Extract Abends With ERROR OGG00868 The number of Oracle redo threads (3) is not the same as the number of checkpoint threads (4). (Doc ID 2301772.1)

Extract Abends With ERROR OGG-00868 The number of Oracle redo threads (3) is not the same as the number of checkpoint threads (4). (Doc ID 2301772.1)

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In this Document

Symptoms

Cause

Solution

References

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APPLIES TO:

Oracle GoldenGate - Version 12.1.2.1.10 and later
Information in this document applies to any platform.

SYMPTOMS

Extract abends with below error:

2017-08-24 18:54:47 ERROR OGG-00868 The number of Oracle redo threads (3) is not the same as the number of checkpoint threads (4). EXTRACT groups on RAC systems should be created with t
he THREADS parameter (e.g., ADD EXT , TRANLOG, THREADS 3, BEGIN...).

2017-08-24 18:54:47 ERROR OGG-01668 PROCESS ABENDING.

CAUSE

Active threads is only 3.

SQL> select distinct(thread#) from v$log;

  THREAD#
----------
  1
  2
  3

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

GGSCI (test1) 3> info LFLXPAR2 showch

EXTRACT LFLXPAR2 Last Started 2017-08-23 21:02 Status ABENDED
Checkpoint Lag 00:00:00 (updated 06:36:25 ago)
Log Read Checkpoint Oracle Redo Logs
  2017-08-24 18:12:37 Thread 1, Seqno 23386, RBA 471552
  SCN 2.2622520145 (11212454737)
Log Read Checkpoint Oracle Redo Logs
  2017-08-24 18:12:36 Thread 2, Seqno 23690, RBA 2405376
  SCN 2.2622520124 (11212454716)
Log Read Checkpoint Oracle Redo Logs
  2017-07-19 23:26:50 Thread 4, Seqno 21084, RBA 1082880
  SCN 2.2598882523 (11188817115)
Log Read Checkpoint Oracle Redo Logs
  2017-08-24 18:12:38 Thread 3, Seqno 23018, RBA 468592776
  SCN 2.2622520149 (11212454741)


Read Checkpoint #1
  Oracle Threaded Redo Log
  Startup Checkpoint (starting position in the data source):
Thread #: 1

Read Checkpoint #2
  Oracle Threaded Redo Log
  Startup Checkpoint (starting position in the data source):
Thread #: 2


Read Checkpoint #3
  Oracle Threaded Redo Log
  Startup Checkpoint (starting position in the data source):
Thread #: 4


Read Checkpoint #4
  Oracle Threaded Redo Log
  Startup Checkpoint (starting position in the data source):
Thread #: 3

SOLUTION

Active threads is only 3.

SQL> select distinct(thread#) from v$log;

  THREAD#
----------
  1
  2
  3

SQL> select distinct(thread#) from gv$thread ;

  THREAD#
----------
  1
  2
  3

Solution 1
=========
1. Deleted the Extract process
2. Re-added the extract process with 3 threads
3. Alter the extract process with the lowest SCN
4. started the extract
5. Alter the pump process with the new sequence number
6. check for the repilcat process lag
7. Alter the replicat process with the new sequence number

Example
=======

1. DELETE EXTRACT LFLXPAR2
2. ADD EXTRACT LFLXPAR2, TRANLOG, BEGIN NOW, THREADS 3
3. ADD EXTTRAIL , EXTRACT LFLXPAR2, SEQNO
4. ALTER EXTRACT LFLXPAR2, SCN 11212454716
5. INFO EXTRACT LFLXPAR2,detail
6. START EXTRACT LFLXPAR2, ATCSN 11212454716

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

If distinct thread shows 4 and thread 4 is not active then,

SQL> select distinct thread# from V$LOG;

  THREAD#
----------
  1
  2
  4
  3

NOTE : In this case , Goldengate Read Checkpoint #3 is mapped to database Thread #: 4

Goldengate Read Checkpoint #1 is mapped to database Thread #: 1

Goldengate Read Checkpoint #2 is mapped to database Thread #: 2

Goldengate Read Checkpoint #3 is mapped to database Thread #: 4  --------------------> We need to ignore this database thread 4

Goldengate Read Checkpoint #4 is mapped to database Thread #: 3

Read Checkpoint #3

Oracle Threaded Redo Log
Startup Checkpoint (starting position in the data source):
Thread #: 4

Solution 2

=========

Please add the below parameter in the extract parameter file and restart the extract process

THREADOPTIONS PROCESSTHREADS EXCEPT 3

or

THREADOPTIONS PROCESSTHREADS SELECT 1
THREADOPTIONS PROCESSTHREADS SELECT 2
THREADOPTIONS PROCESSTHREADS SELECT 4

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

Please Note :  If the Goldengate Read Checkpoint is mapped to the respective database threads. 

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

Goldengate Read Checkpoint #1 is mapped to database Thread #: 1

Goldengate Read Checkpoint #2 is mapped to database Thread #: 2

Goldengate Read Checkpoint #3 is mapped to database Thread #: 3 

Goldengate Read Checkpoint #4 is mapped to database Thread #: 4   --------------------> We need to ignore this database thread 4

 Solution 3
=========

Please add the below parameter in the extract parameter file and restart the extract process

THREADOPTIONS PROCESSTHREADS EXCEPT 4

or

THREADOPTIONS PROCESSTHREADS SELECT 1
THREADOPTIONS PROCESSTHREADS SELECT 2
THREADOPTIONS PROCESSTHREADS SELECT 3

REFERENCES

NOTE:1204284.1 - OGG Activity Logging Tracing
NOTE:2004661.1 - Extract on ADG: OGG-00868 The number of Oracle redo threads (2) is not the same as the number of checkpoint threads (1).
NOTE:166650.1 - Working Effectively With Oracle Support - Best Practices