| From: | Michael Paquier <michael(dot)paquier(at)gmail(dot)com> |
|---|---|
| To: | Subhankar Chattopadhyay <subho(dot)atg(at)gmail(dot)com> |
| Cc: | Postgres General <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: Lag in asynchronous replication |
| Date: | 2017-03-24 04:03:53 |
| Message-ID: | CAB7nPqRMQafurhVh=KUu2fqQm=TdUGdh8REaw08jhr-qCnKU_Q@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
On Thu, Mar 23, 2017 at 11:37 PM, Subhankar Chattopadhyay
<subho(dot)atg(at)gmail(dot)com> wrote:
> in case of automated failover i want to check if slave is lagging from
> master and only if it is in sync, i want to do failover. But I am working in
> a virtual cloud environment so by that time the master VM may not be
> available to me. How can i check the lag in that case ?
Is your environment switching dynamically to async if the lag is too
important? If not, once you have reached a sync state, the master
would wait for all transactions commits to complete on the slave, so
once the client has received a commit confirmation you have the
guarantee that the data is already flushed on the slave. In this case
you don't need to know what happens on the master.
--
Michael
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Subhankar Chattopadhyay | 2017-03-24 06:11:51 | Re: Lag in asynchronous replication |
| Previous Message | Toby Corkindale | 2017-03-24 03:03:15 | Re: pg_last_xact_replay_timestamp() sometimes reports unlikely, very large delays |