Re: [HACKERS] Measuring replay lag

On Thu, Dec 29, 2016 at 1:28 AM, Thomas Munro
<thomas.munro@enterprisedb.com> wrote:
> On Thu, Dec 22, 2016 at 10:14 AM, Thomas Munro
> <thomas.munro@enterprisedb.com> wrote:
>> On Thu, Dec 22, 2016 at 2:14 AM, Fujii Masao <masao.fujii@gmail.com> wrote:
>>> I agree that the capability to measure the remote_apply lag is very useful.
>>> Also I want to measure the remote_write and remote_flush lags, for example,
>>> in order to diagnose the cause of replication lag.
>>
>> Good idea.  I will think about how to make that work.
>
> Here is an experimental version that reports the write, flush and
> apply lag separately as requested.  This is done with three separate
> (lsn, timestamp) buffers on the standby side.  The GUC is now called
> replication_lag_sample_interval.  Not tested much yet.

Here is a new version that is slightly refactored and fixes a problem
with stale samples after periods of idleness.

-- 
Thomas Munro
http://www.enterprisedb.com

-- 
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers