Streams Replication Heartbeat

Streams Replication Heartbeat
Heartbeat table in a Streams replication is very useful, to track the status of the replication. Instead of going to all monitoring tables, it can give us a status at a glance.
We can use following example to implement Streams Heartbeat. Streams replication should already be configured to implement this code.
I've used SCOTT schema to create this table.
------ source site ------
create table heartbeat_monitor(source varchar2(10),last_update timestamp default systimestamp)/
1. SOURCE column, will store the details of the global_name of the site.2. LAST_UPDATE column, will store the last activity time.
To replicate the data, we'll need a JOB to insert the required details.
scott@sourcedb> variable jobno number;
scott@sourcedb>begindbms_job.submit(:jobno, 'insert into scott.heartbeat_monitor (source) select global_name from global_name;', sysdate, 'sysdate+60/(60*60*24)');commit;end;/
Secondly, I've created another job to delete entries older than 2 days, from the heartbeat_monitor table, so that heartbeat_monitor table does not become a problem
scott@sourcedb>variable jobno number;begindbms_job.submit(:jobno, 'delete from scott.heartbeat_monitor where last_update < sysdate -2 and source = (select global_name from global_name);', sysdate, 'sysdate+60/(60)');commit;end;/
If we have 2-way replication configured, then we'll also need similar jobs on target site
------ target site ------
scott@targetdb> variable jobno number;
scott@targetdb>begindbms_job.submit(:jobno, 'insert into scott.heartbeat_monitor (source) select global_name from global_name;', sysdate, 'sysdate+60/(60*60*24)');commit;end;/
scott@targetdb> variable jobno number;
scott@targetdb>begindbms_job.submit(:jobno, 'delete from scott.heartbeat_monitor where last_update < sysdate -2 and source = (select global_name from global_name);', sysdate, 'sysdate+60/(60)');commit;end;/
Now to track the heartbeat, we can use following script
select source, to_char(systimestamp,'dd-mon-yyyy hh24:mi:ss.ff5') as "current time",to_char(max(last_update),'dd-mon-yyyy hh24:mi:ss.ff5') as "last heartbeat received"from scott.heartbeat_monitorwhere source <> (select global_name from global_name) group by source/