Re: Standbys using commas in application_name cannot become sync nodes

Michael Paquier <michael(dot)paquier(at)gmail(dot)com> writes:
> Commas are authorized characters in application_name for a node in
> recovery, however this overlaps with the fact that
> synchronous_standby_names uses commas as a separator for each node
> name. So, if a standby node uses a comma in its name, even if its name
> is set in s_s_names it can never become a synchronous node because
> SplitIdentifierString() splits this parameter with only a comma.

> Even if I have never seen an standby using a comma in its
> application_name, this is a bug, and here are a couple of things that
> we could do regarding it:
> 1) Do not care, who is actually going to use a comma in application_name?!
> 2) Forbid the use of commas in application_name
> 3) Enhaunce a bit s_s_names splitting so as it can consider
> backslash+comma as part of a standby name. In short by setting
> s_s_names = 'foo\,bar', a standby with name 'foo,bar' would be a sync
> node.
> 4) Document the limitation and discourage the use of commas in application_name

(3) seems like a mess with likely side-effects on other uses of
SplitIdentifierString. I'd vote for (2) or (4).

regards, tom lane