| From: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
|---|---|
| To: | Simon Riggs <simon(at)2ndQuadrant(dot)com> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Aidan Van Dyk <aidan(at)highrise(dot)ca>, Alvaro Herrera <alvherre(at)commandprompt(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Block-level CRC checks |
| Date: | 2009-12-01 08:04:07 |
| Message-ID: | 4B14CDF7.7030508@enterprisedb.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
Simon Riggs wrote:
> There is no "creation" of corruption events. This scheme detects
> corruption events that *have* occurred. Now I understand that we
> previously would have recovered seamlessly from such events, but they
> were corruption events nonetheless and I think they need to be reported.
> (For why, see Conclusion #2, below).
No, you're still missing the point. The point is *not* random bit errors
affecting hint bits, but the torn page problem. Today, a torn page is a
completely valid and expected behavior from the OS and storage
subsystem. We handle it with full_page_writes, and by relying on the
fact that it's OK for a hint bit set to get lost. With your scheme, a
torn page would become a corrupt page.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Marko Kreen | 2009-12-01 08:13:58 | Re: Application name patch - v4 |
| Previous Message | Simon Riggs | 2009-12-01 07:52:46 | Re: Block-level CRC checks |