Re: PATCH: psql tab completion for SELECT

Edmund Horner <ejrh00(at)gmail(dot)com> writes:
> On 15 January 2018 at 15:45, Andres Freund <andres(at)anarazel(dot)de> wrote:
>> All worries like this are supposed to check the server version.

> In psql there are around 200 such tab completion queries, none of
> which checks the server version. Many would cause the user's
> transaction to abort if invoked on an older server. Identifying the
> appropriate server versions for each one would be quite a bit of work.

> Is there a better way to make this more robust?

Maybe it'd be worth the effort to wrap tab completion queries in
SAVEPOINT/RELEASE SAVEPOINT if we're inside a user transaction
(which we could detect from libpq's state, I believe).

That seems like an independent patch, but it'd be a prerequisite
if you want to issue tab completion queries with version dependencies.

A bigger point here is: do you really want SELECT tab completion
to work only against the latest and greatest server version?
That would become an argument against committing the feature at all;
maybe not enough to tip the scales against it, but still a demerit.

regards, tom lane