| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Greg Stark <gsstark(at)mit(dot)edu> |
| Cc: | Simon Riggs <simon(at)2ndquadrant(dot)com>, Josh Berkus <josh(at)agliodbs(dot)com>, Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Keepalive for max_standby_delay |
| Date: | 2010-06-03 15:34:43 |
| Message-ID: | 26977.1275579283@sss.pgh.pa.us |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
Greg Stark <gsstark(at)mit(dot)edu> writes:
>> Well, if the slave can't keep up, that's a separate problem. It will
>> not fail to keep up as a result of the transmission mechanism.
> No, I mean if the slave is paused due to a conflict. Does it stop
> reading data from the master or does it buffer it up on disk? If it
> stops reading it from the master then the effect is the same as if the
> slave stopped "requesting" data even if there's no actual request.
The data keeps coming in and getting dumped into the slave's pg_xlog.
walsender/walreceiver are not at all tied to the slave's application
of WAL. In principle we could have the code around max_standby_delay
notice just how far behind it's gotten and adjust the delay tolerance
based on that; but I think designing a feedback loop for that is 9.1
material.
regards, tom lane
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Greg Stark | 2010-06-03 15:43:54 | Re: Keepalive for max_standby_delay |
| Previous Message | Bruce Momjian | 2010-06-03 15:34:04 | Re: functional call named notation clashes with SQL feature |