Richard Yen <dba at richyen.com> writes:
> I'm wondering if there's any difference between lag_events and
> lag_time in the sl_status table/view.  There are often times where I
> notice that the lag_events is 0, yet the lag_time is somewhere in the
> range of 20-30 seconds.  Why is this the case?

That will typically happen if there are no updates getting submitted
to the origin node.

If the origin is not being updated, then it may take 30 seconds to
generate a SYNC (depending on configuration!).  In that case,
subscribers may sit at the same SYNC number as the origin for that 30
seconds.

After 30s, one of the timeouts is reached, a SYNC (that involves no
updates!) is generated, and so it takes very little time for the
subscribers to process that SYNC, and then sit, lagging by nothing,
for another 30s.

If the application is quiescent, then that's a to-be-expected
behaviour.
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