How to resolve ORA-00490 error?
Posted by Pavan DBA on October 17, 2011
Yesterday in one post (https://pavandba.com/2011/10/16/which-process-starts-first-when-instance-is-started/) I explained about PSP0 process which is introduced in 10g
Sometimes all of a sudden our Instance will be crashed and when looked at alert log file we found below error message
ORA-00490: PSP process terminated with error
While PSP process itself terminated due to any error the whole instance is crashed with ORA-00490 error message.
On further check you may found one more error also in the alert log file which describes as
ORA-27300: OS system dependent operation:fork failed with status: 12
ORA-27301: OS failure message: Not enough space
ORA-27302: failure occurred at: skgpspawn3
When operating system is encountering with some unknown error like insufficient space in temp Area or swap Area or insufficient system resources then Oracle throws above errors
Same time PMON is terminating instance with following error with process id of PMON process. Because Oracle processes are being unmanageable of Oracle database instance.
PMON: terminating instance due to error 490
Instance terminated by PMON, pid = 20094
Root Cause:
This error will occur when there is no free space available in swap area of System for spawning new process of Oracle. Due to this reason Process SPwaner process PSP0 (with ORA-00490 error code of Oracle) terminated because it doesn’t able to manage or create Oracle processes. Result is Oracle instance crashed by PMON process with errorstack 490 (which is pointing out ORA-00490). If lack of system resource found then also same situation can be occurring.
Solution :
There are 2 solutions for this problem which are mentioned below
1. Check your swap space and increase swap area in system. Because due to lack of space in swap are Oracle unable to create new process and PSP0 Process SPwaner is unable to manage Oracle process.
2. Check “ulimit” setting for Oracle. “ulimit” is for user shell limitation. If maximum shell limit is reached then also PSP0 process becomes unstable to manage other Oracle processes.Increase the “ulimit” setting for Oracle user.
Note : Hope this helps and Please share this post to your friends in case you feel its informative………..
Pavan DBA's Blog 
prabhu said
i think that PMON is responsible for connection and is started first is it correct.
prabhu said
hi sir,
you that that PSP is the process which is started first among all the process but in alert log i have seen PMON is started first and after that PSP is started.I think for establishing connection PMON is started first.plz give me the reason.
Pavan Kumar said
Hi Prabhu, May be in alert log you will see PMON shows up first, but actually when look at OS resource allocation, it is PSP which will start first……..
PMON is required for establishing a connection. But that connection establishment will happen only after opening database. Don’t consider PMON for SYSDBA connection as SYSDBA can connect even when database is in mount phase.
Please let me know if you got the things?
Pavan Kumar said
Hi Prabhu, as you said PMON is responsible for connection, but it is required only after database open.
prabhu said
thanks sir
Pavan Kumar said
welcome Prabhu…..
suman said
hi sir,
you said that PSP is the background process which is started first of all among the background process but in alert log file i found that PMON is started first and after then PSP is started
Pavan Kumar said
Hi Suman, May be in alert log you will see PMON shows up first, but actually when look at OS resource allocation, it is PSP which will start first……..
suman said
thanks for the info sir
Pavan Kumar said
you are welcome