parsing AUTO_INCREMENT from alter query, reading AUTO_INCREMENT from original table, applying AUTO_INCREMENT value onto ghost table if applicable and user has not specified AUTO_INCREMENT in alter statement

go/base/context.go

@@ -203,6 +203,7 @@ type MigrationContext struct {
 	OriginalTableColumns             *sql.ColumnList
 	OriginalTableVirtualColumns      *sql.ColumnList
 	OriginalTableUniqueKeys          [](*sql.UniqueKey)
+	OriginalTableAutoIncrement       uint64
 	GhostTableColumns                *sql.ColumnList
 	GhostTableVirtualColumns         *sql.ColumnList
 	GhostTableUniqueKeys             [](*sql.UniqueKey)

go/logic/applier.go

@@ -204,6 +204,25 @@ func (this *Applier) AlterGhost() error {
 	return nil
 }
 
+// AlterGhost applies `alter` statement on ghost table
+func (this *Applier) AlterGhostAutoIncrement() error {
+	query := fmt.Sprintf(`alter /* gh-ost */ table %s.%s AUTO_INCREMENT=%d`,
+		sql.EscapeName(this.migrationContext.DatabaseName),
+		sql.EscapeName(this.migrationContext.GetGhostTableName()),
+		this.migrationContext.OriginalTableAutoIncrement,
+	)
+	this.migrationContext.Log.Infof("Altering ghost table AUTO_INCREMENT value %s.%s",
+		sql.EscapeName(this.migrationContext.DatabaseName),
+		sql.EscapeName(this.migrationContext.GetGhostTableName()),
+	)
+	this.migrationContext.Log.Debugf("AUTO_INCREMENT ALTER statement: %s", query)
+	if _, err := sqlutils.ExecNoPrepare(this.db, query); err != nil {
+		return err
+	}
+	this.migrationContext.Log.Infof("Ghost table AUTO_INCREMENT altered")
+	return nil
+}
+
 // CreateChangelogTable creates the changelog table on the applier host
 func (this *Applier) CreateChangelogTable() error {
 	if err := this.DropChangelogTable(); err != nil {

go/logic/inspect.go

@@ -109,6 +109,10 @@ func (this *Inspector) InspectOriginalTable() (err error) {
 	if err != nil {
 		return err
 	}
+	this.migrationContext.OriginalTableAutoIncrement, err = this.getAutoIncrementValue(this.migrationContext.OriginalTableName)
+	if err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -589,6 +593,24 @@ func (this *Inspector) applyColumnTypes(databaseName, tableName string, columnsL
 	return err
 }
 
+// getAutoIncrementValue get's the original table's AUTO_INCREMENT value, if exists (0 value if not exists)
+func (this *Inspector) getAutoIncrementValue(tableName string) (autoIncrement uint64, err error) {
+	query := `
+    SELECT
+			AUTO_INCREMENT
+    FROM INFORMATION_SCHEMA.TABLES
+    WHERE
+			TABLES.TABLE_SCHEMA = ?
+			AND TABLES.TABLE_NAME = ?
+			AND AUTO_INCREMENT IS NOT NULL
+  `
+	err = sqlutils.QueryRowsMap(this.db, query, func(m sqlutils.RowMap) error {
+		autoIncrement = m.GetUint64("AUTO_INCREMENT")
+		return nil
+	}, this.migrationContext.DatabaseName, tableName)
+	return autoIncrement, err
+}
+
 // getCandidateUniqueKeys investigates a table and returns the list of unique keys
 // candidate for chunking
 func (this *Inspector) getCandidateUniqueKeys(tableName string) (uniqueKeys [](*sql.UniqueKey), err error) {

go/logic/migrator.go

@@ -1068,6 +1068,14 @@ func (this *Migrator) initiateApplier() error {
 		return err
 	}
 
+	if this.migrationContext.OriginalTableAutoIncrement > 0 && !this.parser.IsAutoIncrementDefined() {
+		// Original table has AUTO_INCREMENT value and the -alter statement does not indicate any override,
+		// so we should copy AUTO_INCREMENT value onto our ghost table.
+		if err := this.applier.AlterGhostAutoIncrement(); err != nil {
+			this.migrationContext.Log.Errorf("Unable to ALTER ghost table AUTO_INCREMENT value, see further error details. Bailing out")
+			return err
+		}
+	}
 	this.applier.WriteChangelogState(string(GhostTableMigrated))
 	go this.applier.InitiateHeartbeat()
 	return nil

go/sql/parser.go

@@ -16,6 +16,7 @@ var (
 	renameColumnRegexp                   = regexp.MustCompile(`(?i)\bchange\s+(column\s+|)([\S]+)\s+([\S]+)\s+`)
 	dropColumnRegexp                     = regexp.MustCompile(`(?i)\bdrop\s+(column\s+|)([\S]+)$`)
 	renameTableRegexp                    = regexp.MustCompile(`(?i)\brename\s+(to|as)\s+`)
+	autoIncrementRegexp                  = regexp.MustCompile(`(?i)\bauto_increment[\s]*=[\s]*([0-9]+)`)
 	alterTableExplicitSchemaTableRegexps = []*regexp.Regexp{
 		// ALTER TABLE `scm`.`tbl` something
 		regexp.MustCompile(`(?i)\balter\s+table\s+` + "`" + `([^` + "`" + `]+)` + "`" + `[.]` + "`" + `([^` + "`" + `]+)` + "`" + `\s+(.*$)`),
@@ -35,9 +36,10 @@ var (
 )
 
