Saturday, 13 July 2024

No SRLs available for T-1

 

 No SRLs available for T-1     

   This message in standby database alertlog indicates no standby redo logs using by standby database for syncing with primary.

        There will be some situations where standby redo logs will not be used even standby redo logs created in standby side. This causes the sync will happen using archivelogs implies the lag in apply.


This can be due to below:

1.Primary thread number and standby thread number is different.

Example:  

  select group#,THREAD#,sum(bytes/1024/1024),status from v$log group by group#,THREAD#,status;


    GROUP#    THREAD# SUM(BYTES/1024/1024) STATUS

---------- ---------- -------------------- ----------------

         9          1                16384 INACTIVE

        10          1                16384 INACTIVE

         8          1                16384 INACTIVE

        12                        16384 CURRENT


select a.group#,b.THREAD#, b.bytes/1024/1024/1024, b.status FROM v$logfile a, v$standby_log b WHERE a.group# = b.group#;


    GROUP#    THREAD# B.BYTES/1024/1024/1024 STATUS

---------- ---------- ---------------------- ----------

        20          0                     16 UNASSIGNED

        21          0                     16 UNASSIGNED

        22          0                     16 UNASSIGNED

        23          0                     16 UNASSIGNED

        24          0                     16 UNASSIGNED


you can see primary thread 1 and standby thread 0. Drop the standby redologs in standby side and recreate with correct thread number matching with primary.

2. Standby redo logs might not be available in physical level, you can check in location whether the standby redo logs available in location or not.

    

3.Standby redo logs size is less than the primary redo logs size.

Primary:

select group#,THREAD#,sum(bytes/1024/1024),status from v$log group by group#,THREAD#,status;


    GROUP#    THREAD# SUM(BYTES/1024/1024) STATUS

---------- ---------- -------------------- ----------------

         9          1                16384 INACTIVE

        10          1                16384 INACTIVE

         8          1                16384 INACTIVE

        12          1                16384 CURRENT



Standby:

select a.group#,b.THREAD#, a.member, b.bytes/1024/1024/1024, b.status FROM v$logfile a, v$standby_log b WHERE a.group# = b.group#;


    GROUP#    THREAD# MEMBER                                                       B.BYTES/1024/1024/1024 STATUS

---------- ---------- ------------------------------------------------------------ ---------------------- ----------

         4          1 +RECO/PSTRPRD_XS6_AMS/ONLINELOG/group_4.259.1160134445                            1 UNASSIGNED

         5          1 +RECO/PSTRPRD_XS6_AMS/ONLINELOG/group_5.260.1160134447                            1 UNASSIGNED

         6          1 +RECO/PSTRPRD_XS6_AMS/ONLINELOG/group_6.261.1160134451                            1 UNASSIGNED

         7          1 +RECO/PSTRPRD_XS6_AMS/ONLINELOG/group_7.262.1160134455                            1 UNASSIGNED


    In primary redo size is 16G but in standby redo logs in standby side is 1G, you can create new standby redologs with correct size and drop old standby redo.

reference: https://support.oracle.com/epmos/faces/DocumentDisplay?_afrLoop=34273136522105&id=2747195.1&_afrWindowMode=0&_adf.ctrl-state=1cxt9fg1sq_151



4. Miss configuration of DEST_1 parameter.

 No need to specify db_unique_name and valid_for for local archiving, you can use below command.

 Alter system set log_archive_dest_1='LOCATION=USE_DB_RECOVERY_FILE_DEST'; 

reference: https://support.oracle.com/epmos/faces/DocumentDisplay?_afrLoop=33554000415773&id=2864452.1&_afrWindowMode=0&_adf.ctrl-state=1cxt9fg1sq_102





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