Re: [HACKERS] Re: proposal - psql: possibility to specify sort for describe commands, when size is printed

Hi!

On Mon, Nov 27, 2017 at 10:18 PM, Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
wrote:

> I though about this design more time. I see following disadvantages
>
> 1. we are not able to check all possible variants of extended query. If
> there will be some custom error, then we will raise pretty ugly error
> messages,
>

Yes, that's an inevitable shortcoming. psql is not backend and can't
perform all the required checks on its side...

2. I don't thing so using "Size" as table size in human readable format and
> "size" as table size in raw format is intuitive, but any change of "Size"
> can introduce some (less probability compatibility issues),
>

Oh, this is surprisingly hard problem which probably have only imperative
solution...

3. What queries will contains size calculations? It is not cheap - requires
> AccessShareLock
>

Sorry, I didn't understand this point. Yes, size calculation requires
locking, but that is already true for \dt+ and \l+. Why this is
disadvantage of proposed approach?

------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company