Oracle Database 12c – Immediate Kill Session

Recently we have deployed a new Oracle database 12c for our portal application. One of our developer complained that one of his portal schema session is getting terminated continuously. When we Investigate the alert log file then same error has been reported and the sessions are getting terminated.

Error Message in DB alert logfile:

PGA memory used by the instance exceeds PGA_AGGREGATE_LIMIT of 2048 MB
Immediate Kill Session#: 353, Serial#: 36171
Immediate Kill Session: sess: 43d90da20 OS pid: 18855

It will generate the trace file for session that has been killed. We can find  out the user info and the running SQL from the trace file.

Cause:

By default Oracle is configuring  PGA_AGGREGATE_LIMIT parameter to 2GB and any user process which is exceeding the utilization of PGA_AGGREGATE_TARGET parameter with the specified value then the session are being killed by oracle Instannce automatically.

Existing value of  “PGA_AGGREGATE_LIMIT” parameter:

SQL> show parameter pga_aggregate_limit

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
pga_aggregate_limit big integer 2G
SQL>

Solution:

Modify the value of parameter “pga_aggregate_limit” to zero. After setting this parameter all session are  working normal.

Modify the “pga_aggregate_limit”:

SQL> alter system set pga_aggregate_limit=0 scope=both;

System altered.

SQL> show parameter pga_aggregate_limit

NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
pga_aggregate_limit big integer 0
SQL>

Hope this helps. Thanks for reading

regards,

X A H E E R