Materialize: Add copy option to strip constraints from DDL

go/vt/wrangler/materializer.go

@@ -53,7 +53,8 @@ type materializer struct {
 }
 
 const (
-	createDDLAsCopy = "copy"
+	createDDLAsCopy               = "copy"
+	createDDLAsCopyDropConstraint = "copy:drop_constraint"
 )
 
 // MoveTables initiates moving table(s) over to another keyspace
@@ -642,7 +643,7 @@ func (mz *materializer) deploySchema(ctx context.Context) error {
 				return fmt.Errorf("target table %v does not exist and there is no create ddl defined", ts.TargetTable)
 			}
 			createDDL := ts.CreateDdl
-			if createDDL == createDDLAsCopy {
+			if createDDL == createDDLAsCopy || createDDL == createDDLAsCopyDropConstraint {
 				if ts.SourceExpression != "" {
 					// Check for table if non-empty SourceExpression.
 					sourceTableName, err := sqlparser.TableFromStatement(ts.SourceExpression)
@@ -653,24 +654,31 @@ func (mz *materializer) deploySchema(ctx context.Context) error {
 						return fmt.Errorf("source and target table names must match for copying schema: %v vs %v", sqlparser.String(sourceTableName), ts.TargetTable)
 
 					}
-
 				}
 
 				ddl, ok := sourceDDL[ts.TargetTable]
 				if !ok {
 					return fmt.Errorf("source table %v does not exist", ts.TargetTable)
 				}
+
+				if createDDL == createDDLAsCopyDropConstraint {
+					strippedDDL, err := stripTableConstraints(ddl)
+					if err != nil {
+						return err
+					}
+
+					ddl = strippedDDL
+				}
 				createDDL = ddl
 			}
 
 			applyDDLs = append(applyDDLs, createDDL)
 		}
 
 		if len(applyDDLs) > 0 {
-
 			sql := strings.Join(applyDDLs, ";\n")
 
-			log.Infof("applying schema to target tablet %v...", target.MasterAlias)
+			log.Infof("applying schema to target tablet %v, sql: %s", target.MasterAlias, sql)
 			_, err = mz.wr.tmc.ApplySchema(ctx, targetTablet.Tablet, &tmutils.SchemaChange{
 				SQL:              sql,
 				Force:            false,
@@ -686,6 +694,28 @@ func (mz *materializer) deploySchema(ctx context.Context) error {
 	})
 }
 
+func stripTableConstraints(ddl string) (string, error) {
+	ast, err := sqlparser.ParseStrictDDL(ddl)
+	if err != nil {
+		return "", err
+	}
+
+	stripConstraints := func(cursor *sqlparser.Cursor) bool {
+		switch node := cursor.Node().(type) {
+		case *sqlparser.DDL:
+			if node.TableSpec != nil {
+				node.TableSpec.Constraints = nil
+			}
+		}
+		return true
+	}
+
+	noConstraintAST := sqlparser.Rewrite(ast, stripConstraints, nil)
+	newDDL := sqlparser.String(noConstraintAST)
+
+	return newDDL, nil
+}
+
 func (mz *materializer) generateInserts(ctx context.Context) (string, error) {
 	ig := vreplication.NewInsertGenerator(binlogplayer.BlpStopped, "{{.dbname}}")
 

go/vt/wrangler/materializer_test.go

@@ -26,6 +26,7 @@ import (
 	"github.com/stretchr/testify/require"
 	"golang.org/x/net/context"
 	"vitess.io/vitess/go/sqltypes"
+	"vitess.io/vitess/go/test/utils"
 	"vitess.io/vitess/go/vt/logutil"
 	querypb "vitess.io/vitess/go/vt/proto/query"
 	tabletmanagerdatapb "vitess.io/vitess/go/vt/proto/tabletmanagerdata"
@@ -2182,3 +2183,75 @@ func TestMaterializerNoVindexInExpression(t *testing.T) {
 	err := env.wr.Materialize(context.Background(), ms)
 	assert.EqualError(t, err, "could not find vindex column c1")
 }
+
+func TestStripConstraints(t *testing.T) {
+	tcs := []struct {
+		desc string
+		ddl  string
+
+		hasErr bool
+		newDDL string
+	}{
+		{
+			desc: "constraints",
+			ddl: "CREATE TABLE `table1` (\n" +
+				"`id` int(11) NOT NULL AUTO_INCREMENT,\n" +
+				"`foreign_id` int(11) NOT NULL,\n" +
+				"`user_id` int(11) NOT NULL,\n" +
+				"PRIMARY KEY (`id`),\n" +
+				"KEY `fk_table1_ref_foreign_id` (`foreign_id`),\n" +
+				"KEY `fk_table1_ref_user_id` (`user_id`),\n" +
+				"CONSTRAINT `fk_table1_ref_foreign_id` FOREIGN KEY (`foreign_id`) REFERENCES `foreign` (`id`),\n" +
+				"CONSTRAINT `fk_table1_ref_user_id` FOREIGN KEY (`user_id`) REFERENCES `core_user` (`id`)\n" +
+				") ENGINE=InnoDB DEFAULT CHARSET=latin1;",
+
+			newDDL: "create table table1 (\n" +
+				"\tid int(11) not null auto_increment,\n" +
+				"\tforeign_id int(11) not null,\n" +
+				"\tuser_id int(11) not null,\n" +
+				"\tPRIMARY KEY (id),\n" +
+				"\tKEY fk_table1_ref_foreign_id (foreign_id),\n" +
+				"\tKEY fk_table1_ref_user_id (user_id)\n" +
+				") ENGINE=InnoDB DEFAULT CHARSET=latin1",
+
+			hasErr: false,
+		},
+		{
+			desc: "no constraints",
+			ddl: "CREATE TABLE `table1` (\n" +
+				"`id` int(11) NOT NULL AUTO_INCREMENT,\n" +
+				"`foreign_id` int(11) NOT NULL,\n" +
+				"`user_id` int(11) NOT NULL,\n" +
+				"PRIMARY KEY (`id`),\n" +
+				"KEY `fk_table1_ref_foreign_id` (`foreign_id`),\n" +
+				"KEY `fk_table1_ref_user_id` (`user_id`)\n" +
+				") ENGINE=InnoDB DEFAULT CHARSET=latin1;",
+
+			newDDL: "create table table1 (\n" +
+				"\tid int(11) not null auto_increment,\n" +
+				"\tforeign_id int(11) not null,\n" +
+				"\tuser_id int(11) not null,\n" +
+				"\tPRIMARY KEY (id),\n" +
+				"\tKEY fk_table1_ref_foreign_id (foreign_id),\n" +
+				"\tKEY fk_table1_ref_user_id (user_id)\n" +
+				") ENGINE=InnoDB DEFAULT CHARSET=latin1",
+		},
+		{
+			desc: "bad ddl has error",
+			ddl:  "bad ddl",
+
+			hasErr: true,
+		},
+	}
+
+	for _, tc := range tcs {
+		newDDL, err := stripTableConstraints(tc.ddl)
+		if tc.hasErr != (err != nil) {
+			t.Fatalf("hasErr does not match: err: %v, tc: %+v", err, tc)
+		}
+
+		if newDDL != tc.newDDL {
+			utils.MustMatch(t, tc.newDDL, newDDL, fmt.Sprintf("newDDL does not match. tc: %+v", tc))
+		}
+	}
+}