Chunk on multiple parts of the key

Author: morgo

pkg/checksum/checker.go

@@ -114,7 +114,8 @@ func (c *Checker) ChecksumChunk(trxPool *dbconn.TrxPool, chunk *table.Chunk) err
 	}
 	if chunk.LowerBound != nil {
 		c.Lock()
-		c.recentValue = chunk.LowerBound.Value
+		// For recent value we only use the first part of the key.
+		c.recentValue = chunk.LowerBound.Value[0]
 		c.Unlock()
 	}
 	c.chunker.Feedback(chunk, time.Since(startTime))

pkg/migration/runner.go

@@ -551,19 +551,19 @@ func (r *Runner) postCutoverCheck(ctx context.Context) error {
 	// Instead of checker.Run we call checker.ChecksumChunk directly
 	// since we only care about a specifically crafted chunk.
 	chunk := &table.Chunk{
-		Key: cutoverTable.KeyColumns[0],
+		Key: []string{cutoverTable.KeyColumns[0]},
 		LowerBound: &table.Boundary{
-			Value: table.Datum{
+			Value: []table.Datum{{
 				Tp:  cutoverTable.MaxValue().Tp,
 				Val: lowerBoundKey,
-			},
+			}},
 			Inclusive: true,
 		},
 		UpperBound: &table.Boundary{
-			Value: table.Datum{
+			Value: []table.Datum{{
 				Tp:  cutoverTable.MaxValue().Tp,
 				Val: upperBoundKey,
-			},
+			}},
 			Inclusive: true,
 		},
 	}

pkg/migration/runner_test.go

@@ -723,7 +723,7 @@ func TestCheckpoint(t *testing.T) {
 	// gives feedback back to table.
 	watermark, err := r.copier.GetLowWatermark()
 	assert.NoError(t, err)
-	assert.Equal(t, "{\"Key\":\"id\",\"ChunkSize\":1000,\"LowerBound\":{\"Value\": \"1001\",\"Inclusive\":true},\"UpperBound\":{\"Value\": \"2001\",\"Inclusive\":false}}", watermark)
+	assert.Equal(t, "{\"Key\":[\"id\"],\"ChunkSize\":1000,\"LowerBound\":{\"Value\": [\"1001\"],\"Inclusive\":true},\"UpperBound\":{\"Value\": [\"2001\"],\"Inclusive\":false}}", watermark)
 	// Dump a checkpoint
 	assert.NoError(t, r.dumpCheckpoint(context.TODO()))
 
@@ -750,15 +750,15 @@ func TestCheckpoint(t *testing.T) {
 
 	chunk, err := r.copier.Next4Test()
 	assert.NoError(t, err)
-	assert.Equal(t, "1001", chunk.LowerBound.Value.String())
+	assert.Equal(t, "1001", chunk.LowerBound.Value[0].String())
 	assert.NoError(t, r.copier.CopyChunk(context.TODO(), chunk))
 
 	// It's ideally not typical but you can still dump checkpoint from
 	// a restored checkpoint state. We won't have advanced anywhere from
 	// the last checkpoint because on restore, the LowerBound is taken.
 	watermark, err = r.copier.GetLowWatermark()
 	assert.NoError(t, err)
-	assert.Equal(t, "{\"Key\":\"id\",\"ChunkSize\":1000,\"LowerBound\":{\"Value\": \"1001\",\"Inclusive\":true},\"UpperBound\":{\"Value\": \"2001\",\"Inclusive\":false}}", watermark)
+	assert.Equal(t, "{\"Key\":[\"id\"],\"ChunkSize\":1000,\"LowerBound\":{\"Value\": [\"1001\"],\"Inclusive\":true},\"UpperBound\":{\"Value\": [\"2001\"],\"Inclusive\":false}}", watermark)
 	// Dump a checkpoint
 	assert.NoError(t, r.dumpCheckpoint(context.TODO()))
 
