| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Hannu Krosing <hannu(at)skype(dot)net> |
| Cc: | Marko Kreen <markokr(at)gmail(dot)com>, Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Is full_page_writes=off safe in conjunction with |
| Date: | 2006-04-16 20:24:57 |
| Message-ID: | 18532.1145219097@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
Hannu Krosing <hannu(at)skype(dot)net> writes:
> But if we do need to consider the kernel-level behaviour mentioned, then
> the whole PITR thing becomes an impossibility. Consider the case when we
> get a torn page during the initial copy with tar/cpio/rsync/whatever,
> and no WAL record updates it.
The only way the backup program could read a torn page is if the
database is writing that page concurrently, in which case there must
be a WAL record for the action.
This was all thought through carefully when the PITR mechanism was
designed, and it is solid -- as long as we are doing full-page writes.
Unfortunately, certain people forced that feature into 8.1 without
adequate review of the system's assumptions ...
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Martijn van Oosterhout | 2006-04-16 20:29:11 | Re: Regrading TODO item alerting pg_hba.conf from SQL |
| Previous Message | Hannu Krosing | 2006-04-16 19:46:46 | Re: Is full_page_writes=off safe in conjunction with |