Re: Re: new set of psql patches for loading (saving) datafrom (to) text, binary files - Mailing list pgsql-hackers

From Stephen Frost
Subject Re: Re: new set of psql patches for loading (saving) datafrom (to) text, binary files
Date
Msg-id 20170406010759.GP9812@tamriel.snowman.net
Whole thread Raw
In response to Re: Re: new set of psql patches for loading (saving) datafrom (to) text, binary files  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
Andres,

* Andres Freund (andres@anarazel.de) wrote:
> I don't like the API here much.  Loading requires knowledge of some
> magic $1 value and allows only a single column, printing doesn't mean
> much when there's multiple columns / rows.

> I think the loading side of things should be redesigned into a more
> general facility for providing query parameters.  E.g. something like
> \setparam $1 'whateva'
> \setparamfromfile $2 'somefile'
> \setparamfromprogram $3 cat /frakbar
>
> which then would get used in the next query sent to the server.  That'd
> allow importing multiple columns, and it'd be useful for other purposes
> than just loading binary data.

I tend to agree that the loading side should probably be thought through
more.

> I don't yet have a good idea how to deal with moving individual cells
> into files, so they can be loaded.  One approach would be to to have
> something like
>
> \storequeryresult filename_template.%row.%column
>
> which'd then print the current query buffer into the relevant file after
> doing replacement on %row and %column.

I don't actually agree that there's a problem having the output from a
query stored direclty in binary form into a single file.  The above
approach seems to imply that every binary result must go into an
independent file, and perhaps that would be useful in some cases, but I
don't see it as required.

> I don't think we can find an API we agree upon in the next 48h...

Now that there's more than one opinion being voiced on the API, I tend
to agree with this.  Hopefully we can keep the discussion moving
forward, however, as I do see value in this capability in general.

Thanks!

Stephen

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