Re: pg_waldump stucks with options --follow or -f and --stats or -z

On 2021-Nov-17, Bharath Rupireddy wrote:

> On Wed, Nov 17, 2021 at 7:49 AM Michael Paquier  wrote:
> >
> > At the same time, we could also just let things as they are.  --follow
> > and --stats being specified together is what the user looked for, so
> > they get what they wanted.
> 
> I think the existing way of pg_waldump getting stuck with the
> combination of options  "-s/-f/-z" and "-s/-e/-f/-z" doesn't look good
> for an end user.

I agree that it's not right, but I don't think the solution is to ban
the combination.  I think what we should do is change the behavior to
make the combination potentially useful, so that it waits until program
termination and print the summary then.  Consider "strace -c" as a
precedent: it will also "become stuck" until you kill it, and then it'll
print a nice table, just like the pg_waldump -z gives you.

I think I would even have had occasion to use this as a feature in the
past ...

-- 
Álvaro Herrera           39°49'30"S 73°17'W  —  https://www.EnterpriseDB.com/