DAO inner objects cause closed ResultSet error about exposed HOT 2 CLOSED

The problem is that all() function (along with find{}) returns SizedCollection which is wrapper over jdbc ResultSet. On each .next() invocation it returns next row from result set and wraps it with an Entity.
Purpose of this is to allow client to control how much data he wants too fetch overall on all()/find() (something like Kotlin sequences).

As PSQL doesn't support concurrent requests within same connection, first result set (Select * FROM PlannedActivities query) is closing by a driver and you fail with org.postgresql.util.PSQLException: This ResultSet is closed exception.

Workaround is to load everything before .forEach() with simple .toList():

val objs = PlannedActivity.all().toList().forEach { act ->
                activs.append("<b>"+act.id+"</b>: "+
                    act.members.joinToString { memb -> memb.user.psnName + " (@" + memb.user.telegramName + ")" }+
                    " going to " + act.activity.name + " " + act.activity.mode +
                    " at <b>" + formatStartTime(act.start) + "</b>\n")
            }```

from exposed.

It worked! Thank you.

Only additional change I had to make was:

     act.members.toList().joinToString { memb -> memb.user.psnName + " (@" + memb.user.telegramName + ")" }+

because it also uses a collection with sub-queries.

Definitely deserves a line in the docs.

from exposed.