/
ddl.go
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/
ddl.go
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package planbuilder
import (
"vitess.io/vitess/go/vt/key"
vtrpcpb "vitess.io/vitess/go/vt/proto/vtrpc"
"vitess.io/vitess/go/vt/sqlparser"
"vitess.io/vitess/go/vt/vterrors"
"vitess.io/vitess/go/vt/vtgate/engine"
"vitess.io/vitess/go/vt/vtgate/planbuilder/plancontext"
"vitess.io/vitess/go/vt/vtgate/vindexes"
)
// Error messages for CreateView queries
const (
ViewDifferentKeyspace string = "Select query does not belong to the same keyspace as the view statement"
ViewComplex string = "Complex select queries are not supported in create or alter view statements"
DifferentDestinations string = "Tables or Views specified in the query do not belong to the same destination"
)
type fkStrategy int
const (
fkAllow fkStrategy = iota
fkDisallow
)
var fkStrategyMap = map[string]fkStrategy{
"allow": fkAllow,
"disallow": fkDisallow,
}
type fkContraint struct {
found bool
}
func (fk *fkContraint) FkWalk(node sqlparser.SQLNode) (kontinue bool, err error) {
switch node.(type) {
case *sqlparser.CreateTable, *sqlparser.AlterTable,
*sqlparser.TableSpec, *sqlparser.AddConstraintDefinition, *sqlparser.ConstraintDefinition:
return true, nil
case *sqlparser.ForeignKeyDefinition:
fk.found = true
}
return false, nil
}
// buildGeneralDDLPlan builds a general DDL plan, which can be either normal DDL or online DDL.
// The two behave compeltely differently, and have two very different primitives.
// We want to be able to dynamically choose between normal/online plans according to Session settings.
// However, due to caching of plans, we're unable to make that choice right now. In this function we don't have
// a session context. It's only when we Execute() the primitive that we have that context.
// This is why we return a compound primitive (DDL) which contains fully populated primitives (Send & OnlineDDL),
// and which chooses which of the two to invoke at runtime.
func buildGeneralDDLPlan(sql string, ddlStatement sqlparser.DDLStatement, reservedVars *sqlparser.ReservedVars, vschema plancontext.VSchema, enableOnlineDDL, enableDirectDDL bool) (*planResult, error) {
if vschema.Destination() != nil {
return buildByPassDDLPlan(sql, vschema)
}
normalDDLPlan, onlineDDLPlan, err := buildDDLPlans(sql, ddlStatement, reservedVars, vschema, enableOnlineDDL, enableDirectDDL)
if err != nil {
return nil, err
}
if ddlStatement.IsTemporary() {
err := vschema.ErrorIfShardedF(normalDDLPlan.Keyspace, "temporary table", "Temporary table not supported in sharded database %s", normalDDLPlan.Keyspace.Name)
if err != nil {
return nil, err
}
onlineDDLPlan = nil // emptying this so it does not accidentally gets used somewhere
}
eddl := &engine.DDL{
Keyspace: normalDDLPlan.Keyspace,
SQL: normalDDLPlan.Query,
DDL: ddlStatement,
NormalDDL: normalDDLPlan,
OnlineDDL: onlineDDLPlan,
DirectDDLEnabled: enableDirectDDL,
OnlineDDLEnabled: enableOnlineDDL,
CreateTempTable: ddlStatement.IsTemporary(),
}
tc := &tableCollector{}
for _, tbl := range ddlStatement.AffectedTables() {
tc.addASTTable(normalDDLPlan.Keyspace.Name, tbl)
}
return newPlanResult(eddl, tc.getTables()...), nil
}
func buildByPassDDLPlan(sql string, vschema plancontext.VSchema) (*planResult, error) {
keyspace, err := vschema.DefaultKeyspace()
if err != nil {
return nil, err
}
send := &engine.Send{
Keyspace: keyspace,
TargetDestination: vschema.Destination(),
Query: sql,
}
return newPlanResult(send), nil
}
func buildDDLPlans(sql string, ddlStatement sqlparser.DDLStatement, reservedVars *sqlparser.ReservedVars, vschema plancontext.VSchema, enableOnlineDDL, enableDirectDDL bool) (*engine.Send, *engine.OnlineDDL, error) {
var destination key.Destination
var keyspace *vindexes.Keyspace
var err error
switch ddl := ddlStatement.(type) {
case *sqlparser.AlterTable, *sqlparser.TruncateTable:
err = checkFKError(vschema, ddlStatement)
if err != nil {
return nil, nil, err
}
// For Alter Table and other statements, the table must already exist
// We should find the target of the query from this tables location
destination, keyspace, err = findTableDestinationAndKeyspace(vschema, ddlStatement)
case *sqlparser.CreateView:
destination, keyspace, err = buildCreateView(vschema, ddl, reservedVars, enableOnlineDDL, enableDirectDDL)
case *sqlparser.AlterView:
destination, keyspace, err = buildAlterView(vschema, ddl, reservedVars, enableOnlineDDL, enableDirectDDL)
case *sqlparser.CreateTable:
err = checkFKError(vschema, ddlStatement)
if err != nil {
return nil, nil, err
}
destination, keyspace, _, err = vschema.TargetDestination(ddlStatement.GetTable().Qualifier.String())
if err != nil {
return nil, nil, err
}
// Remove the keyspace name as the database name might be different.
