I wrote:
> While I've not yet done any excavation in the commit logs to confirm
> this, the nearby comments in the code indicate that separation of COPY
> data from SQL commands was adopted in archive format version 1.3, which
> is ancient. In fact, it's so ancient that there was never a production
> release of pg_dump that created pre-1.3 archives --- only 7.1devel
> versions ever produced those.
I've now poked around in the commit history, and found that pg_dump's
archive format, as well as pg_restore itself, were introduced in commit
500b62b05 of 2000-07-04. The 1.3 format revision was added in commit
e8f69be05 of 2000-07-21. So not only did the prior formats not get
written by any production releases, there was only an interval of a
couple of weeks where they'd even have been emitted by development HEAD.
regards, tom lane