[PATCH][DOC] Fix for PREPARE TRANSACTION doc and postgres_fdw message.

Hi,

As per the following code, t1 is a remote table through postgres_fdw:

test=# BEGIN;
BEGIN
test=# SELECT * FROM t1;
...

test=# PREPARE TRANSACTION 'gxid1';
ERROR:  cannot prepare a transaction that modified remote tables

I have attached a patch to the documentation that adds remote tables to
the list of objects where any operation prevent using a prepared
transaction, currently it is just notified "operations involving
temporary tables or the session's temporary namespace".

The second patch modify the message returned by postgres_fdw as per the
SELECT statement above the message should be more comprehensible with:

    ERROR:  cannot PREPARE a transaction that has operated on remote tables

like for temporary objects:

    ERROR:  cannot PREPARE a transaction that has operated on temporary
objects

Best regards,

--

Gilles

--
Gilles Darold
http://www.darold.net/