@madhu I don’t at this point but will ping the guys and get back to you with more into.
Given that your DB’s CPU usage is consistently above 99%, that could be the root cause of all kinds of weird issues. How many historyShards do you have? And how many temporal history service instances do you have? Is it possible to scale up your DB to have more CPU available?
Not an expert on RDS. Have you tried to debug the cpu issue? Troubleshoot high CPU usage on Amazon RDS for MySQL
as i said, this is not happening normally, if i have my cluster as standalone, the cpu usage is hardly 8%
if i configure replication using dns:/// cpu goes 99%,
if i configure replication using ip directly the replication happens and cpu usage is back to 8 or 9%
i have no reason to belive it is RDS issue.
I see the replication table clogged only when i have my replications configured using dns:///
and the same set of configurations where working just fine with 1.14.x…
When using dns:///, the replication stops. Is my understanding correct?
Sorry for delayed reply, i was on vacxation 
Yes with dns:/// the clusters are not able to resolve each other and replication stops.
I tried without dns:/// that too did not help, using ip address i am able to replicate.
dns:/// was working in 1.4.x
things started working after i cleaned up cluster metadata and cluster metadata info table, and also after promoting my namespace to global namespace again