The Watch a Tag widget may start to return empty results due to a bug with Oracle 12c, where certain types of database query joins return inconsistent results.

• When configuring the Watch a Tag widget you may see that when you configure the widget for certain tags then you will get zero or empty results.
• There is no way to predict what tags may work or not work and you may see that some tags that previously returned results will suddenly fail to return any results.
• If a full outer join view was joined on fixed-length character columns (e.g. CHAR or NCHAR) that is defined with different length, then the join may produce the wrong result.

Environment

This issue is only observed on Jive On-Premise that is connected to an Oracle 12c database.

Note: This does not impact Jive customers that are on Jive's Hosted or Cloud environments.

Reproduction Steps

Sample Database query to help identify if your Oracle 12c database is impacted by this bug:

CREATE table small(s_id number, s_char nchar(2) not null);
CREATE table large(l_id number, l_char nchar(10) not null);
CREATE table dummy(col1 number, col2   nchar(10) not null);
begin
  for i in 1..2 loop
    INSERT into small values(i,i);
    INSERT into large values(i,i);
    INSERT into dummy values(i,i);
    COMMIT;
  end loop;
end;
/
SELECT * from small s
full outer join
   dummy on col1=1
  inner join
  (
   SELECT l_char
     from large
   WHERE l_id=2
  ) l
  on s.s_char=l.l_char
;

Result: No rows are returned when there should be 1 row.

Root Cause

• A known bug with Oracle 12c databases can result in Jive's Watch a Tag widget returning empty or unexpected results.
• Oracle has identified the bug with ID 21814415 and has provided a workaround for the problem.

Note: This issue is caused by an Oracle bug and Jive is unable to resolve or workaround the issue.