| From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
|---|---|
| To: | Bruce Momjian <bruce(at)momjian(dot)us> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: Finding slave WAL application time delay |
| Date: | 2010-07-21 00:36:47 |
| Message-ID: | AANLkTi=KsgRCNzr98Ek8FjXjvGz9y9Us4URk40GCXsgz@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Tue, Jul 20, 2010 at 3:13 PM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> Someone at OSCON just asked if there is a way to find the _time_ delay
> between received and applied WAL. Right now
> pg_last_xlog_replay_location() only reports the information in WAL
> scale. It would be nice to report that in time, e.g. milliseconds.
There's probably more than one way you can define this. See, for
example, previous discussions of max_standby_delay.
> Because an idle master will not generate WAL, I don't think there is a
> way to report the time delay in receiving WAL.
You could certainly come up with a sensible definition for this,
though there are also nonsensical ones.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise Postgres Company
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