From: | Simon Riggs <simon(at)2ndquadrant(dot)com> |
---|---|
To: | Heikki Linnakangas <heikki(at)enterprisedb(dot)com> |
Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Jacky Leng <lengjianquan(at)163(dot)com>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Why copy_relation_data only use wal whenWALarchivingis enabled |
Date: | 2007-10-17 17:29:49 |
Message-ID: | 1192642189.4233.129.camel@ebony.site |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers pgsql-patches |
On Wed, 2007-10-17 at 18:13 +0100, Heikki Linnakangas wrote:
> > The test script you
> > showed cheats six-ways-from-Sunday to cause an OID collision that would
> > never happen in practice. The only case where it would really happen
> > is if a table that has existed for a long time (~ 2^32 OID creations)
> > gets dropped and then you're unlucky enough to recycle that exact OID
> > before the next checkpoint --- and then crash before the checkpoint.
>
> Yeah, it's unlikely to happen, but the consequences are horrible.
When is this going to happen?
We'd need to insert 2^32 toast chunks, which is >4 TB of data, or insert
2^32 large objects, or create 2^32 tables, or any combination of the
above all within one checkpoint duration *and* exactly hit the exact
same relation.
That's a weird and huge application, a very fast server and an unlucky
DBA to hit the exact OID to be reused and then have the server crash so
we'll ever notice.
--
Simon Riggs
2ndQuadrant http://www.2ndQuadrant.com
From | Date | Subject | |
---|---|---|---|
Next Message | Heikki Linnakangas | 2007-10-17 17:36:32 | Re: Why copy_relation_data only use walwhenWALarchivingis enabled |
Previous Message | Heikki Linnakangas | 2007-10-17 17:28:11 | Re: Why copy_relation_data only use walwhenWALarchivingis enabled |
From | Date | Subject | |
---|---|---|---|
Next Message | Heikki Linnakangas | 2007-10-17 17:36:32 | Re: Why copy_relation_data only use walwhenWALarchivingis enabled |
Previous Message | Heikki Linnakangas | 2007-10-17 17:28:11 | Re: Why copy_relation_data only use walwhenWALarchivingis enabled |