0x2d, 0x34, 0xd4, 0x12, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x1, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x3, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
"896e7882-18fe-11ef-ab88-22222d34d411:1-4:aaaa:1:abc:1-3:bbbbb:1:bbbbbb:1:x:1,896e7882-18fe-11ef-ab88-22222d34d412:1-2",
},
}

for _, tc := range testcases {
e := PreviousGTIDsEvent{}
err := e.Decode(tc.input)
require.NoError(t, err)
require.Equal(t, tc.GTIDSets, e.GTIDSets)
}
}
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