| From: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
|---|---|
| To: | "Bossart, Nathan" <bossartn(at)amazon(dot)com> |
| Cc: | Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>, "andres(at)anarazel(dot)de" <andres(at)anarazel(dot)de>, "masao(dot)fujii(at)oss(dot)nttdata(dot)com" <masao(dot)fujii(at)oss(dot)nttdata(dot)com>, "pgsql-hackers(at)lists(dot)postgresql(dot)org" <pgsql-hackers(at)lists(dot)postgresql(dot)org>, "mengjuan(dot)cmj(at)alibaba-inc(dot)com" <mengjuan(dot)cmj(at)alibaba-inc(dot)com>, "Jakub(dot)Wartak(at)tomtom(dot)com" <Jakub(dot)Wartak(at)tomtom(dot)com> |
| Subject: | Re: prevent immature WAL streaming |
| Date: | 2021-09-17 20:31:34 |
| Message-ID: | 202109172031.67v345vxyano@alvherre.pgsql |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On 2021-Sep-17, Bossart, Nathan wrote:
> I gave the patch a read-through. I'm wondering if the
> XLOG_OVERWRITE_CONTRECORD records are actually necessary. IIUC we
> will set XLP_FIRST_IS_ABORTED_PARTIAL on the next page, and
> xlp_pageaddr on that page will already be validated in
> XLogReaderValidatePageHeader(). Does adding this new record also help
> ensure the page header is filled in and flushed to disk?
That was the first implementation, a few versions of the patch ago. An
added benefit of a separate WAL record is that you can carry additional
data for validation, such as -- as suggested by Andres -- the CRC of the
partial data contained in the message that we're skipping. I didn't
implement that, but it should be trivial to add it.
--
Álvaro Herrera 39°49'30"S 73°17'W — https://www.EnterpriseDB.com/
"How strange it is to find the words "Perl" and "saner" in such close
proximity, with no apparent sense of irony. I doubt that Larry himself
could have managed it." (ncm, http://lwn.net/Articles/174769/)
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Fabrízio de Royes Mello | 2021-09-17 20:32:32 | Re: Minimal logical decoding on standbys |
| Previous Message | Tom Lane | 2021-09-17 20:09:16 | Re: initdb --pwfile /dev/zero |