Re: Assertion failure with summarize_wal enabled during pg_createsubscriber

I went ahead and committed 0001, which is pretty trivial. Hopefully,
at least, it's trivial enough that I didn't mess it up.

Here's a rebase of 0002 and 0003, now 0001 and 0002, with one minor
fix to hopefully avoid annoying CI.

I'm still hoping for some review/feedback/testing of these before I
commit them, but I also don't want to wait too long.

Thanks,

-- 
Robert Haas
EDB: http://www.enterprisedb.com