Method upgradeType

postgres/parser/types/types.go:1950–2137

upgradeType assumes its input was just unmarshaled from bytes that may have been serialized by any previous version of CRDB. It upgrades the object according to the requirements of the latest version by remapping fields and setting required values. This is necessary to preserve backwards- compatibil

()

// setting required values. This is necessary to preserve backwards-
// compatibility with older formats (e.g. restoring database from old backup).
func (t *T) upgradeType() error {
	switch t.Family() {
	case IntFamily:
		// Check VisibleType field that was populated in previous versions.
		switch t.InternalType.VisibleType {
		case visibleSMALLINT:
			t.InternalType.Width = 16
			t.InternalType.Oid = oid.T_int2
		case visibleINTEGER:
			t.InternalType.Width = 32
			t.InternalType.Oid = oid.T_int4
		case visibleBIGINT:
			t.InternalType.Width = 64
			t.InternalType.Oid = oid.T_int8
		case visibleBIT, visibleNONE:
			// Pre-2.1 BIT was using IntFamily with arbitrary widths. Clamp them
			// to fixed/known widths. See #34161.
			switch t.Width() {
			case 16:
				t.InternalType.Oid = oid.T_int2
			case 32:
				t.InternalType.Oid = oid.T_int4
			default:
				// Assume INT8 if width is 0 or not valid.
				t.InternalType.Oid = oid.T_int8
				t.InternalType.Width = 64
			}
		default:
			return errors.AssertionFailedf("unexpected visible type: %d", t.InternalType.VisibleType)
		}

	case FloatFamily:
		// Map visible REAL type to 32-bit width.
		switch t.InternalType.VisibleType {
		case visibleREAL:
			t.InternalType.Oid = oid.T_float4
			t.InternalType.Width = 32
		case visibleDOUBLE:
			t.InternalType.Oid = oid.T_float8
			t.InternalType.Width = 64
		case visibleNONE:
			switch t.Width() {
			case 32:
				t.InternalType.Oid = oid.T_float4
			case 64:
				t.InternalType.Oid = oid.T_float8
			default:
				// Pre-2.1 (before Width) there were 3 cases:
				// - VisibleType = DOUBLE PRECISION, Width = 0 -> now clearly FLOAT8
				// - VisibleType = NONE, Width = 0 -> now clearly FLOAT8
				// - VisibleType = NONE, Precision > 0 -> we need to derive the width.
				if t.Precision() >= 1 && t.Precision() <= 24 {
					t.InternalType.Oid = oid.T_float4
					t.InternalType.Width = 32
				} else {
					t.InternalType.Oid = oid.T_float8
					t.InternalType.Width = 64
				}