There xmltype is not correctly encoded to xmlChar due possible invalid encoding info in header. It is possible when XML was loaded with recv function and has not UTF8 encoding.
The functions based on xml_parse function works well.
diff --git a/src/backend/utils/adt/xml.c b/src/backend/utils/adt/xml.c
index f81cf489d2..89aae48cb3 100644
--- a/src/backend/utils/adt/xml.c
+++ b/src/backend/utils/adt/xml.c
@@ -3874,9 +3874,11 @@ xpath_internal(text *xpath_expr_text, xmltype *data, ArrayType *namespaces,
ns_count = 0;
}
- datastr = VARDATA(data);
- len = VARSIZE(data) - VARHDRSZ;
+ datastr = xml_out_internal(data, 0);
+ len = strlen(datastr);
+
xpath_len = VARSIZE(xpath_expr_text) - VARHDRSZ;
+
if (xpath_len == 0)
ereport(ERROR,
(errcode(ERRCODE_DATA_EXCEPTION),
