RAC 10.2.0.4, event gc cr block busy & log file switch

Question

hello everybody,
i would like to know if there is any dependencies between gc cr block busy and log switch in the one node of the rac cluster.
i had a select and its completion time lasted 12 secs instead of 1, the start time of the select is the start time of the log switch on the node.
But when i looked into the active session history the session which was standing for that select had been waiting gc cr block busy instead log file switch completion.
While looking to the Google resources i ve noticed that "The gc current block busy and gc cr block busy wait events indicate that the
remote instance received the block after a remote instance processing delay.
In most cases, this is due to a log flush".
I would be really greatfull if anybody would be able to locate the initial dependancy i ve mantioned and explain the cause of the issue as i can not quite get why the selection took so long.
Thank you in advance!

Answer 1

Did you told "log file switch"?
you mean log file switch (checkpoint incomplete) or log file switch (archiving needed) or log file switch/archive or log file switch (clearing log file) or log file switch completion or log switch/archive
however a instance can wait ... if you find high values about waiting, you may tune your database.
please show us
- Top 5 Wait Events
SQL> alter session set nls_date_format='YYYY/MM/DD HH24:MI:SS';
SQL> select name, completion_time from V$ARCHIVED_LOG order by completion_time ;
Check How often do you switch logfile to archive log? ... Every switch log file... you may find "log file switch" waiting
I see... you no high DML activitiy.
But Please check High segment + object and query on AWR report... (example: Segments by Physical Writes )
just investigate
Good Luck