sql: fix serialization of pg_index.indkey

`indkey` is an `int2vector`, which is serialized as a space-delimited
string containing the elements of the vector. Sequelize relies on this
representation, splitting `indkey` by spaces. This fixes compatibility
with Sequelize and has been tested with Hibernate, GORM, and SQLAlchemy.

This change adds an INT2VECTOR column type that maps to a new
TypeIntVector/DIntVector that uses DOidWrapper to wrap DArray with the
int2vector OID. The new column type allows the serialization of `indkey`
to match what Postgres emits.

pkg/sql/create.go

@@ -1157,7 +1157,7 @@ func MakeTableDesc(
 		if d, ok := def.(*parser.ColumnTableDef); ok {
 			if !desc.IsVirtualTable() {
 				if _, ok := d.Type.(*parser.ArrayColType); ok {
-					return desc, util.UnimplementedWithIssueErrorf(2115, "ARRAY column types are unsupported")
+					return desc, util.UnimplementedWithIssueErrorf(2115, "ARRAY and INT2VECTOR column types are unsupported")
 				}
 			}
 

pkg/sql/parser/col_types.go

@@ -325,6 +325,12 @@ func arrayOf(colType ColumnType, boundsExprs Exprs) (ColumnType, error) {
 	}
 }
 
+var int2vectorColType = &ArrayColType{
+	Name:        "INT2VECTOR",
+	ParamType:   intColTypeInt,
+	BoundsExprs: Exprs{NewDInt(DInt(-1))},
+}
+
 // Pre-allocated immutable postgres oid column type.
 var oidColTypeOid = &OidColType{}
 
@@ -440,6 +446,9 @@ func CastTargetToDatumType(t CastTargetType) Type {
 	case *CollatedStringColType:
 		return TCollatedString{Locale: ct.Locale}
 	case *ArrayColType:
+		if ct.Name == "INT2VECTOR" {
+			return TypeIntVector
+		}
 		return tArray{CastTargetToDatumType(ct.ParamType)}
 	case *OidColType:
 		return TypeOid

pkg/sql/parser/datum.go

@@ -2005,6 +2005,7 @@ func wrapWithOid(d Datum, oid oid.Oid) Datum {
 		return nil
 	case *DInt:
 	case *DString:
+	case *DArray:
 	case dNull, *DOidWrapper:
 		panic(fmt.Errorf("cannot wrap %T with an Oid", v))
 	default:
@@ -2154,3 +2155,9 @@ func mixedTypeCompare(l, r Datum) (int, bool) {
 	}
 	return 1, true
 }
+
+// NewDIntVectorFromDArray is a helper routine to create a *DIntVector
+// (implemented as a *DOidWrapper) initialized from an existing *DArray.
+func NewDIntVectorFromDArray(d *DArray) Datum {
+	return wrapWithOid(d, oid.T_int2vector)
+}