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Host operating system was experiencing significant paging

martin_h Newbie
Currently Being Moderated
Hello,

I have a problem with many times discussing problem "Host operating system was experiencing significant paging but no particular root cause could be detected. Investigate processes that do not belong to this instance running on the host that are consuming significant amount of virtual memory. Also consider adding more physical memory to the host."

My database run on Windows Server 2008 R2 and have 12GB of physical RAM.

Oracle version is 10.2.0.4.0 and my sga and pga are:

sga_max_size 4000M
sga_target 3904M
pga 1200M

I try to find out something about this issue and read many blogs but unfortunately I didnt find anything which helped. Should this have something to do with the fact that on the server we have oracle database and terminal server with 30-40 users?

Any advice?

Thank you
Martin
  • 1. Re: Host operating system was experiencing significant paging
    Rob_J Journeyer
    Currently Being Moderated
    Hi,

    I've seen this a lot on Windows systems when there wasn't actually any problem. However, have you checked the basics, like how much memory you are actually using compared to how much is on the server?

    In any place that I have worked we'd never put a database instance on the same server where many users were running other applications. We would always have dedicated servers for our DBs. Sounds like a nightmare to me, as the users could potentially impact the performance if it's not managed very tightly. Just a thought.

    Have you used perfmon to see if there is anything obviously wrong?

    Rob
  • 2. Re: Host operating system was experiencing significant paging
    Rob_J Journeyer
    Currently Being Moderated
    Also, have a quick look at this thread:

    {thread:id=2177025}
  • 3. Re: Host operating system was experiencing significant paging
    martin_h Newbie
    Currently Being Moderated
    Hello,

    Thank you for your reply!

    Yes, it was a first thing I watched (RAM and perfmon - but nothing extraordinary). The physical ram is/was using on 60% so it is/was 8GB from 12GB... I also increase initial and maximum size of virtual memory, but it doesnt help...

    Yea, I know that installation like this is not correct, but you can do only what your customer want do, so... Each user run a lot of processes like explorer, forms and reprots client so this could be the reason for that? Moving users and terminal to another machine should help?


    Martin
  • 4. Re: Host operating system was experiencing significant paging
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    How did you identify excessive paging? What process or thread is causing page faults?

    And are these hard of soft page faults? (see Working Set for details)
  • 5. Re: Host operating system was experiencing significant paging
    martin_h Newbie
    Currently Being Moderated
    I found it a few days back, but nothing from this helped...
  • 6. Re: Host operating system was experiencing significant paging
    martin_h Newbie
    Currently Being Moderated
    Identify excessive paging from Performance Analysis from OEM...
  • 7. Re: Host operating system was experiencing significant paging
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    I suggest using performance monitoring tools provided by the o/s instead - and not OEM.

    OEM is useful. But it has its limits. To address "excessive paging" requires actual identification of the problem, and detailed analysis. OEM is a "generic" tool in that aspect. It does not understand the kernel in detail as the o/s provided performance tools do.
  • 8. Re: Host operating system was experiencing significant paging
    marksmithusa Journeyer
    Currently Being Moderated
    The alert log/OEM is getting its info from the v$ dynamic views. There is a known bug in 11gR2 whereby the v$ table is erroneously reporting paging (and the values are astronomical).

    As Billy said: trust your O/S monitoring. If all is OK there, ignore the DB messages.
  • 9. Re: Host operating system was experiencing significant paging
    martin_h Newbie
    Currently Being Moderated
    Thank you,

    I tried to get some information from ProcessExplorer but I didnt find anything that can cause this issue...

    Could this paging fault make slowdown database? I mean when users try to insert, update or delete data from tables, response of database is slow, sometimes in few seconds - in Oracle Database 9i we doesnt have this problems...
  • 10. Re: Host operating system was experiencing significant paging
    Rob_J Journeyer
    Currently Being Moderated
    As has already been suggested, maybe there is no fault. It's just being shown incorrectly by Oracle.

    Look at the sessions and quantify the slowness. Find out what they are waiting on. Use SQL tracing to see what is happening. Maybe the plans have changed in your new DB version?
  • 11. Re: Host operating system was experiencing significant paging
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    martin_h wrote:

    I tried to get some information from ProcessExplorer but I didnt find anything that can cause this issue...
    Oracle runs as threads. You should be looking at the oracle.exe process and its threads, the size of Vmem, and the number of soft and hard page faults errors per thread.

    This should tell you whether there is a page swapping issue for Oracle processing, and identify the threads experiencing the problem. With the threads identified, the associated Oracle v$process and v$session can be identified and analysed.
    Could this paging fault make slowdown database?
    Page swapping can make any process slow.
    I mean when users try to insert, update or delete data from tables, response of database is slow, sometimes in few seconds - in Oracle Database 9i we doesnt have this problems...
    Invalid comparison. Not the same database (physically). Not the same database software. Not the same anything.

    Saying that a 9i database was fast and a 11g database is not, is like saying the old green car was fast and the new car, also green, should therefore also be fast.
  • 12. Re: Host operating system was experiencing significant paging
    martin_h Newbie
    Currently Being Moderated
    Maybe not, but when I look at OEM and check the time of "Host operating system was experiencing significant paging" and than check this time in "Active Sessions Waiting" I can see that for example

    "UPDATE S_DZ SET PS_CENA=:1,ID=:2,S_KARTVOZ_ID=:3,S_DZVDOPR_ID=:4,VYK_MJ=:5,SPOTR_PHM=:6,CER_PHM=:7,CER_PHM_JC=:8,PS_MJ=:9,PS_PHM=:10,JC_PHM=:11,HODNOTA=:12,HODNOTA_SDPH=:13,POM_ODP_DPH_P=:14,DPH_P=:15,ST_PREN=:16,POS_UZIV=:17,PR_PS=:18 WHERE ROWID=:19" -> for example this update was run in time when OEM show "Host operating system was experiencing significant paging"

    I run SQL Tunning Advisor on this update - but then, there was no recommendation or the recommendation was not good - said our programmer

    How to check slowness in sessions? Is there any tutorial or something like that? Iam new to this ...
  • 13. Re: Host operating system was experiencing significant paging
    martin_h Newbie
    Currently Being Moderated
    Thank you for reply Billy Verreynne,

    I will try to check v$process and v$session, but for first I need to find something about it, because its new to me...

    I dont want to say that older version of Oracle was better, definetly not, I like new versions of Oracle Products... I only want to say that our app was going better on older platfrom...
  • 14. Re: Host operating system was experiencing significant paging
    BillyVerreynne Oracle ACE
    Currently Being Moderated
    martin_h wrote:

    I dont want to say that older version of Oracle was better, definetly not, I like new versions of Oracle Products... I only want to say that our app was going better on older platfrom...
    Granted. But one cannot compare one system (old/new) with another (old/new). Such a comparison requires a mutually common baseline. This does not exist. And is very complex to create. So performance comparison of one system/server with another is very seldom valid, never mind actually useful.

    The 1st step in dealing with a performance issue is to identify exactly what the problem is. You have not identified page swapping as the actual problem. The OEM report on excessive swapping alone does not suffice - at best it is reporting a symptom.

    Each process/thread has "private" memory (stack, heap, text, etc space). Memory can also be "public", as in the Oracle SGA.

    You will need to establish what memory are being excessively swapped, and by which process, in order to identify the problem.
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