XID Data Types

Hello everyone,

Take the query below:

select *,xmin from settings where xmin > '187167023'::xid limit 5;

Although the docs say this is a 32 bit datatype, I have casted the 
integer '187167023' also to an xid type, but it seems that there is no 
operator to do a comparison, since I get this error:

didit=# select *,xmin from settings where xmin > '187167023'::xid limit 5;
ERROR:  operator does not exist: xid > xid

Any pointers or suggestions?

- Ericson