ddlStatement.SetTable("", ddlStatement.GetTable().Name.String())
case *sqlparser.DropView, *sqlparser.DropTable:
destination, keyspace, err = buildDropViewOrTable(vschema, ddlStatement)
case *sqlparser.RenameTable:
destination, keyspace, err = buildRenameTable(vschema, ddl)
default:
return nil, nil, vterrors.Errorf(vtrpcpb.Code_INTERNAL, "[BUG] unexpected ddl statement type: %T", ddlStatement)
}
if err != nil {
return nil, nil, err
}
if destination == nil {
destination = key.DestinationAllShards{}
}
query := sql
// If the query is fully parsed, generate the query from the ast. Otherwise, use the original query
if ddlStatement.IsFullyParsed() {
query = sqlparser.String(ddlStatement)
}
return &engine.Send{
Keyspace: keyspace,
TargetDestination: destination,
Query: query,
IsDML: false,
SingleShardOnly: false,
}, &engine.OnlineDDL{
Keyspace: keyspace,
TargetDestination: destination,
DDL: ddlStatement,
SQL: query,
}, nil
}
func checkFKError(vschema plancontext.VSchema, ddlStatement sqlparser.DDLStatement) error {
if fkStrategyMap[vschema.ForeignKeyMode()] == fkDisallow {
fk := &fkContraint{}
_ = sqlparser.Walk(fk.FkWalk, ddlStatement)
if fk.found {
return vterrors.Errorf(vtrpcpb.Code_ABORTED, "foreign key constraints are not allowed, see https://vitess.io/blog/2021-06-15-online-ddl-why-no-fk/")
}
}
return nil
}
func findTableDestinationAndKeyspace(vschema plancontext.VSchema, ddlStatement sqlparser.DDLStatement) (key.Destination, *vindexes.Keyspace, error) {
var table *vindexes.Table
var destination key.Destination
var keyspace *vindexes.Keyspace
var err error
table, _, _, _, destination, err = vschema.FindTableOrVindex(ddlStatement.GetTable())
if err != nil {
_, isNotFound := err.(vindexes.NotFoundError)
if !isNotFound {
return nil, nil, err
}
}
if table == nil {
destination, keyspace, _, err = vschema.TargetDestination(ddlStatement.GetTable().Qualifier.String())
if err != nil {
return nil, nil, err
}
ddlStatement.SetTable("", ddlStatement.GetTable().Name.String())
} else {
keyspace = table.Keyspace
ddlStatement.SetTable("", table.Name.String())
}
return destination, keyspace, nil
}
func buildAlterView(vschema plancontext.VSchema, ddl *sqlparser.AlterView, reservedVars *sqlparser.ReservedVars, enableOnlineDDL, enableDirectDDL bool) (key.Destination, *vindexes.Keyspace, error) {
// For Alter View, we require that the view exist and the select query can be satisfied within the keyspace itself
// We should remove the keyspace name from the table name, as the database name in MySQL might be different than the keyspace name
destination, keyspace, err := findTableDestinationAndKeyspace(vschema, ddl)
if err != nil {
return nil, nil, err
}
selectPlan, err := createInstructionFor(sqlparser.String(ddl.Select), ddl.Select, reservedVars, vschema, enableOnlineDDL, enableDirectDDL)
if err != nil {
return nil, nil, err
}
isRoutePlan, keyspaceName, opCode := tryToGetRoutePlan(selectPlan.primitive)
if !isRoutePlan {
return nil, nil, vterrors.New(vtrpcpb.Code_UNIMPLEMENTED, ViewComplex)
}
if keyspace.Name != keyspaceName {
return nil, nil, vterrors.New(vtrpcpb.Code_UNIMPLEMENTED, ViewDifferentKeyspace)
}
if opCode != engine.Unsharded && opCode != engine.EqualUnique && opCode != engine.Scatter {
return nil, nil, vterrors.New(vtrpcpb.Code_UNIMPLEMENTED, ViewComplex)
}
_ = sqlparser.Rewrite(ddl.Select, func(cursor *sqlparser.Cursor) bool {
switch tableName := cursor.Node().(type) {
case sqlparser.TableName:
cursor.Replace(sqlparser.TableName{
Name: tableName.Name,
})
}
return true
}, nil)
return destination, keyspace, nil
}
func buildCreateView(vschema plancontext.VSchema, ddl *sqlparser.CreateView, reservedVars *sqlparser.ReservedVars, enableOnlineDDL, enableDirectDDL bool) (key.Destination, *vindexes.Keyspace, error) {
// For Create View, we require that the keyspace exist and the select query can be satisfied within the keyspace itself
// We should remove the keyspace name from the table name, as the database name in MySQL might be different than the keyspace name
destination, keyspace, _, err := vschema.TargetDestination(ddl.ViewName.Qualifier.String())