@@ -771,7 +771,7 @@ func TestCheckpoint(t *testing.T) {
 
 	watermark, err = r.copier.GetLowWatermark()
 	assert.NoError(t, err)
-	assert.Equal(t, "{\"Key\":\"id\",\"ChunkSize\":1000,\"LowerBound\":{\"Value\": \"11001\",\"Inclusive\":true},\"UpperBound\":{\"Value\": \"12001\",\"Inclusive\":false}}", watermark)
+	assert.Equal(t, "{\"Key\":[\"id\"],\"ChunkSize\":1000,\"LowerBound\":{\"Value\": [\"11001\"],\"Inclusive\":true},\"UpperBound\":{\"Value\": [\"12001\"],\"Inclusive\":false}}", watermark)
 	assert.NoError(t, r.db.Close())
 }
 
@@ -824,7 +824,7 @@ func TestCheckpointRestore(t *testing.T) {
 
 	// Now insert a fake checkpoint, this uses a known bad value
 	// from issue #125
-	watermark := "{\"Key\":\"id\",\"ChunkSize\":1000,\"LowerBound\":{\"Value\":\"53926425\",\"Inclusive\":true},\"UpperBound\":{\"Value\":\"53926425\",\"Inclusive\":false}}"
+	watermark := "{\"Key\":[\"id\"],\"ChunkSize\":1000,\"LowerBound\":{\"Value\":[\"53926425\"],\"Inclusive\":true},\"UpperBound\":{\"Value\":[\"53926425\"],\"Inclusive\":false}}"
 	binlog := r.replClient.GetBinlogApplyPosition()
 	query := fmt.Sprintf("INSERT INTO %s (low_watermark, binlog_name, binlog_pos, rows_copied, rows_copied_logical, alter_statement) VALUES (?, ?, ?, ?, ?, ?)",
 		r.checkpointTable.QuotedName)
@@ -944,7 +944,7 @@ func TestCheckpointDifferentRestoreOptions(t *testing.T) {
 
 	watermark, err := m.copier.GetLowWatermark()
 	assert.NoError(t, err)
-	assert.Equal(t, "{\"Key\":\"id\",\"ChunkSize\":1000,\"LowerBound\":{\"Value\": \"1001\",\"Inclusive\":true},\"UpperBound\":{\"Value\": \"2001\",\"Inclusive\":false}}", watermark)
+	assert.Equal(t, "{\"Key\":[\"id\"],\"ChunkSize\":1000,\"LowerBound\":{\"Value\": [\"1001\"],\"Inclusive\":true},\"UpperBound\":{\"Value\": [\"2001\"],\"Inclusive\":false}}", watermark)
 	// Dump a checkpoint
 	assert.NoError(t, m.dumpCheckpoint(context.TODO()))
 
@@ -1126,7 +1126,7 @@ func TestE2EBinlogSubscribingCompositeKey(t *testing.T) {
 	chunk, err := m.copier.Next4Test()
 	assert.NoError(t, err)
 	assert.NotNil(t, chunk)
-	assert.Equal(t, "`id1` < 1001", chunk.String())
+	assert.Equal(t, "((`id1` < 1001)\n OR (`id1` = 1001 AND `id2` < 1))", chunk.String())
 	assert.NoError(t, m.copier.CopyChunk(context.TODO(), chunk))
 
 	// Now insert some data.
@@ -1140,7 +1140,7 @@ func TestE2EBinlogSubscribingCompositeKey(t *testing.T) {
 	// Second chunk
 	chunk, err = m.copier.Next4Test()
 	assert.NoError(t, err)
-	assert.Equal(t, "`id1` >= 1001", chunk.String())
+	assert.Equal(t, "((`id1` > 1001)\n OR (`id1` = 1001 AND `id2` >= 1))", chunk.String())
 	assert.NoError(t, m.copier.CopyChunk(context.TODO(), chunk))
 
 	// Now insert some data.
@@ -1775,7 +1775,7 @@ func TestE2ERogueValues(t *testing.T) {
 	// Second chunk
 	chunk, err = m.copier.Next4Test()
 	assert.NoError(t, err)
-	assert.Equal(t, "`datetime` >= \"819 \\\". \"", chunk.String())
+	assert.Equal(t, "((`datetime` > \"819 \\\". \")\n OR (`datetime` = \"819 \\\". \" AND `col2` >= 1))", chunk.String())
 	assert.NoError(t, m.copier.CopyChunk(context.TODO(), chunk))
 
 	// Now insert some data.

