KJC: Wait for msg sends to complete

To investigate a query performance issues on one of our RAC database with two instances, I have initiated the 'oradebug dump errorstack 3' command for the session which was running the query. However, after few minutes I had canceled the operation as it was taking a long time and surprisingly, I found that the session is waiting for 'KJC: Wait for msg sends to complete' event. Although the event disappeared after few minutes, but it gave me an enough nightmare by that time. I didn't find any useful info about this event, but, I have to take sometime to investigate the behavior.

happy reading,

Jaffar

SELECT FOR UPDATE OF" Hangs in 11.2.0.1

While going through a bug list on metalink I have come across of a ML note: "SELECT FOR UPDATE OF" Hangs in 11.2.0.1 [ID 1081727.1] and thought to blog about it which could be useful for the people who are on 11g or planning to go to 11g. Below is the extract from the note:

Applies to:  Version: 11.2.0.1 - Release: 11.2 applies to any platform. 

Symptoms "SELECT FOR UPDATE OF" Hangs in 11.2.0.1.


SQL:
SELECT table1.rowid
FROM table1 JOIN table2 t2 ON table1.id = t2.id
FOR UPDATE OF table1.text1,table1.text2;

Cause
Bug 9278351 "SELECT FOR UPDATE OF" HANGS IN 11.2.0.1
Base Bug 9294110 LEFT OUTER JOIN WITH FOR UPDATE CLAUSE HANGS FOREVER

The 10046 trace shows high 'cursor: pin S wait on X':
Solution
  Apply Patch 9294110.


happy reading

Jaffar