Re: doc: Mention clock synchronization recommendation for hot_standby_feedback
Fujii Masao <masao.fujii@oss.nttdata.com>
From: Fujii Masao <masao.fujii@oss.nttdata.com>
To: Jakub Wartak <jakub.wartak@enterprisedb.com>,
Amit Kapila <amit.kapila16@gmail.com>
Cc: PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2025-03-03T09:48:41Z
Lists: pgsql-hackers
On 2025/03/03 16:35, Jakub Wartak wrote: > Hi Amit, > > On Mon, Mar 3, 2025 at 6:26 AM Amit Kapila <amit.kapila16@gmail.com> wrote: > [..] > > OK, sure. > >> How about something like: "Note that if the clock on standby is moved >> ahead or backward, the feedback message may not be sent at the >> required interval. This can lead to prolonged risk of not removing >> dead rows on primary for extended periods as the feedback mechanism is >> based on timestamp." > > Sure thing. I've just added '(..) In the extreme cases this can..' as > it is pretty rare to hit it. Patch attached. When the clock moves forward or backward, couldn't it affect not only the standby but also the primary? I’m wondering because TimestampDifferenceExceeds() seems to be used in several places in addition to hot standby feedback. Regards, -- Fujii Masao Advanced Computing Technology Center Research and Development Headquarters NTT DATA CORPORATION
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doc: Mention clock synchronization recommendation for hot_standby_feedback
- 0fcf02ad4568 18.0 landed