Oracle Background Processes (Including Parallel Processes) Using Only First 8 CPUs (Half) on 16-CPU Server Under NUMA (Doc ID 760705.1)

Last updated on MARCH 27, 2014

Applies to:

Oracle Database - Enterprise Edition - Version 10.2.0.4 and later
Information in this document applies to any platform.

Symptoms



On a 16-CPU server, all Oracle background processes (including parallel slaves) appear to be running on only half of the CPUs.  The data below shows this was not limited to only the _pxx_ processes, but applied to all background processes:

 

DB background processes:
CPU
|
v
2 ? 19151 oracle 241 20 40679M 53204K run 93:22 65.54 65.43 ora_p025_rtfeq101
3 ? 19159 oracle 241 20 40675M 53652K run 94:58 54.64 54.54 ora_p029_rtfeq101
6 ? 19133 oracle 241 20 40679M 57124K run 92:58 41.88 41.81 ora_p016_rtfeq101
4 ? 19498 oracle 148 20 40651M 25572K run 25:04 2.88 2.88 ora_dbw0_rtfeq101
6 ? 19502 oracle 148 20 40651M 17048K run 26:03 2.07 2.07 ora_dbw2_rtfeq101
3 ? 19504 oracle 154 20 40636M 14804K sleep 19:36 0.51 0.51 ora_dbw3_rtfeq101
1 ? 19500 oracle 154 20 40634M 13776K sleep 18:37 0.37 0.37 ora_dbw1_rtfeq101
1 ? 19506 oracle 154 20 40649M 13668K sleep 44:24 0.22 0.22 ora_lgwr_rtfeq101
2 ? 19518 oracle 154 20 40623M 3952K sleep 19:33 0.20 0.20 ora_mmnl_rtfeq101
2 ? 219508 oracle 154 20 40632M 12028K sleep 9:48 0.10 0.10 ora_ckpt_rtfeq101
1 ? 19491 oracle 154 20 40625M 6272K sleep 7:13 0.10 0.10 ora_pmon_rtfeq101
3 ? 19514 oracle 154 20 40681M 63116K sleep 8:38 0.05 0.05 ora_cjq0_rtfeq101
4 ? 6351 oracle 154 20 40623M 3996K sleep 0:07 0.02 0.02 ora_q002_rtfeq101
6 ? 19493 oracle 154 20 40622M 3812K sleep 0:59 0.02 0.02 ora_psp0_rtfeq101
7 ? 19496 oracle 154 20 40622M 4120K sleep 1:13 0.02 0.02 ora_mman_rtfeq101
1 ? 19510 oracle 154 20 40711M 65312K sleep 2:57 0.02 0.02 ora_smon_rtfeq101
3 ? 19512 oracle 154 20 40685M 48160K sleep 0:13 0.02 0.02 ora_reco_rtfeq101
6 ? 19516 oracle 154 20 40683M 59472K sleep 6:03 0.02 0.02 ora_mmon_rtfeq101
3 ? 19521 oracle 154 20 40626M 4860K sleep 0:04 0.02 0.02 ora_d000_rtfeq101
2 ? 19523 oracle 154 20 40625M 4636K sleep 0:07 0.02 0.02 ora_s000_rtfeq101
3 ? 19636 oracle 154 20 40623M 4016K sleep 0:40 0.02 0.02 ora_qmnc_rtfeq101
7 ? 19643 oracle 154 20 40623M 3704K sleep 0:12 0.02 0.02 ora_q000_rtfeq101
. . .

Connections into the database (shadow processes), however, did use more than the first 8 CPUs.

DB shadow processes:  
CPU 


10   ?         735 oracle   154 20 40861M   241M sleep    3:24  0.26  0.26 oraclertfeq101  
13   ?         932 oracle   154 20 40625M  6224K sleep    0:00  0.02  0.02 oraclertfeq101  
 9   ?        2394 oracle   154 20 40627M  7592K sleep    0:02  0.02  0.02 oraclertfeq101  
15   ?        2411 oracle   154 20 40625M  6132K sleep    0:07  0.02  0.02 oraclertfeq101  
 4   ?       10992 oracle   154 20 40629M  5820K sleep    0:00  0.02  0.02 oraclertfeq101

Changes

The 10.2.0.4 patchset was applied.

Cause

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