I could see below error in logs in our cloud environment. ERROR org.h

How can I reduce the packet size?

Is this error coming from a queryrule()? If so try using a!queryentity() and only return the columns that are necessary for your use case as this can help to reduce packet size. You can also using pagingInfo if your query returns multiple results.
forum.appian.com/.../System_Functions.html

Also take a look at dev.mysql.com/.../packet-too-large.html

Thanks but the problem is how to know where exactly the issue is happening. By Looking at the below error how can anybody tell where exactly the issue is happening?

00:00:12,211 INFO [stdout] (ElementEventQueue.QProcessor-1) 2015-02-03 00:00:12,211 [ElementEventQueue.QProcessor-1] ERROR org.hibernate.util.JDBCExceptionReporter - Packet for query is too large (4197887 > 4194304). You can change this value on the server by setting the max_allowed_packet' variable.

we have asked to change the max_allowed_packet to 20MB. But we are not able to make out if issue is in our custom plugin or our code.