pkg/row/copier_test.go

@@ -366,7 +366,7 @@ func TestCopierFromCheckpoint(t *testing.T) {
 	t1new := table.NewTableInfo(db, "test", "_copierchkpt1_new")
 	assert.NoError(t, t1new.SetInfo(context.TODO()))
 
-	lowWatermark := `{"Key":"a","ChunkSize":1,"LowerBound":{"Value":3,"Inclusive":true},"UpperBound":{"Value":4,"Inclusive":false}}`
+	lowWatermark := `{"Key":["a"],"ChunkSize":1,"LowerBound":{"Value":["3"],"Inclusive":true},"UpperBound":{"Value":["4"],"Inclusive":false}}`
 	copier, err := NewCopierFromCheckpoint(db, t1, t1new, NewCopierDefaultConfig(), lowWatermark, 3, 3)
 	assert.NoError(t, err)
 	assert.NoError(t, copier.Run(context.Background())) // works

pkg/table/README.md

@@ -45,7 +45,6 @@ To deal with large gaps, the optimistic chunker also supports a special "prefetc
 
 The following are known issues:
 
-* The composite chunker was named as such because we realized one of the main deficiencies of the optimistic chunker is _composite PRIMARY KEYs_. Despite its name, the composite chunker only chunks on the first part of the `PRIMARY KEY`. We intend to address this feature in the future.
 * Neither of the chunkers support chunking on anything other than the `PRIMARY KEY`. For our purposes, this is usually acceptable but we may have to revisit this in the future.
 * Not specifically a limitation of chunking, but some optimizations in spirit require that the `PRIMARY KEY` not have collations. Thus, we explicitly disallow `VARCHAR` primary keys in the chunker. The optimizations are very useful, which makes this a complex problem to fix. But it also appears to be the most common incompatibility issue with spirit, so we may have to reconsider this at some point.
 

pkg/table/chunk.go

@@ -9,15 +9,15 @@ import (
 // Chunk is returned by chunk.Next()
 // Applications can use it to iterate over the rows.
 type Chunk struct {
-	Key        string
+	Key        []string
 	ChunkSize  uint64
 	LowerBound *Boundary
 	UpperBound *Boundary
 }
 
 // Boundary is used by chunk for lower or upper boundary
 type Boundary struct {
-	Value     Datum
+	Value     []Datum
 	Inclusive bool
 }
 
@@ -40,14 +40,16 @@ func (c *Chunk) String() string {
 		if !c.LowerBound.Inclusive {
 			operator = OpGreaterThan
 		}
-		conds = append(conds, fmt.Sprintf("`%s` %s %s", c.Key, operator, c.LowerBound.Value))
+		str := expandRowConstructorComparison(c.Key, operator, c.LowerBound.Value)
+		conds = append(conds, str)
 	}
 	if c.UpperBound != nil {
 		operator := OpLessEqual
 		if !c.UpperBound.Inclusive {
 			operator = OpLessThan
 		}
-		conds = append(conds, fmt.Sprintf("`%s` %s %s", c.Key, operator, c.UpperBound.Value))
+		str := expandRowConstructorComparison(c.Key, operator, c.UpperBound.Value)
+		conds = append(conds, str)
 	}
 	if c.LowerBound == nil && c.UpperBound == nil {
 		conds = append(conds, "1=1")
@@ -56,55 +58,87 @@ func (c *Chunk) String() string {
 }
 
 func (c *Chunk) JSON() string {
-	return fmt.Sprintf(`{"Key":"%s","ChunkSize":%d,"LowerBound":%s,"UpperBound":%s}`,
-		c.Key,
+	return fmt.Sprintf(`{"Key":["%s"],"ChunkSize":%d,"LowerBound":%s,"UpperBound":%s}`,
+		strings.Join(c.Key, `","`),
 		c.ChunkSize,
 		c.LowerBound.JSON(),
 		c.UpperBound.JSON(),
 	)
 }
 
