Oracle : ORA-4030 in AIX Environment

If a session tries to allocate pga memory more than the upper limit specified at OS level, it will error out with:
ORA-04030: out of process memory when trying to allocate 249880 bytes (QERHJ hash-joi,kllcqas:kllsltba)

checking the ulimit settings on AIX:
> ulimit -a
time(seconds) unlimited
file(blocks) unlimited
data(kbytes) 256000
stack(kbytes) unlimited
memory(kbytes) 256000
coredump(blocks) 2097151
nofiles(descriptors) 2000

You can see that the maximum memory which can be allocated in chunk is 250M.

This needs to be set to unlimited.

edit /etc/security/limits file and set it as follows:

oracle:
fsize = -1
core = 2097151
cpu = -1
data = -1
rss = -1
stack = -1
stack_hard = -1
nofiles = 2000

here oracle is an OS user using which oracle database is installed. relogin to OS with this user and issue shall be fixed.