In case Master Node is down and Clone is set up in cfg file.
We can notice few of the Read only Query to Keystore goes to Clone server even after
Master Node is up.
In v188.8.131.52 we introduced a “blacklist” that servers are placed on when we get an error
from them. The default time they are on the blacklist is 5 minutes, after which we will try
them again. There is no command to reset the black list.
Any commands that require creating a new key, such as create database, are sent to the
Master key manager regardless of whether it is on the blacklist (so in affect the blacklist
is only for read requests).
If we have trouble reaching all servers (primary and clones), we reset the blacklist and
So with blacklist If Master is down it will be added to Blacklist. And read-only request
will go to Clone.As Master will be on Blacklist even if it comes up in next 5 minutes all
read-only request will go to Clone,as Master will remain in the Blacklist.
After 5 minutes if Master is available it will be removed from Blacklist and will continue
serving all request.
UNAVAILABLE_SERVER_BLACKOUT_PERIOD is variable control time for blacklist 5 minutes is default time.
Optional. The amount of time, in seconds, to skip sending key requests to a particular
master or clone centralized key manager after a failed connection attempt or it has
returned errors. This parameter was introduced in Db2 V184.108.40.206. Default value: 300 seconds.