Optimizer Choosing Nested-Loop Joins Instead of Hash-Joins

In one of my databases, one application query suddenly started to pick Nested-Loop joins instead of Hash-Joins and took almost 6 hours to complete which gets completed in less than 10 secs with Hash-Joins. The same query in another similar database with same configuration and same data is doing fine and using hash joins. There is…

SRVCTL fails to start RAC resources:CRS-0215

After upgrading RAC database to 10204 and applying CRS bundle patch-1 for 10204 crs home, srvctl command fails to startup resources on rac nodes. While starting up RAC resources using SRVCTL following error occurs in CRSD.log file: $ srvctl start instance -d rac -i rac2 2009-04-09 13:45:22.091: [ CRSRES][2611477408][ALERT]0`ora…inst` on member “ has experienced an…

Connections to DataBase Hang Including “/ as sysdba”

Recently I faced one issue where all the connection to database hung and it was also not possible to login to database using “/ as sysdba”. To get access of sqlplus I used the following syntax: $ sqlplus -prelim / as sysdba With “prelim” option we can run some commands which will help in collection…

Creating Oracle Extended RAC on Oracle VM

Yesterday, I found one very useful article at OTN “Creating Oracle Extended RAC” on completely virtual environment using Oracle VM. As Virtualization is becoming popular day by day and is very cost effective, one must know how to use this to simulate actual environments. Click  here for details on Oracle Extended RAC on Oracle VM.