RE: Swapping Issues and ora_dbw

From: Hilton Meyer <hilton_at_komit.co>
Date: Wed, 8 Oct 2014 05:28:31 +0000
Message-ID: <93ba4b7b7be444aeb2a87605428a0078_at_AM3PR06MB404.eurprd06.prod.outlook.com>

Here is the full commands and outputs:

# top -c
top - 08:15:23 up 26 days, 21:15, 4 users, load average: 1.80, 2.20, 2.55 Tasks: 613 total, 5 running, 608 sleeping, 0 stopped, 0 zombie Cpu(s): 20.3%us, 3.9%sy, 0.0%ni, 68.2%id, 7.4%wa, 0.0%hi, 0.1%si, 0.0%st Mem: 49557132k total, 49264636k used, 292496k free, 49236k buffers Swap: 8257532k total, 7888592k used, 368940k free, 42721744k cached

  PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND

49069 oradev    20   0 12.2g  10g   9g S  0.0 21.2  41:58.61 ora_dbw0_DEV
49073 oradev    20   0 12.2g   9g   9g S  0.0 21.1  41:58.67 ora_dbw1_DEV
 4716 orapatch  20   0 12.2g 8.5g 8.5g S  0.0 17.9  34:21.58 ora_dbw1_PATCH
 4712 orapatch  20   0 12.2g 8.5g 8.4g S  0.0 17.9  32:42.16 ora_dbw0_PATCH

.
.
.

# free -m

             total       used       free     shared    buffers     cached
Mem:         48395      48106        288          0         55      41525
-/+ buffers/cache:       6525      41870
Swap:         8063       7724        339

Thanks,

Hilton Meyer
Database Administrator

Phone: +972-52-7908599
Office: +972-52-7908600 Fax: 1535-27908600 hilton_at_komit.co | www.komit.co<http://www.komit.co/>

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From: Mark W. Farnham [mailto:mwf_at_rsiz.com] Sent: Tuesday, October 07, 2014 5:40 PM
To: Hilton Meyer; oracle-l_at_freelists.org Subject: RE: Swapping Issues and ora_dbw

1. tell us the command (some variety of ps?)
2. give us a head -2 of the command results so we can see the headings as well as the lines you care about
3. without knowing the tool, is it one that reports the combined sum of memory used by the process as well as any shared memory attached during its run? IF so, then easily up to your sga size could be a complete red herring in considering the amount of memory a process is holding

From: oracle-l-bounce_at_freelists.org<mailto:oracle-l-bounce_at_freelists.org> [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Hilton Meyer Sent: Tuesday, October 07, 2014 5:25 AM
To: oracle-l_at_freelists.org<mailto:oracle-l_at_freelists.org> Subject: Swapping Issues and ora_dbw

Hi there,

I have a test server with three instances running and I have been seeing that swapping issues. The server is running out of swap space, been flirting on the edge of 0. I dug a little deeper an found that the main culprits are two of the instances:

49069 oradev    20   0 12.2g  10g  10g S  0.0 21.5  40:44.19 ora_dbw0_DEV
49073 oradev    20   0 12.2g  10g  10g S  0.0 21.5  40:43.90 ora_dbw1_DEV
 4716 orapatch  20   0 12.2g 8.5g 8.5g S  0.0 17.9  33:20.19 ora_dbw1_PATCH
 4712 orapatch  20   0 12.2g 8.4g 8.4g S  0.0 17.9  31:45.49 ora_dbw0_PATCH

The weird thing is the third instance does not register although they are the same clone from the Production instance. Few questions:

• Is this not an unusually high percentage of memory for the process to hold?
• Is there a way to release the memory back to the server?
• Is there a way for me to dig deeper to find out why these two instances are holding so much memory?

Sys Info:
EBS R12.1.3
Oracle Database 11g Enterprise Edition Release 11.2.0.3.0 - 64bit Production Linux 2.6.39-400.210.2.el5uek

Thanks,

Hilton Meyer
Database Administrator

Phone: +972-52-7908599
Office: +972-52-7908600 Fax: 1535-27908600 hilton_at_komit.co<mailto:hilton_at_komit.co> | www.komit.co<http://www.komit.co/>

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Received on Wed Oct 08 2014 - 07:28:31 CEST