Re: Keepalive for max_standby_delay - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Keepalive for max_standby_delay
Date
Msg-id 4BF301BD.6060102@enterprisedb.com
Whole thread Raw
In response to Re: Keepalive for max_standby_delay  (Jim Nasby <decibel@decibel.org>)
Responses Re: Keepalive for max_standby_delay
List pgsql-hackers
On 17/05/10 12:36, Jim Nasby wrote:
> On May 15, 2010, at 12:05 PM, Heikki Linnakangas wrote:
>> What exactly is the user trying to monitor? If it's "how far behind is
>> the standby", the difference between pg_current_xlog_insert_location()
>> in the master and pg_last_xlog_replay_location() in the standby seems
>> more robust and well-defined to me. It's a measure of XLOG location (ie.
>> bytes) instead of time, but time is a complicated concept.
>
> I can tell you that end users *will* want a time-based indication of how far behind we are. DBAs will understand
"we'rethis many transactions behind", but managers and end users won't. Unless it's unreasonable to provide that info,
weshould do so.
 

No doubt about that, the problem is that it's hard to provide a reliable 
time-based indication.

--   Heikki Linnakangas  EnterpriseDB   http://www.enterprisedb.com


pgsql-hackers by date:

Previous
From: Jesper Krogh
Date:
Subject: Re: pg_upgrade - link mode and transaction-wraparound data loss
Next
From: Alex Hunsaker
Date:
Subject: Re: BYTEA / DBD::Pg change in 9.0 beta