if err != nil {
return nil, nil, err
}
ddl.ViewName.Qualifier = sqlparser.NewIdentifierCS("")
selectPlan, err := createInstructionFor(sqlparser.String(ddl.Select), ddl.Select, reservedVars, vschema, enableOnlineDDL, enableDirectDDL)
if err != nil {
return nil, nil, err
}
isRoutePlan, keyspaceName, opCode := tryToGetRoutePlan(selectPlan.primitive)
if !isRoutePlan {
return nil, nil, vterrors.New(vtrpcpb.Code_UNIMPLEMENTED, ViewComplex)
}
if keyspace.Name != keyspaceName {
return nil, nil, vterrors.New(vtrpcpb.Code_UNIMPLEMENTED, ViewDifferentKeyspace)
}
if opCode != engine.Unsharded && opCode != engine.EqualUnique && opCode != engine.Scatter {
return nil, nil, vterrors.New(vtrpcpb.Code_UNIMPLEMENTED, ViewComplex)
}
_ = sqlparser.Rewrite(ddl.Select, func(cursor *sqlparser.Cursor) bool {
switch tableName := cursor.Node().(type) {
case sqlparser.TableName:
cursor.Replace(sqlparser.TableName{
Name: tableName.Name,
})
}
return true
}, nil)
return destination, keyspace, nil
}
func buildDropViewOrTable(vschema plancontext.VSchema, ddlStatement sqlparser.DDLStatement) (key.Destination, *vindexes.Keyspace, error) {
var destination key.Destination
var keyspace *vindexes.Keyspace
for i, tab := range ddlStatement.GetFromTables() {
var destinationTab key.Destination
var keyspaceTab *vindexes.Keyspace
var table *vindexes.Table
var err error
table, _, _, _, destinationTab, err = vschema.FindTableOrVindex(tab)
if err != nil {
_, isNotFound := err.(vindexes.NotFoundError)
if !isNotFound {
return nil, nil, err
}
}
if table == nil {
destinationTab, keyspaceTab, _, err = vschema.TargetDestination(tab.Qualifier.String())
if err != nil {
return nil, nil, err
}
ddlStatement.GetFromTables()[i] = sqlparser.TableName{
Name: tab.Name,
}
} else {
keyspaceTab = table.Keyspace
ddlStatement.GetFromTables()[i] = sqlparser.TableName{
Name: table.Name,
}
}
if destination == nil && keyspace == nil {
destination = destinationTab
keyspace = keyspaceTab
}
if destination != destinationTab || keyspace != keyspaceTab {
return nil, nil, vterrors.New(vtrpcpb.Code_UNIMPLEMENTED, DifferentDestinations)
}
}
return destination, keyspace, nil
}
func buildRenameTable(vschema plancontext.VSchema, renameTable *sqlparser.RenameTable) (key.Destination, *vindexes.Keyspace, error) {
var destination key.Destination
var keyspace *vindexes.Keyspace
for _, tabPair := range renameTable.TablePairs {
var destinationFrom key.Destination
var keyspaceFrom *vindexes.Keyspace
var table *vindexes.Table
var err error
table, _, _, _, destinationFrom, err = vschema.FindTableOrVindex(tabPair.FromTable)
if err != nil {
_, isNotFound := err.(vindexes.NotFoundError)
if !isNotFound {
return nil, nil, err
}
}
if table == nil {
destinationFrom, keyspaceFrom, _, err = vschema.TargetDestination(tabPair.FromTable.Qualifier.String())
if err != nil {
return nil, nil, err
}
tabPair.FromTable = sqlparser.TableName{
Name: tabPair.FromTable.Name,
}
} else {
keyspaceFrom = table.Keyspace
tabPair.FromTable = sqlparser.TableName{
Name: table.Name,
}
}
if tabPair.ToTable.Qualifier.String() != "" {
_, keyspaceTo, _, err := vschema.TargetDestination(tabPair.ToTable.Qualifier.String())
if err != nil {
return nil, nil, err
}
if keyspaceTo.Name != keyspaceFrom.Name {
return nil, nil, vterrors.NewErrorf(vtrpcpb.Code_INVALID_ARGUMENT, vterrors.ForbidSchemaChange, "Changing schema from '%s' to '%s' is not allowed", keyspaceFrom.Name, keyspaceTo.Name)
}
tabPair.ToTable = sqlparser.TableName{
Name: tabPair.ToTable.Name,
}
}
if destination == nil && keyspace == nil {
destination = destinationFrom
keyspace = keyspaceFrom
}
if destination != destinationFrom || keyspace != keyspaceFrom {
return nil, nil, vterrors.New(vtrpcpb.Code_UNIMPLEMENTED, DifferentDestinations)
}
}
return destination, keyspace, nil
}
func tryToGetRoutePlan(selectPlan engine.Primitive) (valid bool, keyspaceName string, opCode engine.Opcode) {
switch plan := selectPlan.(type) {
case *engine.Route:
return true, plan.Keyspace.Name, plan.Opcode
case engine.Gen4Comparer:
return tryToGetRoutePlan(plan.GetGen4Primitive())
default:
return false, "", engine.Opcode(0)
}
}