Version 4

    Summary

    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.

     

    This issue is only observed in a customer's On-Premise Jive instance that is connected to an Oracle 12c database. This issue does not impact Jive customers that are in Jive's Hosted or Cloud environments.

     

    Please note, this Watch a Tag issue is caused by an Oracle bug and Jive is unable to resolve or workaround the issue.

     

    Issue Symptoms

    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.

     

    Issue Details

    The reason for why the Watch a Tag widget may start to return empty results is because of a bug with Oracle 12c, where certain types of database query joins will return inconsistent results.

     

    If a full outer join view was joined on fixed length character columns (eg. CHAR or NCHAR) that is defined with different length, then the join may produce a wrong result in some cases.

     

    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

    ;

    ^

    no rows are returned when there should be 1 row

     

     

    Issue Workaround

    There are 2 workarounds for this Oracle bug

     

    Workaround

    alter session set "_optimizer_ansi_rearchitecture"= false;

    or

    alter session set "optimizer_features_enable"="11.2.0.4";

     

     

    Next Steps

    For more information on the bug please contact Oracle Support and reference bug ID 21814415.

     

    If you have applied the workaround and are still seeing the issue then please create a new Jive support case.