func getDescriptor(
txn *client.Txn, plainKey sqlbase.DescriptorKey, descriptor sqlbase.DescriptorProto,
) (bool, error) {
gr, err := txn.Get(plainKey.Key())
if err != nil {
return false, err
}
if !gr.Exists() {
return false, nil
}
descKey := sqlbase.MakeDescMetadataKey(sqlbase.ID(gr.ValueInt()))
desc := &sqlbase.Descriptor{}
if err := txn.GetProto(descKey, desc); err != nil {
return false, err
}
switch t := descriptor.(type) {
case *sqlbase.TableDescriptor:
table := desc.GetTable()
if table == nil {
return false, errors.Errorf("%q is not a table", plainKey.Name())
}
table.MaybeUpgradeFormatVersion()
// TODO(dan): Write the upgraded TableDescriptor back to kv. This will break
// the ability to use a previous version of cockroach with the on-disk data,
// but it's worth it to avoid having to do the upgrade every time the
// descriptor is fetched. Our current test for this enforces compatibility
// backward and forward, so that'll have to be extended before this is done.
if err := table.Validate(txn); err != nil {
return false, err
}
*t = *table
case *sqlbase.DatabaseDescriptor:
database := desc.GetDatabase()
if database == nil {
return false, errors.Errorf("%q is not a database", plainKey.Name())
}
if err := database.Validate(); err != nil {
return false, err
}
*t = *database
}
return true, nil
}
// createDescriptor implements the DescriptorAccessor interface.
func (p *planner) createDescriptor(
plainKey sqlbase.DescriptorKey, descriptor sqlbase.DescriptorProto, ifNotExists bool,
) (bool, error) {
idKey := plainKey.Key()
if exists, err := p.descExists(idKey); err == nil && exists {
if ifNotExists {
// Noop.
return false, nil
}
// Key exists, but we don't want it to: error out.
switch descriptor.TypeName() {
case "database":
return false, sqlbase.NewDatabaseAlreadyExistsError(plainKey.Name())
case "table", "view":
return false, sqlbase.NewRelationAlreadyExistsError(plainKey.Name())
default:
return false, descriptorAlreadyExistsErr{descriptor, plainKey.Name()}
}
} else if err != nil {
return false, err
}
id, err := GenerateUniqueDescID(p.txn)
if err != nil {
return false, err
}
return true, p.createDescriptorWithID(idKey, id, descriptor)
}