Re: Blocking sessions related to client process
- From: Tanel Poder <tanel@xxxxxxxxxx>
- To: Oracle-L Freelists <oracle-l@xxxxxxxxxxxxx>
- Date: Wed, 29 Sep 2010 16:07:06 +0300
JDBC Thin drivers always set the client process to 1234 as thin drivers,
being fully contained within JVM, don't have a way to find out the PID of
the JVM process itself. Someone JDBC developer in the java world figured
that a good number for specifying "unknown" value is 1234, instead of 0 or
-1.
In such case you can identify the SPID of the database process, run lsof (or
pfiles if on solaris) on the process to see to which IP/port combo it's
talking to. Then log on to that IP and run lsof there to see which process
uses that peer port... this won't work well with connection pools though...
--
Tanel Poder
http://tech.e2sn.com
http://blog.tanelpoder.com
On Wed, Sep 29, 2010 at 3:06 PM, <Joel.Patterson@xxxxxxxxxxx> wrote:
> Any help would be appreciated.
>
> I respect and appreciate every ones time. If this is considered to basic
> a question, then perhaps pointing me to the right place would be helpful
> because I can’t find the right docs or get to the bottom of this. It
> should be more of a clarification as I have been doing this a long time,
> so I figure I’m missing something.
>
> The person asking me was using EM, and saw 4 blocking locks, (in the
> blocking sessions section), and in the client section he sees OS process
> 1234 but cannot grep for this process on the client machine. He wants to
> go from the blocking sessions in the database (jaxlawdw), and link to the
> corresponding process on the client machine.
>
> The person says that it is always client process 1234 as indicated in
> enterprise manager ‘blocking sessions’ , ‘session details’, ‘Client’, ‘OS
> Process ID’. The person believes it is a ‘fake’ or phantom process.
>
> How do I help, as I may not be giving the correct explanation, else we
> should see the process on the client machine?
>
> Example of first row when combining v$session and v$process, shows s.sid
> 486, p.pid 47, p.spid 8105, and s.process 1234.
>
> Note when querying these two tables for s.process 1234 it returned 58 rows,
> (but this was done then next day and not live when the blocking sessions
> where happening).
>
> Session Process p.pid p.spid Session
>
> SID Serial# Serial# Ora ProcID OS ProcID Process Session
> Username OS Username STATUS MACHINE Process Program
>
> ------ ------- ------- ---------- ------------ ------------
> -------------------- ------------ -------- --------- ----------------------
>
> 486 36738 136 47 8105 1234
> GENTRAN b2badmin INACTIVE jaxb2bprd oracleGISPROD@jaxlawdw
>
> Joel Patterson
> Database Administrator
> 904 727-2546
>
>
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