duplicated sequence numbers in V$ARCHIVED_LOG in DataGuard Configuration

[Hewlett]

Hi folks,

I've set up a physical standby for one of our live instances, standby
redo logs are configured on both the primary standby site. I switched
over the databases back and forth a couple of times. the replication
seems to work fine as archive log are shipped to the standby instantly,
DML/DDL statement tests aslo shows replication is working. but when I
query the V$ARCHIVED_LOG, I found a some sequence# are duplicated, the
duplicated sequence numbers can be APPLIED or NOT APPLIED one another,
as shown below:
==============================
on the primary:
--------------------
SQL> SELECT THREAD#, SEQUENCE#, FIRST_CHANGE#, NEXT_CHANGE#,
REGISTRAR, CREATOR, APPLIED FROM V$ARCHIVED_LOG ORDER BY SEQUENCE#;

THREAD# SEQUENCE# FIRST_CHANGE# NEXT_CHANGE# REGISTR CREATOR APP
---------- ---------- ------------- ------------ ------- ------- ---
1 95 5488325885 5488357133 FGRD FGRD NO
1 95 5488325885 5488357133 ARCH ARCH NO
1 96 5488357133 5488357414 FGRD FGRD NO
1 96 5488357133 5488357414 ARCH ARCH NO
1 97 5488357414 5488358664 FGRD FGRD NO
1 97 5488357414 5488358664 ARCH ARCH NO
1 98 5488358664 5488359222 FGRD FGRD NO
1 98 5488358664 5488359222 ARCH ARCH NO
1 99 5488359222 5488359781 FGRD FGRD NO
1 99 5488359222 5488359781 FGRD FGRD YES
1 100 5488359781 5488361387 FGRD FGRD NO
1 100 5488359781 5488361387 FGRD FGRD YES
1 101 5488361387 5488477056 FGRD FGRD NO
1 101 5488361387 5488477056 ARCH ARCH NO
1 102 5488477056 5488477061 FGRD FGRD NO
1 102 5488477056 5488477061 ARCH ARCH YES
1 103 5488477061 5488477708 RFS FGRD YES
1 103 5488477061 5488477708 FGRD FGRD NO
1 104 5488477708 5488478323 RFS FGRD YES
1 105 5488478323 5488478527 RFS FGRD YES
1 106 5488478527 5488478985 RFS FGRD YES
1 107 5488478985 5488479707 FGRD FGRD NO
1 107 5488478985 5488479707 FGRD FGRD YES
1 108 5488479707 5488504894 FGRD FGRD NO
1 108 5488479707 5488504894 FGRD FGRD YES
1 109 5488504894 5488521489 FGRD FGRD NO
1 109 5488504894 5488521489 FGRD FGRD YES
1 110 5488521489 5488522044 FGRD FGRD NO
1 110 5488521489 5488522044 ARCH ARCH NO
1 111 5488522044 5488522743 FGRD FGRD NO
1 111 5488522044 5488522743 FGRD FGRD YES

31 rows selected.

on the standby:
-----------------------

SQL> SELECT THREAD#, SEQUENCE#, FIRST_CHANGE#, NEXT_CHANGE#,
REGISTRAR, CREATOR, APPLIED FROM V$ARCHIVED_LOG ORDER BY SEQUENCE#;

THREAD# SEQUENCE# FIRST_CHANGE# NEXT_CHANGE# REGISTR CREATOR APP
---------- ---------- ------------- ------------ ------- ------- ---
1 95 5488325885 5488357133 RFS ARCH YES
1 96 5488357133 5488357414 RFS ARCH YES
1 97 5488357414 5488358664 RFS ARCH YES
1 98 5488358664 5488359222 RFS ARCH YES
1 99 5488359222 5488359781 RFS FGRD YES
1 100 5488359781 5488361387 RFS FGRD YES
1 101 5488361387 5488477056 RFS ARCH YES
1 102 5488477056 5488477061 RFS ARCH YES
1 103 5488477061 5488477708 RFS FGRD YES
1 104 5488477708 5488478323 FGRD FGRD NO
1 104 5488477708 5488478323 FGRD FGRD NO
1 105 5488478323 5488478527 FGRD FGRD NO
1 105 5488478323 5488478527 FGRD FGRD YES
1 106 5488478527 5488478985 RFS FGRD YES
1 106 5488478527 5488478985 FGRD FGRD NO
1 107 5488478985 5488479707 RFS FGRD YES
1 108 5488479707 5488504894 RFS FGRD YES
1 109 5488504894 5488521489 RFS FGRD YES
1 110 5488521489 5488522044 RFS ARCH YES
1 111 5488522044 5488522743 RFS FGRD YES

20 rows selected.

========================

another phenomina observed is that ARCH for a sequence# 110 stays in
CLOSING status, although the scorreponding archived log has been
received by standby and applied to the database:

on the primary:
----------------------
SQL> SELECT PROCESS, STATUS, THREAD#, SEQUENCE#, BLOCK#, BLOCKS FROM
V$MANAGED_STANDBY;

PROCESS STATUS THREAD# SEQUENCE# BLOCK# BLOCKS
--------- ------------ ---------- ---------- ---------- ----------
ARCH CLOSING 1 110 1 412
ARCH CONNECTED 0 0 0 0

on the standby:
------------------------
SQL> SELECT PROCESS, STATUS, THREAD#, SEQUENCE#, BLOCK#, BLOCKS FROM
V$MANAGED_STANDBY;

PROCESS STATUS THREAD# SEQUENCE# BLOCK# BLOCKS
--------- ------------ ---------- ---------- ---------- ----------
ARCH CONNECTED 0 0 0 0
ARCH CONNECTED 0 0 0 0
MRP0 WAIT_FOR_LOG 1 112 0 0
RFS RECEIVING 1 110 412 412

Could anybody shed a light on the aboved questions?

Thanks in advance,

Hewlett

[fitzj...@cox.net]

Not until you provide the Oracle version, all four numbers. We have no
idea as to the nature of your problem without such information.

David Fitzjarrell

[Hewlett]

David,

The relplication confiuration uses Oracle 9.2.0.7.0 on Redhat Linux
2.4.21-4.EL.

Thanks,

Hewlett