Foreign Keys: DELETE planning

go/test/endtoend/vtgate/foreignkey/fk_test.go

@@ -34,18 +34,51 @@ func TestInsertions(t *testing.T) {
 
  // Verify that inserting data into a table that has shard scoped foreign keys works.
  utils.Exec(t, conn, `insert into t2(id, col) values (100, 125), (1, 132)`)
+
  // Verify that insertion fails if the data doesn't follow the fk constraint.
  _, err := utils.ExecAllowError(t, conn, `insert into t2(id, col) values (1310, 125)`)
  require.ErrorContains(t, err, "Cannot add or update a child row: a foreign key constraint fails")
+
  // Verify that insertion fails if the table has cross-shard foreign keys (even if the data follows the constraints).
  _, err = utils.ExecAllowError(t, conn, `insert into t3(id, col) values (100, 100)`)
  require.ErrorContains(t, err, "VT12002: unsupported: cross-shard foreign keys")
 
  // insert some data in a table with multicol vindex.
  utils.Exec(t, conn, `insert into multicol_tbl1(cola, colb, colc, msg) values (100, 'a', 'b', 'msg'), (101, 'c', 'd', 'msg2')`)
+
  // Verify that inserting data into a table that has shard scoped multi-column foreign keys works.
  utils.Exec(t, conn, `insert into multicol_tbl2(cola, colb, colc, msg) values (100, 'a', 'b', 'msg3')`)
+
  // Verify that insertion fails if the data doesn't follow the fk constraint.
  _, err = utils.ExecAllowError(t, conn, `insert into multicol_tbl2(cola, colb, colc, msg) values (103, 'c', 'd', 'msg2')`)
  require.ErrorContains(t, err, "Cannot add or update a child row: a foreign key constraint fails")
 }
+
+// TestDeletions tests that deletions work as expected when foreign key management is enabled in Vitess.
+func TestDeletions(t *testing.T) {
+ conn, closer := start(t)
+ defer closer()
+
+ // insert some data.
+ utils.Exec(t, conn, `insert into t1(id, col) values (100, 123),(10, 12),(1, 13),(1000, 1234)`)
+ utils.Exec(t, conn, `insert into t2(id, col) values (100, 125), (1, 132)`)
+ utils.Exec(t, conn, `insert into t4(id, col) values (1, 321)`)
+ utils.Exec(t, conn, `insert into multicol_tbl1(cola, colb, colc, msg) values (100, 'a', 'b', 'msg'), (101, 'c', 'd', 'msg2')`)
+ utils.Exec(t, conn, `insert into multicol_tbl2(cola, colb, colc, msg) values (100, 'a', 'b', 'msg3')`)
+
+ // child foreign key is shard scoped. Query will fail at mysql due to On Delete Restrict.
+ _, err := utils.ExecAllowError(t, conn, `delete from t2 where col = 132`)
+ require.ErrorContains(t, err, "Cannot delete or update a parent row: a foreign key constraint fails")
+
+ // child row does not exist so query will succeed.
+ qr := utils.Exec(t, conn, `delete from t2 where col = 125`)
+ require.EqualValues(t, 1, qr.RowsAffected)
+
+ // table's child foreign key has cross shard fk, so query will fail at vtgate.
+ _, err = utils.ExecAllowError(t, conn, `delete from t1 where id = 42`)
+ require.ErrorContains(t, err, "VT12002: unsupported: foreign keys management at vitess (errno 1235) (sqlstate 42000)")
+
+ // child foreign key is cascade, so query will fail at vtgate.
+ _, err = utils.ExecAllowError(t, conn, `delete from multicol_tbl1 where cola = 100`)
+ require.ErrorContains(t, err, "VT12002: unsupported: foreign keys management at vitess (errno 1235) (sqlstate 42000)")
+}

go/test/endtoend/vtgate/foreignkey/main_test.go

@@ -90,10 +90,16 @@ func start(t *testing.T) (*mysql.Conn, func()) {
  require.NoError(t, err)
 