+// JSON encodes a boundary as JSON. The values are represented as strings,
+// to avoid JSON float behavior. See Issue #125
 func (b *Boundary) JSON() string {
-	// encode values as strings otherwise we get JSON floats
-	// which can corrupt larger values. Issue #125
-	return fmt.Sprintf(`{"Value": "%s","Inclusive":%t}`, b.Value, b.Inclusive)
+	vals := make([]string, len(b.Value))
+	for i, v := range b.Value {
+		vals[i] = fmt.Sprintf(`"%s"`, v)
+	}
+	return fmt.Sprintf(`{"Value": [%s],"Inclusive":%t}`, strings.Join(vals, ","), b.Inclusive)
+}
+
+// comparesTo returns true if the boundaries are the same.
+// It is used to compare two boundaries, such as if
+// a.Upper == b.Lower. For this reason it does not compare
+// the operator (inclusive or not)!
+func (b *Boundary) comparesTo(b2 *Boundary) bool {
+	if len(b.Value) != len(b2.Value) {
+		return false
+	}
+	for i := range b.Value {
+		if b.Value[i].Tp != b2.Value[i].Tp {
+			return false
+		}
+		if b.Value[i].Val != b2.Value[i].Val {
+			return false
+		}
+	}
+	return true
 }
 
 type JSONChunk struct {
-	Key        string
+	Key        []string
 	ChunkSize  uint64
 	LowerBound JSONBoundary
 	UpperBound JSONBoundary
 }
 
 type JSONBoundary struct {
-	Value     interface{}
+	Value     []string
 	Inclusive bool
 }
 
-func NewChunkFromJSON(jsonStr string, tp string) (*Chunk, error) {
+func jsonStrings2Datums(ti *TableInfo, keys []string, vals []string) ([]Datum, error) {
+	datums := make([]Datum, len(keys))
+	for i, str := range vals {
+		tp := ti.datumTp(keys[i])
+		datums[i] = newDatum(fmt.Sprint(str), tp)
+	}
+	return datums, nil
+}
+
+func newChunkFromJSON(ti *TableInfo, jsonStr string) (*Chunk, error) {
 	var chunk JSONChunk
 	err := json.Unmarshal([]byte(jsonStr), &chunk)
 	if err != nil {
 		return nil, err
 	}
-	lowerVal, err := newDatumFromMySQL(fmt.Sprint(chunk.LowerBound.Value), tp)
+	lowerVals, err := jsonStrings2Datums(ti, chunk.Key, chunk.LowerBound.Value)
 	if err != nil {
 		return nil, err
 	}
-	upperVal, err := newDatumFromMySQL(fmt.Sprint(chunk.UpperBound.Value), tp)
+	upperVals, err := jsonStrings2Datums(ti, chunk.Key, chunk.UpperBound.Value)
 	if err != nil {
 		return nil, err
 	}
 	return &Chunk{
 		Key:       chunk.Key,
 		ChunkSize: chunk.ChunkSize,
 		LowerBound: &Boundary{
-			Value:     lowerVal,
+			Value:     lowerVals,
 			Inclusive: chunk.LowerBound.Inclusive,
 		},
 		UpperBound: &Boundary{
-			Value:     upperVal,
+			Value:     upperVals,
 			Inclusive: chunk.UpperBound.Inclusive,
 		},
 	}, nil

pkg/table/chunk_test.go

@@ -8,37 +8,107 @@ import (
 
 func TestChunk2String(t *testing.T) {
 	chunk := &Chunk{
-		Key: "id",
+		Key: []string{"id"},
 		LowerBound: &Boundary{
-			Value:     newDatum(100, signedType),
+			Value:     []Datum{newDatum(100, signedType)},
 			Inclusive: true,
 		},
 		UpperBound: &Boundary{
-			Value:     newDatum(200, signedType),
+			Value:     []Datum{newDatum(200, signedType)},
 			Inclusive: false,
 		},
 	}
 	assert.Equal(t, "`id` >= 100 AND `id` < 200", chunk.String())
 	chunk = &Chunk{
-		Key: "id",
+		Key: []string{"id"},
 		LowerBound: &Boundary{
-			Value:     newDatum(100, signedType),
+			Value:     []Datum{newDatum(100, signedType)},
 			Inclusive: false,
 		},
 	}
 	assert.Equal(t, "`id` > 100", chunk.String())
 	chunk = &Chunk{
-		Key: "id",
+		Key: []string{"id"},
 		UpperBound: &Boundary{
-			Value:     newDatum(200, signedType),
+			Value:     []Datum{newDatum(200, signedType)},
 			Inclusive: true,
 		},
 	}
 	assert.Equal(t, "`id` <= 200", chunk.String())
 
