Re: MMON_SLAVE seems high CPU with "select longname from javasnm$ where short = :1"

High Database Traffic Seen In Table javasnm$ (Doc ID 2060224.1) Bug 14755810 : LIBRARY CACHE PIN ON SELECT LONGNAME FROM JAVASNM$ WHERE SHORT = :1 (92 - Closed, Not a Bug)

Regards
Dimitre

On 01/12/2015 09:53, Kim Berg Hansen wrote:
> Hi, List
>
> We have a database Oracle Database 11g Enterprise Edition Release
> 11.2.0.3.0 - 64bit Production on Oracle Linux Server release 6.5 with
> 4 cores.
>
> One statement seems to practically continously use 20% of a core when
> I look at top activity in Cloud Control (or Enterprise Manager or
> whatever it is called):
>
> selectlongname
> fromjavasnm$
> whereshort=:1
>
> All of it executed by a single session with Module=MMON_SLAVE,
> Action=JAVAVM JIT slave action.
>
> We do use some Java and XML in the database, but I do not believe it
> to be huge amounts.
> Besides, I would think then it would be executed in user processes and
> not this single background process?
>
> I have tried to enable trace for the session in order to examine bind
> variable content to find out which Java identifiers are being looked up.
> But no trace file is created in the usual place? (The session also has
> AudSid=0 and AudSid usually is part of trace file name as far as I know.)
>
> Q1: Are trace files from background processes placed in other
> directory? If so, where can I find which directory?
>
>
> The wait event for the session seem to be JOX Jit Process Sleep.
> As far as I can tell it is an idle event.
> MOS note 1075283.1 describes it might show up in top list as a bug in
> 11.1 that should be fixed in 11.2.
>
> Q2: Is it possible the 20% of a core CPU expenditure shown in Cloud
> Control is not actually CPU expenditure but wrongly reported?
>
>
> Q3: Any suggestions for how to dig into what actually is happening
> with that statement?
> (Keeping in mind I am primarily a developer ;-)
>
>
> Thanks in advance for any hints I might use for further digging.
>
>
> Regards
>
>
> Kim Berg Hansen
>
> http://www.kibeha.dk
> kibeha_at_kibeha.dk <mailto:kibeha_at_kibeha.dk>
> _at_kibeha <http://twitter.com/kibeha>
>

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