Wait for the event log to wait for the event solution.

Wait for the event log to wait for the event solution.

I insisted on reading three sets of RAC AWR every day and summarized it.

Query the SQL statement of the log wait event:

9i: select * from v $ event_name where name like '% log %'; (about 14)
10g: select name, wait_class from v $ event_name where name like '% log %'; (about 35)
11g: select name, wait_class from v $ event_name where name like '% log %'; (about 30)

The following are the most common examples:

1. Log file switch (archiving needed)

That is, when the log is switched to the target log group, archiving is not yet completed. You must wait.

Possible cause: redo, archive partition I/O performance is poor, archive writing is slow, and the number of log groups is set unreasonably

Solution: 1. Increase the size of the log group or log group member.

2. Adjust archive logs to disks with high IO performance, such as storage

3. Adjust the log_archive_max_processes parameter.

Ii. Log file switch (checkpoint incomplete)

Indicates that the dirty data protected by the log group has not been written to the target log group during log switching.

Possible cause: DBWn writing is too slow, and I/O problems exist.

Solution: 1. add an additional DBWn

2. Increase the size of the log group or log group member

Iii. Log File Sync

Possible causes: LGWR write efficiency is low, and commit is too frequent.

Solution: 1. Improve LGWR write efficiency and use disks with good IO Performance

2. Batch submission (real-time online business operations with caution)

3. Use the nologging/unreoverable option ()

Iv. log file single write

Cause: the waiting time when the log file header is updated

V. log file parallel write

Cause: Waiting for multiple log group members to be written in parallel

Vi. log buffer space

Cause: logs generated by the database are faster than logs written by LGWR, or log switching is too slow.

Solution: 1. Increase log buffer

2. Disk I/O bottlenecks

Note: The DB plan is a redo partition, and the hard disk occupied by the arch partition space should be RAID 1 as much as possible.

To be continued

 

Wait log

The original life was really calm, and I had the same experience. I was very happy every day, but since I met her again, she was my original classmate, it turned out that I had a crush on her but didn't develop any further, but I met her again. The first sight I gave was not the joy of a good friend's reunion, but the feeling of love at first sight. I really felt that I fell in love with her, I have never been so persistent. I must say to myself that this girl is the person I will take care of in the future, but she does not belong to me now. I told her that she knows what I mean, she said that she also liked me, but now is not the time. At last, I chose to wait. I hope that I can wait for another piece of my intoxicated love. I often ask myself, if I met her again, it was a chance or a punishment from God. Who can give me some advice ???
Don't wait for a person again, just wait for a river to flow, and ask for it to return to the starting point, unless it is time back. Everyone knows how changes work. We cannot be the stupid person who knows what it is.
Maybe you will say that he is really good. He is worth it. So what about you. You should believe that you are really good, so you cannot spend time waiting for someone. If someone else loves you, you will also fall in love with others.

A waiting and waiting log

Dear. I will wait. Keep waiting!
No matter what happens.
Regardless of the final result.
You need to know. Someone is waiting for you in the original place.
I will keep watching our memories and wait for you to continue.
I love you. Always. Forever. This life. The afterlife!