Re: pg_validatebackup -> pg_verifybackup?

On Fri, Apr 10, 2020 at 5:24 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Meh. I would argue that that's an actively BAD idea. The use-cases
> are entirely different, the implementation is going to be quite a lot
> different, the relevant options are going to be quite a lot different.
> It will not be better for either implementors or users to force those
> into the same executable.

I think Andres has a point, but on balance I am more inclined to agree
with you. It may be that in the future it will make sense to organize
things differently, but I would rather arrange them according to what
makes sense now, and then change it later, even though that makes for
some user-visible churn. The thing is that we don't really know what's
going to happen in future releases, and our track record when we try
to guess is very poor. Creating stuff that we hope will get extended
to do this or that in a future release can end up looking really
half-baked if the code doesn't get extended in the anticipated
direction.

I *would* like to find a way to address the proliferation of binaries,
because I've got other things I'd like to do that would require
creating still more of them, and until we come up with a scalable
solution that makes everybody happy, there's going to be progressively
more complaining every time. One possible solution is to adopt the
'git' approach and decide we're going to have one 'pg' command (or
whatever we call it). I think the way that 'git' does it is that all
of the real binaries are stored in a directory that users are not
expected to have in their path, and the 'git' wrapper just looks for
one based on the name of the subcommand. So, if you say 'git thunk',
it goes and searches the private bin directory for an executable
called 'git-thunk'. We could easily do this for nearly everything 'pg'
related, so:

clusterdb -> pg clusterdb
pg_ctl -> pg ctl
pg_resetwal -> pg resetwal
etc.

I think we'd want psql to still be separate, but I'm not sure we'd
need any other exceptions. In a lot of cases it won't lead to any more
typing because the current command is pg_whatever and with this
approach you'd just type a space instead of an underscore. The
"legacy" cases that don't start with "pg" would get a bit longer, but
I wouldn't lose a lot of sleep over that myself.

There are other possibilities too. We could try to pick out individual
groups of commands to merge, rather than having a unified framework
for everything. For instance, we could turn
{cluster,create,drop,reindex,vacuum}db into one utility,
{create,drop}user into another, pg_dump{,all} into a third, and so on.
But this seems like it would require making a lot more awkward policy
decisions, so I don't think it's a great plan.

Still, we need to agree on something. It won't do to tell people that
we're not going to commit patches to add more functionality to
PostgreSQL because it would involve adding more binaries. Any
particular piece of functionality may draw substantive objections, and
that's fine, but we shouldn't stifle development categorically because
we can't agree on how to clean up the namespace pollution.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company