Versions:  ADS v 18.0.17
Postgresql:  9.6

How to reproduce:

Connect to a postgres version 9.6 database.

Right click on the database, select DBA Tools  then Session Manager.  (Nothing happens)

If you open the sql log while opening the session manager, you can see the exception issued by the ADS generated sql.  It looks for a column called waiting which no longer exists in the pg_stat_activity view in PG 9.6.  See here .

SELECT pid, datid, datname, usesysid, usename , query, client_addr, client_port, query_start, backend_start, waiting, xact_start, state FROM pg_catalog.pg_stat_activity

org.postgresql.util.PSQLException: ERROR: column "waiting" does not exist
  Position: 110
    at org.postgresql.core.v3.QueryExecutorImpl.receiveErrorResponse(QueryExecutorImpl.java:2453)
    at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2153)
    at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:286)
    at org.postgresql.jdbc.PgStatement.executeInternal(PgStatement.java:432)
    at org.postgresql.jdbc.PgStatement.execute(PgStatement.java:358)
    at org.postgresql.jdbc.PgStatement.executeWithFlags(PgStatement.java:305)
    at org.postgresql.jdbc.PgStatement.executeCachedSql(PgStatement.java:291)
    at org.postgresql.jdbc.PgStatement.executeWithFlags(PgStatement.java:269)
    at org.postgresql.jdbc.PgStatement.executeQuery(PgStatement.java:236)
 
    at java.lang.Thread.run(Thread.java:748)