  deleteAll := func() {
- tables := []string{"t3", "t2", "t1", "multicol_tbl2", "multicol_tbl1"}
+ _ = utils.Exec(t, conn, "use `ks/-80`")
+ tables := []string{"t4", "t3", "t2", "t1", "multicol_tbl2", "multicol_tbl1"}
  for _, table := range tables {
  _ = utils.Exec(t, conn, "delete from "+table)
  }
+ _ = utils.Exec(t, conn, "use `ks/80-`")
+ for _, table := range tables {
+ _ = utils.Exec(t, conn, "delete from "+table)
+ }
+ _ = utils.Exec(t, conn, "use `ks`")
  }
 
  deleteAll()

go/test/endtoend/vtgate/foreignkey/sharded_schema.sql

@@ -10,15 +10,15 @@ create table t2
  id bigint,
  col bigint,
  primary key (id),
- foreign key (id) references t1 (id)
+ foreign key (id) references t1 (id) on delete restrict
 ) Engine = InnoDB;
 
 create table t3
 (
  id bigint,
  col bigint,
  primary key (id),
- foreign key (col) references t1 (id)
+ foreign key (col) references t1 (id) on delete restrict
 ) Engine = InnoDB;
 
 create table multicol_tbl1
@@ -37,5 +37,13 @@ create table multicol_tbl2
  colc varchar(50),
  msg varchar(50),
  primary key (cola, colb, colc),
- foreign key (cola, colb, colc) references multicol_tbl1 (cola, colb, colc)
+ foreign key (cola, colb, colc) references multicol_tbl1 (cola, colb, colc) on delete cascade
+) Engine = InnoDB;
+
+create table t4
+(
+ id bigint,
+ col bigint,
+ primary key (id),
+ foreign key (id) references t2 (id) on delete restrict
 ) Engine = InnoDB;

go/test/endtoend/vtgate/foreignkey/sharded_vschema.json

@@ -39,6 +39,14 @@
  }
  ]
  },
+ "t4": {
+ "column_vindexes": [
+ {
+ "column": "id",
+ "name": "xxhash"
+ }
+ ]
+ },
  "multicol_tbl1": {
  "column_vindexes": [
  {

go/vt/vterrors/code.go

@@ -81,6 +81,7 @@ var (
 
  VT12001 = errorWithoutState("VT12001", vtrpcpb.Code_UNIMPLEMENTED, "unsupported: %s", "This statement is unsupported by Vitess. Please rewrite your query to use supported syntax.")
  VT12002 = errorWithoutState("VT12002", vtrpcpb.Code_UNIMPLEMENTED, "unsupported: cross-shard foreign keys", "Vitess does not support cross shard foreign keys.")
+ VT12003 = errorWithoutState("VT12002", vtrpcpb.Code_UNIMPLEMENTED, "unsupported: foreign keys management at vitess", "Vitess does not support managing foreign keys tables.")
 
  // VT13001 General Error
  VT13001 = errorWithoutState("VT13001", vtrpcpb.Code_INTERNAL, "[BUG] %s", "This error should not happen and is a bug. Please file an issue on GitHub: https://github.com/vitessio/vitess/issues/new/choose.")
@@ -145,6 +146,7 @@ var (
  VT10001,
  VT12001,
  VT12002,
+ VT12003,
  VT13001,
  VT13002,
  VT14001,

go/vt/vtgate/planbuilder/delete.go

@@ -18,6 +18,7 @@ package planbuilder
 
 import (
  querypb "vitess.io/vitess/go/vt/proto/query"
+ vschemapb "vitess.io/vitess/go/vt/proto/vschema"
  "vitess.io/vitess/go/vt/sqlparser"
  "vitess.io/vitess/go/vt/vterrors"
  "vitess.io/vitess/go/vt/vtgate/engine"
@@ -62,9 +63,11 @@ func gen4DeleteStmtPlanner(
  }
 
  if ks, tables := semTable.SingleUnshardedKeyspace(); ks != nil {
- plan := deleteUnshardedShortcut(deleteStmt, ks, tables)
- plan = pushCommentDirectivesOnPlan(plan, deleteStmt)
- return newPlanResult(plan.Primitive(), operators.QualifiedTables(ks, tables)...), nil
+ if fkManagementNotRequired(vschema, tables) {
+ plan := deleteUnshardedShortcut(deleteStmt, ks, tables)
+ plan = pushCommentDirectivesOnPlan(plan, deleteStmt)
+ return newPlanResult(plan.Primitive(), operators.QualifiedTables(ks, tables)...), nil
+ }
  }
 
  if err := checkIfDeleteSupported(deleteStmt, semTable); err != nil {
@@ -98,6 +101,24 @@ func gen4DeleteStmtPlanner(
  return newPlanResult(plan.Primitive(), operators.TablesUsed(op)...), nil
 }
 
