Reader Server:

• IDLE - Performing no work
   

• DEQUEUE MESSAGES - Dequeuing events from the queue
   

• SCHEDULE MESSAGES – Working out the dependencies between events and assembling events into transactions

The following SQL block shows some useful Apply reader details for a given specific Apply process that helps with monitoring.

COL FROM_STREAMS_APPLY_READER format a60

select
 'Session SID           : ' || SID || chr(10) ||
 'APPLY Name            : ' || APPLY_NAME|| chr(10) ||
 'Current State         : ' || STATE || chr(10) ||
 'TOT MSGs Dequed       : ' || TOTAL_MESSAGES_DEQUEUED || chr(10) ||
 'Time last msg received: ' || to_char(DEQUEUE_TIME,
                               'YYYY-MM-DD HH24:MI') || chr(10) ||
 'Last DeQued MSG  NUM  : ' || DEQUEUED_MESSAGE_NUMBER || chr(10) ||
 'CRT-Time at SRCDB of Last MSG : ' ||
                         to_char(DEQUEUED_MESSAGE_CREATE_TIME,
                        'YYYY-MM-DD HH24:MI')  || chr(10) || 
 'SGA Used so far       : ' || SGA_USED || chr(10) ||
 'Last browse SCN       : ' || LAST_BROWSE_NUM || chr(10) ||
 'Oldest SCN            : ' || OLDEST_SCN_NUM
FROM_STREAMS_APPLY_READER
from V$STREAMS_APPLY_READER
/