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

From: Pavel Stehule <pavel(dot)stehule(at)gmail(dot)com>
To: Stephen Frost <sfrost(at)snowman(dot)net>
Cc: "Jason O'Donnell" <odonnelljp01(at)gmail(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: new set of psql patches for loading (saving) data from (to) text, binary files
Date: 2017-03-18 16:51:48
Message-ID: CAFj8pRCdRazO0-3y02_ZdCQp7eMV_Lem7R1bgvWHjujt=7amPg@mail.gmail.com
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Hi

> > > There's a whitespace-only hunk that shouldn't be included.
> > >
> > > I don't agree with the single-column/single-row restriction on these.
> I
> > > can certainly see a case where someone might want to, say, dump out a
> > > bunch of binary integers into a file for later processing.
> > >
> > > The tab-completion for 'gstore' wasn't correct (you didn't include the
> > > double-backslash). The patch also has conflicts against current master
> > > now.
> > >
> > > I guess my thinking about moving this forward would be to simplify it
> to
> > > just '\gb' which will pull the data from the server side in binary
> > > format and dump it out to the filename or command given. If there's a
> > > new patch with those changes, I'll try to find time to look at it.
> >
> > ok I'll prepare patch
>
> Great, thanks!
>

I rewrote these patches - it allows binary export/import from psql and the
code is very simple. The size of the patch is bigger due including 4KB
binary file (in hex format 8KB).

What is done:

create table foo foo(a bytea);

-- import
insert into foo values($1)
\gloadfrom ~/xxx.jpg bytea

-- export
\pset format binary
select a from foo
\g ~/xxx2.jpg

tested on import 55MB binary file

Comments, notes?

Available import formats are limited to text, bytea, xml - these formats
are safe for receiving data via recv function.

Regards

Pavel

>
> Stephen
>

Attachment Content-Type Size
psql-binary-export-import.patch text/x-patch 25.5 KB

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