One obvious solution is to handle this at the application level. Read database
to get path to image file, retrieve image file if it exists, and if it doesn't
exist, delete or modify the database record to reflect what you just learned
about reality. If necessary, you could periodically go through every path in the
database to verify their existence on the FS, and delete the path records for
missing files en masse, though I wouldn't do this too often.
Hope this helps,
Wes
Nadim Bitar <nadiizu%earthlink.net@interlock.lexmark.com> on 06/27/2002 06:10:07
AM
To: Karel Zak <zakkr%zf.jcu.cz@interlock.lexmark.com>
cc: pgsql-general%postgresql.org@interlock.lexmark.com (bcc: Wesley
Sheldahl/Lex/Lexmark)
Subject: Re: [GENERAL] Large Objects
The only thing that concerns me about using the filesystem is what
happens if the user deletes an image from the FS, the image table would
be in an inconsistent state. Still trying to think of an elegant
solution to solve that.
On 木, 2002-06-27 at 00:50, Karel Zak wrote:
> On Wed, Jun 26, 2002 at 08:56:11PM -0700, Nadim Bitar wrote:
> >
> >
> > I have a collection of images that I want to store in a database. The
> > collection is currently 12 GB.
>
> Are you sure? Why not use standard FS and to DB store path to files? :-)
>
> > Can anyone give me some advice or links to any documents that discuss
> > the different methods to accomplish this. I already read techdocs
> > documents related to large objects. I just want some advice on good ways
> > to do it.
>
> The current PostgreSQL allows to store large data to standard table
> rows too. You needn't use large-object interface.
>
> > The database is going to be accessed through a Servlet (JDBC).
> > One thing that wasn't clear from techdocs was the disk space usage. If i
> > store 12 GB in the database without deleting it from the filesystem, it
> > is going to occupy another 12 GB. Is this right?
>
> Sure. The database use own and private dataspace and not links to
> some external files.
>
> Karel
>
> --
> Karel Zak <zakkr@zf.jcu.cz>
> http://home.zf.jcu.cz/~zakkr/
>
> C, PostgreSQL, PHP, WWW, http://docs.linux.cz, http://mape.jcu.cz
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