The step where the product (Source Control for Oracle) accesses the Oracle instance to return a list of schemas is taking a long time to run, and in one of my development instances, it actually fails to finish.

It seems to be running the following SQL

(SELECT username, 'TRUE' as isempty from allusers
minus
select owner, 'TRUE' as isempty from allobjects)
union all
( SELECT username, 'FALSE' as isempty from allusers
intersect
select owner, 'FALSE' as isempty from allobjects)

if the query accepts parameter(s), it should speed up that part tremendously.

(SELECT username, 'TRUE' as isempty from allusers where username = <parameter>
minus
select owner, 'TRUE' as isempty from allobjects where owner = <parameter>)
union all
( SELECT username, 'FALSE' as isempty from allusers where username = <parameter>
intersect
select owner, 'FALSE' as isempty from allobjects where owner = <parameter>)