code: protected synchronized int convertArrayToBaseOid(int oid) {
      Integer i = pgArrayToPgType.get(oid);
      if (i == null) {
        return oid;
      }
      return i;
    }
docs: Return the oid of the array's base element if it's an array, if not return the provided oid.
  This doesn't do any database lookups, so it's only useful for the originally provided type
  mappings. This is fine for it's intended uses where we only have intimate knowledge of types
  that are already known to the driver.
  
  @param oid input oid
  @return oid of the array's base element or the provided oid (if not array)