+func fkManagementNotRequired(vschema plancontext.VSchema, vTables []*vindexes.Table) bool {
+ // Find the foreign key mode and check for any managed child foreign keys.
+ for _, vTable := range vTables {
+ ksMode, err := vschema.ForeignKeyMode(vTable.Keyspace.Name)
+ if err != nil {
+ return false
+ }
+ if ksMode != vschemapb.Keyspace_FK_MANAGED {
+ continue
+ }
+ childFks := vTable.ChildFKsNeedsHandling()
+ if len(childFks) > 0 {
+ return false
+ }
+ }
+ return true
+}
+
 func rewriteSingleTbl(del *sqlparser.Delete) (*sqlparser.Delete, error) {
  atExpr, ok := del.TableExprs[0].(*sqlparser.AliasedTableExpr)
  if !ok {

go/vt/vtgate/planbuilder/operators/ast2op.go

@@ -191,6 +191,17 @@ func createOperatorFromDelete(ctx *plancontext.PlanningContext, deleteStmt *sqlp
  Routing: routing,
  }
 
+ ksMode, err := ctx.VSchema.ForeignKeyMode(vindexTable.Keyspace.Name)
+ if err != nil {
+ return nil, err
+ }
+ if ksMode == vschemapb.Keyspace_FK_MANAGED {
+ childFks := vindexTable.ChildFKsNeedsHandling()
+ if len(childFks) > 0 {
+ return nil, vterrors.VT12003()
+ }
+ }
+
  if !vindexTable.Keyspace.Sharded {
  return route, nil
  }

go/vt/vtgate/planbuilder/plan_test.go

@@ -435,25 +435,33 @@ func loadSchema(t testing.TB, filename string, setCollation bool) *vindexes.VSch
  }
  if vschema.Keyspaces["user_fk_allow"] != nil {
  // FK from multicol_tbl2 referencing multicol_tbl1 that is shard scoped.
- err = vschema.AddForeignKey("user_fk_allow", "multicol_tbl2", createFkDefinition([]string{"colb", "cola", "x", "colc", "y"}, "multicol_tbl1", []string{"colb", "cola", "y", "colc", "x"}))
+ err = vschema.AddForeignKey("user_fk_allow", "multicol_tbl2", createFkDefinition([]string{"colb", "cola", "x", "colc", "y"}, "multicol_tbl1", []string{"colb", "cola", "y", "colc", "x"}, sqlparser.Cascade, sqlparser.Cascade))
  require.NoError(t, err)
  // FK from tbl2 referencing tbl1 that is shard scoped.
- err = vschema.AddForeignKey("user_fk_allow", "tbl2", createFkDefinition([]string{"col2"}, "tbl1", []string{"col1"}))
+ err = vschema.AddForeignKey("user_fk_allow", "tbl2", createFkDefinition([]string{"col2"}, "tbl1", []string{"col1"}, sqlparser.Restrict, sqlparser.Restrict))
  require.NoError(t, err)
  // FK from tbl3 referencing tbl1 that is not shard scoped.
- err = vschema.AddForeignKey("user_fk_allow", "tbl3", createFkDefinition([]string{"coly"}, "tbl1", []string{"col1"}))
+ err = vschema.AddForeignKey("user_fk_allow", "tbl3", createFkDefinition([]string{"coly"}, "tbl1", []string{"col1"}, sqlparser.DefaultAction, sqlparser.DefaultAction))
+ require.NoError(t, err)
+ // FK from tbl4 referencing tbl5 that is shard scoped.
+ err = vschema.AddForeignKey("user_fk_allow", "tbl4", createFkDefinition([]string{"col4"}, "tbl5", []string{"col5"}, sqlparser.SetNull, sqlparser.SetNull))
+ require.NoError(t, err)
+ // FK from tbl6 referencing tbl7 that is shard scoped.
+ err = vschema.AddForeignKey("user_fk_allow", "tbl6", createFkDefinition([]string{"col6"}, "tbl7", []string{"col7"}, sqlparser.NoAction, sqlparser.NoAction))
  require.NoError(t, err)
  }
  return vschema
 }
 
