I'm in process of revisiting bug #137 in view of COPY protocol, and
hitting a few issues worthy of asking things a bit broadly...

I'm adding a new table to capture DDL, as per the discussions with Jan/Steve.

Now, the _normal_ schema for this would be something like:

create table @NAMESPACE at .sl_ddl (
	ddl_origin			int4,
	ddl_txid			bigint,
	ddl_actionseq		int8,
	ddl_query			text
) WITHOUT OIDS;

Alas, there are parts of the log queries that use "log_txid" and
"log_actionseq" to generate chunks of queries that I'd really like to
use, and not regenerate from scratch.

To readily do that, I need to rename 2 of the columns to conform with
the names on sl_log_1/sl_log_2, thus:

create table @NAMESPACE at .sl_ddl (
	ddl_origin			int4,
	log_txid			bigint,
	log_actionseq		int8,
	ddl_query			text
) WITHOUT OIDS;

Is this a horrible inconsistency that I ought to rectify?  Or shall we
not lose too much sleep over this?