How to read in more than 250,000 characters XML CLOB field from Oracle into R or SAS?

I need to read in this XML COLB column from Oracle table. I tried the simple read in like below:

xmlbefore <- dbGetQuery(conn, "select ID, XML_TXT from XML_table")  

But I can only read in about 225,000 characters. When I compare with the sample XML file, it only read in maybe 2/3 or 3/4 of the entire field.

I assume R has limitation of maybe 225,000 characters and SAS has even less, like about only 1000 Characters.

How can I read in the entire field with all characters (I think it is about 250,000-270,000)?