Re: ORA-04030 possible unix limits??

From: Vishal Gupta <vishal_at_vishalgupta.com>
Date: Sun, 19 Mar 2017 10:45:38 +0000
Message-ID: <30D45395-9F64-4780-B467-9B0E4392F97A_at_vishalgupta.com>



Please check _realfree_heap_pagesize_hint (at instance level) and vm.max_map_count (cat /proc/sys/vm/max_map_count) at OS level.    

Maximum Process level PGA Memory - By default each database process on linux, can take up to 4GB of maximum PGA (Program Global Area) memory. This maximum limit is determined (_realfree_heap_pagesize_hint at instance level * vm.max_map_count at OS level) . Default of both these parameters is 64k, so we get default maximum each process level PGA of 4GB.  

vm.max_map_count – defines the maximum number of VMAs (Virtual Memory Areas) that a particular process can own. VMA is a continuous area of virtual address space. This has a default value of 64k (65536)  

_realfree_heap_pagesize_hint - hint for real-free page size in bytes. This has a default value of 64k (65536)  

Bug 11852492 : ORA-4030 OCCURS WHEN PGA EXCEEDS 4GB. This is not a bug, but more of a default configuration, if one requires more than 4GB of PGA memory then parameter needs to be adjusted.        

Regards,

Vishal Gupta  

From: <oracle-l-bounce_at_freelists.org> on behalf of Henry Poras <henry.poras_at_gmail.com> Reply-To: <henry.poras_at_gmail.com>
Date: Thursday, 16 March 2017 at 17:19
To: ORACLE-L <oracle-l_at_freelists.org> Subject: ORA-04030 possible unix limits??  

I am running on Oracle 12.1.0.2  

We are currently getting 4030 (timobj call) which I have tracked to an aggregate function which is instantiating lots of (untunable) pga memory.  

Our pga_aggregate_target is 700GB and

our pga_aggregate_limit is 900G  

We are not coming close to using our aggregate memory, yet the process is erroring out at 32GB. I am trying to see if this is an Oracle limit (in the past versions, this kind of untunable allocation would continue to rise) or a linux one.  

I have checked both ulimit -a and ulimit -Hm with both being unlimited. Could there be another place that Linux is limiting the process? Has the Oracle PGA allocation changed in 12c?  

Thanks.  

Henry  

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Received on Sun Mar 19 2017 - 11:45:38 CET

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