OraFAQ Forum: Server Administration » Out of Memory - Runaway Memory, not releasing ORA-04036: PGA memory used by the instance exceeds

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Out of Memory - Runaway Memory, not releasing ORA-04036: PGA memory used by the instance exceeds [message #678257]

Wed, 20 November 2019 17:46

oraclefan12345
Messages: 1
Registered: November 2019

Junior Member

We set PGA_AGGREGATE_LIMIT to 2 up to 6 when running data warehouse extraction on 2 databases(Peoplesoft); however, we still went over the limit and used up all swap space. This crashed both databases on server, pretty bad. We received ORA-04036: PGA memory used by the instance exceeds.
We open a ticket with Oracle and they had us set the limit to 0 but still max out on memory and crashed server and DBS.

I am thinking this must bugs on release 2.

Oracle mentioned that max_map_count should be at least 200000 but our is 65530.

Anyone ran into runaway memory issues? It could be either Oracle bugs, or server configuration.

Interesting same processes ran fine on 12c R1 on the same server so it must be something on Release 2.

From Oracle Support.

1) check current map count value.
eg: more /proc/sys/vm/max_map_count

2) if its lower than 200000, raise it:

vm.max_map_count - should at least be 200000 .

sysctl -w vm.max_map_count=200000

Our server has 65530. Should we increase to at least 200000?

clbdev790::/tmp $ more /proc/sys/vm/max_map_count
65530

From google

From the Linux kernel documentation: max_map_count: This file contains the maximum number of memory map areas a process may have. Memory map areas are used as a side-effect of calling malloc, directly by mmap and mprotect, and also when loading shared libraries.Nov 11, 2017

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Re: Out of Memory - Runaway Memory, not releasing ORA-04036: PGA memory used by the instance exceeds [message #678258 is a reply to message #678257]

Wed, 20 November 2019 20:41

BlackSwan
Messages: 26766
Registered: January 2009
Location: SoCal

Senior Member

Welcome to this forum

Please read and follow the forum guidelines, to enable us to help you:
OraFAQ Forum Guide
How to use {code} tags and make your code easier to read

https://docs.oracle.com/database/121/ADMIN/memory.htm#ADMIN11233

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Re: Out of Memory - Runaway Memory, not releasing ORA-04036: PGA memory used by the instance exceeds [message #678260 is a reply to message #678257]

Thu, 21 November 2019 02:18

John Watson
Messages: 8974
Registered: January 2010
Location: Global Village

Senior Member

Why would you not do as you have been advised: adjust max_map_count ?

Apart from that, I would consider tuning the code in this "extraction" process so that it needs less PGA.

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Re: Out of Memory - Runaway Memory, not releasing ORA-04036: PGA memory used by the instance exceeds [message #678805 is a reply to message #678260]

Wed, 15 January 2020 01:22

aladanh
Messages: 1
Registered: January 2020

Junior Member

I really wanted to send a small word to say thanks to you for the fantastic points you are writing on this site.

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