Ensure that vector indexes can only be created on JSON and Vector columns.

Author: nicktobey

sql/errors.go

@@ -923,6 +923,9 @@ var (
 	// ErrFullTextInvalidColumnType is returned when a Full-Text index is declared on a non-text column.
 	ErrFullTextInvalidColumnType = errors.NewKind("all Full-Text columns must be declared on a non-binary text type")
 
+	// ErrVectorInvalidColumnType is returned when a Vector index is declared on a non-vector column.
+	ErrVectorInvalidColumnType = errors.NewKind("a vector index colum must be a vector or JSON")
+
 	// ErrGeneratedColumnValue is returned when a value is provided for a generated column
 	ErrGeneratedColumnValue = errors.NewKind("The value specified for generated column %q in table %q is not allowed.")
 

sql/rowexec/ddl_iters.go

@@ -2008,6 +2008,22 @@ func (b *BaseBuilder) executeAlterIndex(ctx *sql.Context, n *plan.AlterIndex) er
 			return nil
 		}
 
+		if indexDef.IsVector() {
+			// Validate that the type is exactly one column and it's something we can make a vector index of.
+			if len(indexDef.Columns) != 1 {
+				return fmt.Errorf("a vector index must have exactly one column")
+			}
+			indexColNameLower := strings.ToLower(indexDef.Columns[0].Name)
+			for _, tblCol := range idxAltTbl.Schema() {
+				if indexColNameLower == strings.ToLower(tblCol.Name) {
+					if !types.IsVectorConvertable(tblCol.Type) {
+						return sql.ErrVectorInvalidColumnType.New()
+					}
+					break
+				}
+			}
+		}
+
 		err = idxAltTbl.CreateIndex(ctx, indexDef)
 		if err != nil {
 			if sql.ErrDuplicateKey.Is(err) && n.IfNotExists {

sql/types/typecheck.go

@@ -238,3 +238,16 @@ func IsYear(t sql.Type) bool {
 	_, ok := t.(YearType_)
 	return ok
 }
+
+// IsVectorConvertable checks if t can be implicitly converted to a vector of floats.
+func IsVectorConvertable(t sql.Type) bool {
+	if t == nil {
+		return false
+	}
+	switch t.Type() {
+	case sqltypes.TypeJSON, sqltypes.Vector, sqltypes.Binary:
+		return true
+	default:
+		return false
+	}
+}