schemadiff INSTANT DDL: impossible changes on tables with `FULLTEXT…

…` index (#15725)

Signed-off-by: Shlomi Noach <[email protected]>

go/vt/schemadiff/capability.go

@@ -10,6 +10,14 @@ import (
 // alterOptionAvailableViaInstantDDL checks if the specific alter option is eligible to run via ALGORITHM=INSTANT
 // reference: https://dev.mysql.com/doc/refman/8.0/en/innodb-online-ddl-operations.html
 func alterOptionCapableOfInstantDDL(alterOption sqlparser.AlterOption, createTable *sqlparser.CreateTable, capableOf capabilities.CapableOf) (bool, error) {
+	// A table with FULLTEXT index won't support adding/removing columns instantly.
+	tableHasFulltextIndex := false
+	for _, key := range createTable.TableSpec.Indexes {
+		if key.Info.Type == sqlparser.IndexTypeFullText {
+			tableHasFulltextIndex = true
+			break
+		}
+	}
 	findColumn := func(colName string) *sqlparser.ColumnDefinition {
 		if createTable == nil {
 			return nil
@@ -42,6 +50,13 @@ func alterOptionCapableOfInstantDDL(alterOption sqlparser.AlterOption, createTab
 		}
 		return nil
 	}
+	tableIsCompressed := false
+	if opt := findTableOption("ROW_FORMAT"); opt != nil {
+		if strings.EqualFold(opt.String, "COMPRESSED") {
+			tableIsCompressed = true
+		}
+	}
+
 	isVirtualColumn := func(colName string) bool {
 		col := findColumn(colName)
 		if col == nil {
@@ -87,18 +102,28 @@ func alterOptionCapableOfInstantDDL(alterOption sqlparser.AlterOption, createTab
 		//    in another table. Which is a bit too much to compute here.
 		return false, nil
 	case *sqlparser.AddColumns:
+		if tableHasFulltextIndex {
+			// not supported if the table has a FULLTEXT index
+			return false, nil
+		}
+		// Not supported in COMPRESSED tables
+		if tableIsCompressed {
+			return false, nil
+		}
 		if opt.First || opt.After != nil {
 			// not a "last" column. Only supported as of 8.0.29
 			return capableOf(capabilities.InstantAddDropColumnFlavorCapability)
 		}
 		// Adding a *last* column is supported in 8.0
 		return capableOf(capabilities.InstantAddLastColumnFlavorCapability)
 	case *sqlparser.DropColumn:
+		if tableHasFulltextIndex {
+			// not supported if the table has a FULLTEXT index
+			return false, nil
+		}
 		// Not supported in COMPRESSED tables
-		if opt := findTableOption("ROW_FORMAT"); opt != nil {
-			if strings.EqualFold(opt.String, "COMPRESSED") {
-				return false, nil
-			}
+		if tableIsCompressed {
+			return false, nil
 		}
 		if findIndexCoveringColumn(opt.Name.Name.String()) != nil {
 			// not supported if the column is part of an index

go/vt/schemadiff/capability_test.go

@@ -61,6 +61,18 @@ func TestAlterTableCapableOfInstantDDL(t *testing.T) {
 			capableOf:                 incapableOf,
 			expectCapableOfInstantDDL: false,
 		},
+		{
+			name:                      "add column fails on COMPRESSED tables",
+			create:                    "create table t1 (id int, i1 int) row_format=compressed",
+			alter:                     "alter table t1 add column i2 int",
+			expectCapableOfInstantDDL: false,
+		},
+		{
+			name:                      "add column fails on table with FULLTEXT index",
+			create:                    "create table t(id int, name varchar(128), primary key(id), fulltext key (name))",
+			alter:                     "alter table t1 add column i2 int",
+			expectCapableOfInstantDDL: false,
+		},
 		{
 			name:                      "drop virtual column",
 			create:                    "create table t(id int, i1 int not null, i2 int generated always as (i1 + 1) virtual, primary key(id))",
@@ -97,6 +109,12 @@ func TestAlterTableCapableOfInstantDDL(t *testing.T) {
 			alter:                     "alter table t drop column i1",
 			expectCapableOfInstantDDL: false,
 		},
+		{
+			name:                      "drop column fail due to fulltext index in table",
+			create:                    "create table t(id int, i1 int not null, name varchar(128), primary key(id), fulltext key (name))",
+			alter:                     "alter table t drop column i1",
+			expectCapableOfInstantDDL: false,
+		},
 		{
 			name:                      "add two columns",
 			create:                    "create table t(id int, i1 int not null, primary key(id))",
@@ -122,6 +140,12 @@ func TestAlterTableCapableOfInstantDDL(t *testing.T) {
 			alter:                     "alter table t modify column i1 int not null default 3",
 			expectCapableOfInstantDDL: true,
 		},
+		{
+			name:                      "change a default column value on a table with FULLTEXT index",
+			create:                    "create table t(id int, i1 int not null, name varchar(128), primary key(id), fulltext key (name))",
+			alter:                     "alter table t modify column i1 int not null default 3",
+			expectCapableOfInstantDDL: true,
+		},
 		{
 			name:                      "change default column value to null",
 			create:                    "create table t(id int, i1 int not null, primary key(id))",