Oracle DBA – A lifelong learning experience

12C Grid – GENO process causes high CPU usage

Posted by John Hallas on July 11, 2018

This is an interesting bug which has affected a number of our databases  – perhaps because we are not patched to the latest levels in every case.
The MoS note is this one – Patch 20373598: GEN0 TIMEOUT ACTION ALWAYS TRY TO INITIALIZE OCR CONTENT    p20373598_121022_Linux-x86-64
OR
fixed in Bug 22291127  12.1.0.2.160419 (Apr 2016) Database Patch Set Update (DB PSU)
Here is view of top showing how a server looks when it is affected, and a list of servers running 12c grid home below the Apr 2016 PSU patch level.
If the server has loads of cores assigned the overall effect will be small as seen here, CPU shows as 2.8% used
Tasks: 618 total,   3 running, 614 sleeping,   0 stopped,   1 zombie
Cpu(s):  2.8%us,  0.2%sy,  0.0%ni, 96.8%id,  0.2%wa,  0.0%hi,  0.0%si,  0.0%st
Mem:  198475784k total, 80283568k used, 118192216k free,  4491100k buffers
Swap: 41680876k total,        0k used, 41680876k free, 56391976k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
44361 oracle    20   0 4225m 2.8g  18m R 99.6  1.5 753924:28 asm_gen0_+ASM
24347 root      20   0  448m 5536 1348 S  4.9  0.0   7480:21 /usr/sbin/collectd -C /etc/collectd.conf -f
68317 oracle    20   0 50.3g 182m 166m S  3.3  0.1   3052:05 ora_pr00_OEMPRD2A
66023 oracle    -2   0 50.3g  19m  17m S  2.3  0.0   1113:44 ora_vktm_OEMPRD2A
34357 oracle    -2   0 1405m  17m  15m S  2.0  0.0  17424:26 asm_vktm_+ASM
67399 oracle    20   0 50.4g  99m  38m S  2.0  0.1   1885:56 oracleOEMPRD2A (LOCAL=NO)

This SQL is a useful way to identify which servers require patching assuming you are using OEM

select
host_name,
home_name,
home_location
patch_id,
install_timestamp,
description</span>
from sysman."MGMT$SOFTWARE_ONEOFF_PATCHES"
where
host_name not in (
select host_name 
from sysman."MGMT$SOFTWARE_ONEOFF_PATCHES"
where patch_id in ('22291127','20373598'))
and home_location like '%12%grid'
and description like '%Database Patch Set Update%'
order by 1,4
;
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