From: | Denis Perchine <dyp(at)perchine(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Philip Crotwell <crotwell(at)seis(dot)sc(dot)edu> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: overhead of "small" large objects |
Date: | 2000-12-11 05:01:37 |
Message-ID: | 0012111101370E.18833@dyp.perchine.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
> > Is there significant overhead involoved in using large objects that
> > aren't very large?
>
> Yes, since each large object is a separate table in 7.0.* and before.
> The allocation unit for table space is 8K, so your 10K objects chew up
> 16K of table space. What's worse, each LO table has a btree index, and
> the minimum size of a btree index is 16K --- so your objects take 32K
> apiece.
>
> That accounts for a factor of 3. I'm not sure where the other 8K went.
> Each LO table will require entries in pg_class, pg_attribute, pg_type,
> and pg_index, plus the indexes on those tables, but that doesn't seem
> like it'd amount to anything close to 8K per LO.
>
> 7.1 avoids this problem by keeping all LOs in one big table.
Or you can use my patch for the same functionality in 7.0.x.
You can get it at: http://www.perchine.com/dyp/pg/
--
Sincerely Yours,
Denis Perchine
----------------------------------
E-Mail: dyp(at)perchine(dot)com
HomePage: http://www.perchine.com/dyp/
FidoNet: 2:5000/120.5
----------------------------------
From | Date | Subject | |
---|---|---|---|
Next Message | Matthew | 2000-12-11 06:54:28 | RE: Re: Re: Why PostgreSQL is not that popular as MySQL ? |
Previous Message | Roderick A. Anderson | 2000-12-11 04:52:22 | Re: Article involving Postgresql |