From: | Csaba Nagy <ncslists(at)googlemail(dot)com> |
---|---|
To: | Greg Stark <gsstark(at)mit(dot)edu> |
Cc: | Gokulakannan Somasundaram <gokul007(at)gmail(dot)com>, Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, pgsql-hackers list <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: A thought on Index Organized Tables |
Date: | 2010-02-23 12:00:47 |
Message-ID: | 1266926447.14231.29.camel@pcd12478 |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Hi all,
On Mon, 2010-02-22 at 10:29 +0000, Greg Stark wrote:
> On Mon, Feb 22, 2010 at 8:18 AM, Gokulakannan Somasundaram
> <gokul007(at)gmail(dot)com> wrote:
> > a) IOT has both table and index in one structure. So no duplication of data
> > b) With visibility maps, we have three structures a) Table b) Index c)
> > Visibility map. So the disk footprint of the same data will be higher in
> > postgres ( 2x + size of the visibility map).
>
> These sound like the same point to me. I don't think we're concerned
> with footprint -- only with how much of that footprint actually needs
> to be scanned.
For some data the disk foot-print would be actually important: on our
data bases we have one table which has exactly 2 fields, which are both
part of it's primary key, and there's no other index. The table is
write-only, never updated and rarely deleted from.
The disk footprint of the table is 30%-50% of the total disk space used
by the DB (depending on the other data). This amounts to about 1.5-2TB
if I count it on all of our DBs, and it has to be fast disk too as the
table is heavily used... so disk space does matter for some.
And yes, I put the older entries in some archive partition on slower
disks, but I just halve the problem - the data is growing exponentially,
and about half of it is always in use. I guess our developers are just
ready to get this table out of postgres and up to hadoop...
Cheers,
Csaba.
From | Date | Subject | |
---|---|---|---|
Next Message | Gokulakannan Somasundaram | 2010-02-23 13:47:42 | Re: A thought on Index Organized Tables |
Previous Message | Magnus Hagander | 2010-02-23 11:04:41 | Re: Recent vendor SSL renegotiation patches break PostgreSQL |