Maximum number of process exceeded in DAC

Some times in BI Apps, you can find that the DAC execution plan getting aborted when more number of tasks are being executed in parallel. And you can find that by merely restarting the execution plan manually the execution plan continues.

This could be because of any of the below two items

1) Maximum connection between DAC and Informatica exceeded

2) Maximum number of processes or session in DB exceeded

For the first one 1) Maximum connection between DAC and Informatica exceeded, one could go to the Informatica tab and increase the maximum connections.

For the second one 2) Maximum number of processes or session in DB exceeded,  perform the below steps.

1. Login as sysdba sqlplus / as sysdba

2. Check Current Setting of Parameters

sql> show parameter sessions

sql> show parameter processes

sql> show parameter transactions
3. If you are planning to increase “sessions” parameter you should also plan to increase “processes and “transactions” parameters. A basic formula for determining  these parameter values is as follows:   processes=x   sessions=x*1.1+5   transactions=sessions*1.1

4. These paramters can’t be modified in memory. You have to modify the spfile only (scope=spfile) and bounce the instance.

sql> alter system set processes=500 scope=spfile;

sql> alter system set sessions=555 scope=spfile;

sql> alter system set transactions=610 scope=spfile;

sql> shutdown abort

sql> startup

After this, the DAC works without need for any manual intervention.