Обсуждение: using Postgres to store many small files

I am currently working on a Java web application in which we are making
use of the JDBC driver for Postgres 7.4.1.  Part of our application
allows the administrators to manage a large number of small images,
most of them not exceeding 5KB.  There is about a gigabyte of these
small files.  We're currently storing the files on disk and the other
information about the file in the database (historical reasons that I
won't complain about here).
   I recently discovered the Hibernate project and was pleasantly
surprised how simple it was to store an image in Postgres as a bytea
using Hibernate's BLOB support.  I'm wondering if Postgres would have
any problem handling all of our files if we were to put them into
Postgres as bytea data.  And how well would Postgres scale as the
number of files increased?
   Our Java application and Postgres are currently running on the same
machine, a dual Xeon 2.6Ghz with 1GB of RAM.  We are currently not
working this machine very hard at all.
   Thanks,
     -M@

On Thursday 04 March 2004 01:03, Matthew Hixson wrote:
[snip]
>    I recently discovered the Hibernate project and was pleasantly
> surprised how simple it was to store an image in Postgres as a bytea
> using Hibernate's BLOB support.  I'm wondering if Postgres would have
> any problem handling all of our files if we were to put them into
> Postgres as bytea data.  And how well would Postgres scale as the
> number of files increased?

PG itself cares nothing whether the data is text or bytea - it won't be able
to compress the data much presumably (if they are GIF/JPEG). The only issue I
can think of is that you will have to access these images through PG rather
than the filesystem - worth checking there aren't any little utilities
relying on that.

>    Our Java application and Postgres are currently running on the same
> machine, a dual Xeon 2.6Ghz with 1GB of RAM.  We are currently not
> working this machine very hard at all.

More RAM might be an idea - it's not expensive. Also - consider whether this
will have an impact on your backup plans.

--
  Richard Huxton
  Archonet Ltd

I am assuming these are mugshots displayed on web pages? Put them in
Postgres by all means, I would, but push them out to the file system as
well so the webserver can return them directly, saving database access CPU
cycles. Intercept 404s with a jsp that checks if it was an image being
asked for. If it was and it can find it in the DB, push it out to the
client and write it to disk for the next time. Or run a nightly script
that checks for missing files.

Bas.