schemadiff: FullTextKeyStrategy, handling multiple 'ADD FULLTEXT key' alter options

go/vt/schemadiff/table.go

@@ -621,7 +621,9 @@ func (c *CreateTableEntity) TableDiff(other *CreateTableEntity, hints *DiffHints
 		Table: otherStmt.Table,
 	}
 	diffedTableCharset := ""
+	var parentAlterTableEntityDiff *AlterTableEntityDiff
 	var partitionSpecs []*sqlparser.PartitionSpec
+	var superfluousFulltextKeys []*sqlparser.AddIndexDefinition
 	{
 		t1Options := c.CreateTable.TableSpec.Options
 		t2Options := other.CreateTable.TableSpec.Options
@@ -639,7 +641,7 @@ func (c *CreateTableEntity) TableDiff(other *CreateTableEntity, hints *DiffHints
 		// ordered keys for both tables:
 		t1Keys := c.CreateTable.TableSpec.Indexes
 		t2Keys := other.CreateTable.TableSpec.Indexes
-		c.diffKeys(alterTable, t1Keys, t2Keys, hints)
+		superfluousFulltextKeys = c.diffKeys(alterTable, t1Keys, t2Keys, hints)
 	}
 	{
 		// diff constraints
@@ -668,11 +670,20 @@ func (c *CreateTableEntity) TableDiff(other *CreateTableEntity, hints *DiffHints
 			return nil, err
 		}
 	}
-	var parentAlterTableEntityDiff *AlterTableEntityDiff
 	tableSpecHasChanged := len(alterTable.AlterOptions) > 0 || alterTable.PartitionOption != nil || alterTable.PartitionSpec != nil
 	if tableSpecHasChanged {
 		parentAlterTableEntityDiff = &AlterTableEntityDiff{alterTable: alterTable, from: c, to: other}
 	}
+	for _, superfluousFulltextKey := range superfluousFulltextKeys {
+		alterTable := &sqlparser.AlterTable{
+			Table:        otherStmt.Table,
+			AlterOptions: []sqlparser.AlterOption{superfluousFulltextKey},
+		}
+		diff := &AlterTableEntityDiff{alterTable: alterTable, from: c, to: other}
+		// if we got superfluous fulltext keys, that means the table spec has changed, ie
+		// parentAlterTableEntityDiff is not nil
+		parentAlterTableEntityDiff.addSubsequentDiff(diff)
+	}
 	for _, partitionSpec := range partitionSpecs {
 		alterTable := &sqlparser.AlterTable{
 			Table:         otherStmt.Table,
@@ -1103,7 +1114,7 @@ func (c *CreateTableEntity) diffKeys(alterTable *sqlparser.AlterTable,
 	t1Keys []*sqlparser.IndexDefinition,
 	t2Keys []*sqlparser.IndexDefinition,
 	hints *DiffHints,
-) {
+) (superfluousFulltextKeys []*sqlparser.AddIndexDefinition) {
 	t1KeysMap := map[string]*sqlparser.IndexDefinition{}
 	t2KeysMap := map[string]*sqlparser.IndexDefinition{}
 	for _, key := range t1Keys {
@@ -1134,6 +1145,7 @@ func (c *CreateTableEntity) diffKeys(alterTable *sqlparser.AlterTable,
 		}
 	}
 
+	addedFulltextKeys := 0
 	for _, t2Key := range t2Keys {
 		t2KeyName := t2Key.Info.Name.String()
 		// evaluate modified & added keys:
@@ -1164,9 +1176,21 @@ func (c *CreateTableEntity) diffKeys(alterTable *sqlparser.AlterTable,
 			addKey := &sqlparser.AddIndexDefinition{
 				IndexDefinition: t2Key,
 			}
-			alterTable.AlterOptions = append(alterTable.AlterOptions, addKey)
+			addedAsSuperfluousStatement := false
+			if t2Key.Info.Fulltext {
+				if addedFulltextKeys > 0 && hints.FullTextKeyStrategy == FullTextKeyDistinctStatements {
+					// Special case: MySQL does not support multiple ADD FULLTEXT KEY statements in a single ALTER
+					superfluousFulltextKeys = append(superfluousFulltextKeys, addKey)
+					addedAsSuperfluousStatement = true
+				}
+				addedFulltextKeys++
+			}
+			if !addedAsSuperfluousStatement {
+				alterTable.AlterOptions = append(alterTable.AlterOptions, addKey)
+			}
 		}
 	}
+	return superfluousFulltextKeys
 }
 