 // createFkDefinition is a helper function to create a Foreign key definition struct from the columns used in it provided as list of strings.
-func createFkDefinition(childCols []string, parentTableName string, parentCols []string) *sqlparser.ForeignKeyDefinition {
+func createFkDefinition(childCols []string, parentTableName string, parentCols []string, onUpdate, onDelete sqlparser.ReferenceAction) *sqlparser.ForeignKeyDefinition {
  return &sqlparser.ForeignKeyDefinition{
  Source: sqlparser.MakeColumns(childCols...),
  ReferenceDefinition: &sqlparser.ReferenceDefinition{
  ReferencedTable: sqlparser.NewTableName(parentTableName),
  ReferencedColumns: sqlparser.MakeColumns(parentCols...),
+ OnUpdate: onUpdate,
+ OnDelete: onDelete,
  },
  }
 }

go/vt/vtgate/planbuilder/testdata/foreignkey_cases.json

@@ -53,5 +53,42 @@
  "user_fk_allow.multicol_tbl2"
  ]
  }
+ },
+ {
+ "comment": "Delete in a table with cross-shard foreign keys disallowed",
+ "query": "delete from tbl1",
+ "plan": "VT12002: unsupported: foreign keys management at vitess"
+ },
+ {
+ "comment": "Delete in a table with shard-scoped foreign keys is allowed",
+ "query": "delete from tbl7",
+ "plan": {
+ "QueryType": "DELETE",
+ "Original": "delete from tbl7",
+ "Instructions": {
+ "OperatorType": "Delete",
+ "Variant": "Scatter",
+ "Keyspace": {
+ "Name": "user_fk_allow",
+ "Sharded": true
+ },
+ "TargetTabletType": "PRIMARY",
+ "Query": "delete from tbl7",
+ "Table": "tbl7"
+ },
+ "TablesUsed": [
+ "user_fk_allow.tbl7"
+ ]
+ }
+ },
+ {
+ "comment": "Delete in a table with shard-scoped multiple column foreign key with cascade not allowed",
+ "query": "delete from multicol_tbl1 where cola = 1 and colb = 2 and colc = 3",
+ "plan": "VT12002: unsupported: foreign keys management at vitess"
+ },
+ {
+ "comment": "Delete in a table with shard-scoped foreign keys with cascade disallowed",
+ "query": "delete from tbl5",
+ "plan": "VT12002: unsupported: foreign keys management at vitess"
  }
 ]

go/vt/vtgate/planbuilder/testdata/vschemas/schema.json

@@ -608,8 +608,7 @@
  "foreignKeyMode": "FK_MANAGED",
  "vindexes": {
  "hash_vin": {
- "type": "hash_test",
- "owner": "user"
+ "type": "hash_test"
  },
  "multicolIdx": {
  "type": "multiCol_test"
@@ -663,6 +662,38 @@
  "name": "hash_vin"
  }
  ]
+ },
+ "tbl4": {
+ "column_vindexes": [
+ {
+ "column": "col4",
+ "name": "hash_vin"
+ }
+ ]
+ },
+ "tbl5": {
+ "column_vindexes": [
+ {
+ "column": "col5",
+ "name": "hash_vin"
+ }
+ ]
+ },
+ "tbl6": {
+ "column_vindexes": [
+ {
+ "column": "col6",
+ "name": "hash_vin"
+ }
+ ]
+ },
+ "tbl7": {
+ "column_vindexes": [
+ {
+ "column": "col7",
+ "name": "hash_vin"
+ }
+ ]
  }
  }
  }