 type AlterTableParser struct {
-	columnRenameMap map[string]string
+	columnRenameMap        map[string]string
-	droppedColumns  map[string]bool
+	droppedColumns         map[string]bool
-	isRenameTable   bool
+	isRenameTable          bool
+	isAutoIncrementDefined bool
 
 	alterStatementOptions string
 	alterTokens           []string
@@ -122,6 +124,12 @@ func (this *AlterTableParser) parseAlterToken(alterToken string) (err error) {
 			this.isRenameTable = true
 		}
 	}
+	{
+		// auto_increment
+		if autoIncrementRegexp.MatchString(alterToken) {
+			this.isAutoIncrementDefined = true
+		}
+	}
 	return nil
 }
 
@@ -173,6 +181,11 @@ func (this *AlterTableParser) DroppedColumnsMap() map[string]bool {
 func (this *AlterTableParser) IsRenameTable() bool {
 	return this.isRenameTable
 }
+
+func (this *AlterTableParser) IsAutoIncrementDefined() bool {
+	return this.isAutoIncrementDefined
+}
+
 func (this *AlterTableParser) GetExplicitSchema() string {
 	return this.explicitSchema
 }

go/sql/parser_test.go

@@ -24,6 +24,7 @@ func TestParseAlterStatement(t *testing.T) {
 	test.S(t).ExpectNil(err)
 	test.S(t).ExpectEquals(parser.alterStatementOptions, statement)
 	test.S(t).ExpectFalse(parser.HasNonTrivialRenames())
+	test.S(t).ExpectFalse(parser.IsAutoIncrementDefined())
 }
 
 func TestParseAlterStatementTrivialRename(t *testing.T) {
@@ -33,10 +34,31 @@ func TestParseAlterStatementTrivialRename(t *testing.T) {
 	test.S(t).ExpectNil(err)
 	test.S(t).ExpectEquals(parser.alterStatementOptions, statement)
 	test.S(t).ExpectFalse(parser.HasNonTrivialRenames())
+	test.S(t).ExpectFalse(parser.IsAutoIncrementDefined())
 	test.S(t).ExpectEquals(len(parser.columnRenameMap), 1)
 	test.S(t).ExpectEquals(parser.columnRenameMap["ts"], "ts")
 }
 
+func TestParseAlterStatementWithAutoIncrement(t *testing.T) {
+
+	statements := []string{
+		"auto_increment=7",
+		"auto_increment = 7",
+		"AUTO_INCREMENT = 71",
+		"add column t int, change ts ts timestamp, auto_increment=7 engine=innodb",
+		"add column t int, change ts ts timestamp, auto_increment =7 engine=innodb",
+		"add column t int, change ts ts timestamp, AUTO_INCREMENT = 7 engine=innodb",
+		"add column t int, change ts ts timestamp, engine=innodb auto_increment=73425",
+	}
+	for _, statement := range statements {
+		parser := NewAlterTableParser()
+		err := parser.ParseAlterStatement(statement)
+		test.S(t).ExpectNil(err)
+		test.S(t).ExpectEquals(parser.alterStatementOptions, statement)
+		test.S(t).ExpectTrue(parser.IsAutoIncrementDefined())
+	}
+}
+
 func TestParseAlterStatementTrivialRenames(t *testing.T) {
 	statement := "add column t int, change ts ts timestamp, CHANGE f `f` float, engine=innodb"
 	parser := NewAlterTableParser()
@@ -44,6 +66,7 @@ func TestParseAlterStatementTrivialRenames(t *testing.T) {
 	test.S(t).ExpectNil(err)
 	test.S(t).ExpectEquals(parser.alterStatementOptions, statement)
 	test.S(t).ExpectFalse(parser.HasNonTrivialRenames())
+	test.S(t).ExpectFalse(parser.IsAutoIncrementDefined())
 	test.S(t).ExpectEquals(len(parser.columnRenameMap), 2)
 	test.S(t).ExpectEquals(parser.columnRenameMap["ts"], "ts")
 	test.S(t).ExpectEquals(parser.columnRenameMap["f"], "f")
@@ -64,6 +87,7 @@ func TestParseAlterStatementNonTrivial(t *testing.T) {
 		parser := NewAlterTableParser()
 		err := parser.ParseAlterStatement(statement)
 		test.S(t).ExpectNil(err)
+		test.S(t).ExpectFalse(parser.IsAutoIncrementDefined())
 		test.S(t).ExpectEquals(parser.alterStatementOptions, statement)
 		renames := parser.GetNonTrivialRenames()
 		test.S(t).ExpectEquals(len(renames), 2)