 // indexOnlyVisibilityChange checks whether the change on an index is only

go/vt/schemadiff/table_test.go

@@ -40,6 +40,7 @@ func TestCreateTableDiff(t *testing.T) {
 		errorMsg   string
 		autoinc    int
 		rotation   int
+		fulltext   int
 		colrename  int
 		constraint int
 	}{
@@ -422,6 +423,29 @@ func TestCreateTableDiff(t *testing.T) {
 			diff:  "alter table t1 alter index i_idx invisible",
 			cdiff: "ALTER TABLE `t1` ALTER INDEX `i_idx` INVISIBLE",
 		},
+		// FULLTEXT keys
+		{
+			name:  "add one fulltext key",
+			from:  "create table t1 (id int primary key, name tinytext not null)",
+			to:    "create table t1 (id int primary key, name tinytext not null, fulltext key name_ft(name))",
+			diff:  "alter table t1 add fulltext key name_ft (`name`)",
+			cdiff: "ALTER TABLE `t1` ADD FULLTEXT KEY `name_ft` (`name`)",
+		},
+		{
+			name:   "add two fulltext keys, distinct statements",
+			from:   "create table t1 (id int primary key, name1 tinytext not null, name2 tinytext not null)",
+			to:     "create table t1 (id int primary key, name1 tinytext not null, name2 tinytext not null, fulltext key name1_ft(name1), fulltext key name2_ft(name2))",
+			diffs:  []string{"alter table t1 add fulltext key name1_ft (name1)", "alter table t1 add fulltext key name2_ft (name2)"},
+			cdiffs: []string{"ALTER TABLE `t1` ADD FULLTEXT KEY `name1_ft` (`name1`)", "ALTER TABLE `t1` ADD FULLTEXT KEY `name2_ft` (`name2`)"},
+		},
+		{
+			name:     "add two fulltext keys, unify statements",
+			from:     "create table t1 (id int primary key, name1 tinytext not null, name2 tinytext not null)",
+			to:       "create table t1 (id int primary key, name1 tinytext not null, name2 tinytext not null, fulltext key name1_ft(name1), fulltext key name2_ft(name2))",
+			fulltext: FullTextKeyUnifyStatements,
+			diff:     "alter table t1 add fulltext key name1_ft (name1), add fulltext key name2_ft (name2)",
+			cdiff:    "ALTER TABLE `t1` ADD FULLTEXT KEY `name1_ft` (`name1`), ADD FULLTEXT KEY `name2_ft` (`name2`)",
+		},
 		// CHECK constraints
 		{
 			name: "identical check constraints",
@@ -981,6 +1005,7 @@ func TestCreateTableDiff(t *testing.T) {
 			hints.RangeRotationStrategy = ts.rotation
 			hints.ConstraintNamesStrategy = ts.constraint
 			hints.ColumnRenameStrategy = ts.colrename
+			hints.FullTextKeyStrategy = ts.fulltext
 			alter, err := c.Diff(other, &hints)
 
 			require.Equal(t, len(ts.diffs), len(ts.cdiffs))

go/vt/schemadiff/types.go

@@ -81,6 +81,11 @@ const (
 	TableRenameHeuristicStatement
 )
 
+const (
+	FullTextKeyDistinctStatements = iota
+	FullTextKeyUnifyStatements
+)
+
 // DiffHints is an assortment of rules for diffing entities
 type DiffHints struct {
 	StrictIndexOrdering     bool
@@ -89,4 +94,5 @@ type DiffHints struct {
 	ConstraintNamesStrategy int
 	ColumnRenameStrategy    int
 	TableRenameStrategy     int
+	FullTextKeyStrategy     int
 }