Re: To BLOB Or Not To BLOB

G'day.

I do a lot of work with the BASIS textual/multi-media RDBMS package and
run into this question all the time.

There is one pretty basic answer:

If you leave BLOBS lying around in the file system - particularly if
it is a Novell etc file system - people move them and the links get
broken.

Just today I had an example where several thousand links broke because
some dumb Novel administrator moved a directory holding files which
were linked to from a database rather than stored in it. (Not my design
decision)

A database that can hold the BLOBS internally avoids this sort of snafu.

(BASIS also has the advantage that it can automagically index almost
any form of BLOB to the word/phrase/sentence level if it is stored in
the database.)

Cheers,
Stephen Davies
"John Henderson" <jrh(at)is(dot)com(dot)fj> wrote:
> Hi,
> It seems that the issue with large objects is "Why do you want the info in a
> database?"
>
> It seems to me that the point of a database is its ability to order and
> relate data. If you want to retrieve the "large-ish text files" based on
> their content then I think you need to have the files in the database so
> they can be searched. However, if you are going to retrieve the files based
> on something about them that is stored as a separate attribute, such as
> their title, then I think that storing the files as large objects is
> unnecessary.
>
> If you have the option to "[do] as pointers t those files" then I think you
> are not intending to use any of Postgres's features beyond its ability to
> store and retrieve data. Surely the file system itself is 'better' at this
> regardless of how stable Postgres LO's are.
>
> I would sure like to hear someone else's opinion on this because it seems
> that quite a few folks are using large objects and I am often curious about
> why.
>
> John Henderson
>
> >A while ago it was being held that the Postgres large object data type
> >was too new and not sufficiently tested and mature to be used in a
> >production environment. I am about to deploy a little database that
> >involves storing large-ish text files (20-500k) which could be either done
> >as large objects or as pointers to those files that would be then stored
> >as ordinary files in the OS's filesystem. I am undecided as to this
> >question. What are the pros and cons? What is the performance in either
> >case vis-a-vis the other? It is a web app; the interface is done in PHP.
> >Beginning from which version is the large object interface (if at all)
> >to be considered stable and ready for production?
> >
> >cheers frank
> >
> >--
> >frank joerdens
> >
> >joerdens new media
> >heinrich-roller str. 16/17
> >10405 berlin
> >germany
> >
> >e: frank(at)joerdens(dot)de
> >t: +49 30 44055471
> >f: +49 30 44055475
> >h: http://www.joerdens.de
> >
> >pgp public key: http://www.joerdens.de/pgp/frank_joerdens.asc
> >

========================================================================
Stephen Davies Consulting scldad(at)sdc(dot)com(dot)au
Adelaide, South Australia. Voice: 08-8177 1595
Computing & Network solutions. Fax: 08-8177 0133