-	// Empty chunks are possible with the trivial chunker.
+	// Empty chunks are possible with the composite chunker
 	chunk = &Chunk{
-		Key: "id",
+		Key: []string{"id"},
 	}
 	assert.Equal(t, "1=1", chunk.String())
 }
+
+func TestCompositeChunks(t *testing.T) {
+	chunk := &Chunk{
+		Key: []string{"id1", "id2"},
+		LowerBound: &Boundary{
+			Value:     []Datum{newDatum(100, signedType), newDatum(200, signedType)},
+			Inclusive: false,
+		},
+		UpperBound: &Boundary{
+			Value:     []Datum{newDatum(100, signedType), newDatum(300, signedType)},
+			Inclusive: false,
+		},
+	}
+	assert.Equal(t, "((`id1` > 100)\n OR (`id1` = 100 AND `id2` > 200)) AND ((`id1` < 100)\n OR (`id1` = 100 AND `id2` < 300))", chunk.String())
+	// 4 parts to the key - pretty unlikely.
+	chunk = &Chunk{
+		Key: []string{"id1", "id2", "id3", "id4"},
+		LowerBound: &Boundary{
+			Value:     []Datum{newDatum(100, signedType), newDatum(200, signedType), newDatum(200, signedType), newDatum(200, signedType)},
+			Inclusive: true,
+		},
+		UpperBound: &Boundary{
+			Value:     []Datum{newDatum(101, signedType), newDatum(12, signedType), newDatum(123, signedType), newDatum(1, signedType)},
+			Inclusive: false,
+		},
+	}
+	assert.Equal(t, "((`id1` > 100)\n OR (`id1` = 100 AND `id2` > 200)\n OR (`id1` = 100 AND `id2` = 200 AND `id3` > 200)\n OR (`id1` = 100 AND `id2` = 200 AND `id3` = 200 AND `id4` >= 200)) AND ((`id1` < 101)\n OR (`id1` = 101 AND `id2` < 12)\n OR (`id1` = 101 AND `id2` = 12 AND `id3` < 123)\n OR (`id1` = 101 AND `id2` = 12 AND `id3` = 123 AND `id4` < 1))", chunk.String())
+	// A possible scenario when chunking on a non primary key is possible:
+	chunk = &Chunk{
+		Key: []string{"status", "id"},
+		LowerBound: &Boundary{
+			Value:     []Datum{newDatum("ARCHIVED", binaryType), newDatum(1234, signedType)},
+			Inclusive: true,
+		},
+		UpperBound: &Boundary{
+			Value:     []Datum{newDatum("ARCHIVED", binaryType), newDatum(5412, signedType)},
+			Inclusive: false,
+		},
+	}
+	assert.Equal(t, "((`status` > \"ARCHIVED\")\n OR (`status` = \"ARCHIVED\" AND `id` >= 1234)) AND ((`status` < \"ARCHIVED\")\n OR (`status` = \"ARCHIVED\" AND `id` < 5412))", chunk.String())
+}
+
+func TestComparesTo(t *testing.T) {
+	b1 := &Boundary{
+		Value:     []Datum{newDatum(200, signedType)},
+		Inclusive: true,
+	}
+	b2 := &Boundary{
+		Value:     []Datum{newDatum(200, signedType)},
+		Inclusive: true,
+	}
+	assert.True(t, b1.comparesTo(b2))
+	b2.Inclusive = false              // change operator
+	assert.True(t, b1.comparesTo(b2)) // still compares
+	b2.Value = []Datum{newDatum(300, signedType)}
+	assert.False(t, b1.comparesTo(b2))
+
+	// Compound values.
+	b1 = &Boundary{
+		Value:     []Datum{newDatum(200, signedType), newDatum(300, signedType)},
+		Inclusive: true,
+	}
+	b2 = &Boundary{
+		Value:     []Datum{newDatum(200, signedType), newDatum(300, signedType)},
+		Inclusive: true,
+	}
+	assert.True(t, b1.comparesTo(b2))
+	b2.Value = []Datum{newDatum(200, signedType), newDatum(400, signedType)}
+	assert.False(t, b1.comparesTo(b2))
+}