How much to identify pending txn/data during oracle streams latency

Question

Hi ,
I have configured Downstream replication between database. Sometime i am getting latency due to large txn. Latency  is taking more than 6 hrs to drain. How to check below things
     pending transaction?
     How much data's are in pending?
     How long it will take to replicate.
Could you please help on this

Answer 1

Hi, You can try as below:
Source Side
Replication is very quick. You can see the progress as below:
1. Sql> Select capture_message_number from v$streams_capture;
XXXXXX
2. Query the current archived logfiles that the stream is processing;
QL> select name, completion_time from v$archived_log where XXXXXX between FIRST_CHANGE# and NEXT_CHANGE#;
NAME                                               COMPLETION_TIME
/AGNCSYST/arch/1_299.dbf                           28-07-2009 13:26:48
Repeat this query a couple of times to see the progress.
When you will get null value, then Capture process is up to date.
TARGET/ Stage side
Then check on Stage side to see the progress
1. Run below SQL -- APPLIED_MESSAGE_NUMBER should moving
column APPLIED_MESSAGE_NUMBER heading "applied_scn" format 999999999999
column OLDEST_MESSAGE_NUMBER heading "oldest_scn" format 999999999999
select APPLY_NAME, APPLIED_MESSAGE_NUMBER, OLDEST_MESSAGE_NUMBER
from dba_apply_progress;
2. Check how far apply process
select (APPLY_TIME-APPLIED_MESSAGE_CREATE_TIME)*86400 "Latency_in_Seconds",
(sysdate-APPLY_TIME)*86400 "Latency_in_Seconds",
TO_CHAR(APPLIED_MESSAGE_CREATE_TIME,'HH24:MI:SS MM/DD/YY')  "Event_Creation",
TO_CHAR(APPLY_TIME,'HH24:MI:SS MM/DD/YY')  "Apply_Time"
FROM DBA_APPLY_PROGRESS;
Latency_in_Seconds Latency_in_Seconds Event_Creation    Apply_Time
              1915                617 11:00:04 08/18/11 11:31:59 08/18/11
Compare the value of Event_creation and Apply time.
Thanks
M