Re: Re: new set of psql patches for loading (saving) data from (to) text, binary files

Greetings,

* Pavel Stehule (pavel(dot)stehule(at)gmail(dot)com) wrote:
> 2017-04-06 3:34 GMT+02:00 Stephen Frost <sfrost(at)snowman(dot)net>:
> > Having the template not require the row/column place-holders included
> > strikes me as more likely to be confusing. My initial thinking around
> > this was that users who actually want independent files would simply
> > issue independent queries, while users who want to take a bunch of int4
> > columns and dump them into a single binary file would be able to do so
> > easily.
> >
> > I'm not against adding the ability for a single query result to be saved
> > into independent files, but it strikes me as feature creep on this basic
> > capability. Further, I don't see any particular reason why splitting up
> > the output from a query into multiple files is only relevant for binary
> > data.
>
> The files can be simply joined together outside psql

Just as multiple queries could be done to have the results put into
independent files.

> Personally I prefer relation type: single field, single file in special g
> command - because I can simply off all formatting and result should be
> correct every time.

Not sure why you think there would be a formatting issue or why the
result might not be 'correct'.

> Stephen, have you some use case for your request?

The initial patch forced a single value result. Including such a
restriction doesn't seem necessary to me. As for use-case, I've
certainly written code to work with binary-result data from PG
previously and it seems entirely reasonable that someone might wish to
pull data into a file with psql and then process it. I've been
wondering if we should consider how binary-mode COPY works, but that
format ends up being pretty inefficient due to the repeated 32-bit
length value for every field.

My initial reaction was primairly that I didn't see value in the
somewhat arbitrary restriction being imposed on usage of this.

Thanks!

Stephen