user process exceeds maxssiz, maxdsiz and maxtsiz

[Morten Kristiansen]

Hi,

Today we had a problem that a process had allocated 3 GB memory. When I checked the maxsize for processes they are set to:
maxdsiz_64bit = 2 GB
maxssiz_64bit = 1 GB
maxtsiz_64bit = 1 GB

The process was a shellscript that called sqlplus against an oracle database, which started an oracle procedure collecting data in a lob variabel sending it to a java utility which wrote data to a file.

I guess it should be kernel variable maxssiz which should restrict the amount of allocated memory. How can the process allocate more than the kernel variables are set?

We are running in a HP-UX 11.11 64-bit environment.

Thanks in advance
Morten

[Steven E. Protter]

Shalom Morten,

HP-UX devides its memory areas into various pools. Probably the total memory allocated to the process is 3 GB but it does not exceed any of the above limitations.

Hopefully your system is patched reasonably to prevent patching being a factor.

Learning links:
http://docs.hp.com/en/B2355-60105/maxssiz.5.html
http://www.google.com/url?sa=t&ct=res&cd=1&url=http%3A%2F%2Fdocs.hp.com%2Fen%2F939%2FKCParms%2FKCparam.MaxSsiz.html&ei=K7WORKrRMbKCQsPUuIcN&sig2=aZEZY2TIF_BSyh95w5OpYA

http://www.google.com/url?sa=t&ct=res&cd=4&url=http%3A%2F%2Fdocs.hp.com%2Fen%2FJ4258-90024%2Fch01s02.html&ei=YrWORMmgHZKmQe6duOwM&sig2=6LT8Fqs4pi74XmwH1UXYNw
http://www.google.com/url?sa=t&ct=res&cd=6&url=http%3A%2F%2Fdocs.hp.com%2Fen%2FJ4258-90027%2Fch02s01.html&ei=YrWORMmgHZKmQe6duOwM&sig2=j5m60txH0MhgcG1CGAZn0g

SEP

[Ninad_1]

Hi,

If you have reached th limit configured in the kernel then there is no way to exceed that limit at user level. You need to increase the kernel parameters to have the increased limits.
It should be the maxdsiz_64bit and not the maxssiz_64 bit. maxdsiz is for the data segment required by the process, whereas maxssiz is for stack - and if stack requirement is quite high (1GB is far more than enough for 1 process) then probably the programming needs to be revisited as it is not a sign of good programming if huge stack is required.
Note : you will require a reboot after kernel recompilation

Regards,
Ninad

[Michael Steele_2]

This is a tremendous amount of memory and adding more should not be so automatic during root cause analysis. ( The answer to every programming problem is not more memory. ) More then likely you've got some unfreed memory allocation (malloc?) and it needs to be cleaned up. Can you also Paste these results into an attachment mon ami?

# vmstat 5 5
# sar -u 5 5
# sar -v 5 5
# sar -b 5 5
# sar -d 5 5
# swapinfo -tam