Re: pg_dump without blobs

From: Sébastien Boutté <sebastien(dot)boutte(at)gmail(dot)com>
To: "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com>
Cc: "Vivek Khera" <vivek(at)khera(dot)org>, "PostgreSQL general" <pgsql-general(at)postgresql(dot)org>
Subject: Re: pg_dump without blobs
Date: 2007-07-16 20:24:14
Message-ID: 60e9579c0707161324h265aabe6h3d79a6baace3c9ec@mail.gmail.com
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I understand that i cannot do a dump of a database without bytea
values.I hope that these feature would be present in next version of
pg_dump as we can store large binary values in these sort of fields
and pg_dump taking a lot of time for dumping the database.
For the moment, I will patch my database to transform my bytea field
into lo (oid) field.
I would to do something similar like this :

update table set new_field = oldfield

but i have problem with cast from bytea to oid.
Is there an efficient way of doing this update ?

Thank you,

Sébastien Boutté

On 7/16/07, Joshua D. Drake <jd(at)commandprompt(dot)com> wrote:
> Vivek Khera wrote:
> >
> > On Jul 16, 2007, at 9:26 AM, Francisco Reyes wrote:
> >
> >> I guess the next question is 'what does postgresql considers a blob'?
> >> bytea fields? How about a large text with megabytes worth of data?
> >
> > bytea and text fields are NOT blobs. they are what you access via the
> > 'large object' functions.
>
> To follow up on this.
>
> In oracle large text CLOB and binary objects BLOB are synonomous (I
> believe) with PostgreSQL TEXT and BYTEA.
>
> PostgreSQL also supports a non standard, and frankly better
> implementation called lo for binary data, which also uses BYTEA data but
> breaks it up to make it more efficient per row.
>
> There is no way to "not" dump your TEXT and BYTEA data from a particular
> column if you are dumping the whole table.
>
> One option would be to use CREATE TEMP TABLE AS SELECT... and then dump
> that temp table.
>
> Joshua D. Drake
>
>
> >
> >
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