IDS Forum

Re: Locked Mutex session - freezing instance

Posted By: Cesar Inacio Martins
Date: Friday, 4 February 2011, at 5:34 a.m.

In Response To: Re: Locked Mutex session - freezing instance (Art Kagel)

Hi Art and Fernando,

So, unfortunatelly we could have time to generate a full dump at the moment, only a fews onstat are generates.
We started onstat -a , onstat -g all , onstat -g stk all . But keep more the

Art,
The sentinel is in other machine (windows), accessing the database over SOCTCP .

12 CPUvps
NETTYPE ipcshm,3,450,CPU # Configure poll thread(s) for nettype
NETTYPE soctcp,3,450,NET # Configure poll thread(s) for nettype
DBSERVERNAME xyz # Name of default database server
DBSERVERALIASES abc_soc # List of alternate dbservernames

xyz onipcshm host1 xyz_shm
abc_soc onsoctcp host1 abc_soc

At the moment we have no more of 500 sessions..

Cesar

--- Em qui, 3/2/11, Art Kagel <art.kagel@gmail.com> escreveu:

De: Art Kagel <art.kagel@gmail.com>
Assunto: Re: Locked Mutex session - freezing instance [22696]
Para: ids@iiug.org
Data: Quinta-feira, 3 de Fevereiro de 2011, 15:03

How many processor cores? How many CPU VPs configured? What are the
NETTYPE, SERVERNAME, and DBSERVERNAME parameter settings from your ONCONFIG
file? What are the relevant sqlhosts file entries for this server? Is
Sentinel also running locally on the server?

Art

Art S. Kagel
Advanced DataTools (www.advancedatatools.com)
IIUG Board of Directors (art@iiug.org)
Blog: http://informix-myview.blogspot.com/

Disclaimer: Please keep in mind that my own opinions are my own opinions
and
do not reflect on my employer, Advanced DataTools, the IIUG, nor any other
organization with which I am associated either explicitly, implicitly, or by
inference. Neither do those opinions reflect those of other individuals
affiliated with any entity with which I am affiliated nor those of the
entities themselves.

On Thu, Feb 3, 2011 at 11:15 AM, Cesar Inacio Martins <
cesar_inacio_martins@yahoo.com.br> wrote:

> Hi
>
> AIX 5
> IFX 10 FC4
>
> We had a situation here where the instance froze in a way which commands
> ONMODE no longer worked and freeze the open connection of new sessions.
> Any ONMODE command executed, just freeze.
>
> After found the suspect session what freeze everybody , we just could not
> killed it
because the onmode don't worked too.
> The solution was restart the server.
>
> My question is, situations like these, is there other way to force kill the
> session?
>
> The suspect session was appear be from our sentinel , where at this moment
> have a sqltrace active over a session. This session (sentinel) just keeped
> with running+reading state .
> The lock occur over the mutex "session" . For what is used this mutex?
>
> Moslty of the user access to the database is with IPCSHM and only few users
> with SOCTCP. But almost of users was locked on this mutex, just a couple of
> users keep running.
>
> Here is some output saved :
>
> > head -n 20 onstat.gwmx.out
>
> IBM Informix Dynamic Server Version 10.00.FC4 -- On-Line -- Up 6 days
> 01:03:28
> -- 7663184 Kbytes
>
> Mutexes with waiters:

> mid addr name holder lkcnt waiter waittime
> 12 70000000009c030 session 2494402 0 2516947 1639
>
> 2506557 1637
>
> 16 1636
>
> 2495653 1635
>
> 2516831 1635
>
> 20 1635
>
> 2516844 1635
>
> 2516915 1633
>
> 18 1633
>
> 14 1630
>
> 2516958 1622
>
> 2516830 1615
>
> 2516866 1605
>
> 2490871 1603
>
> 2514053 1599
>
> >grep 2494402 onstat.ath.out
> 2494402 7000001afde96c8 7000001bc336d68 2 running 5cpu sqlexec
>
> >grep 7000001bc336d68 onstat.u.out
>
> 7000001bc336d68 ---PR-- 262700 informix - 0 0 1 10 0
>
> >cat onstat.gsql.out
>
> IBM Informix Dynamic Server Version 10.00.FC4 -- On-Line -- Up 6 days
> 01:17:58
> -- 7663184 Kbytes
>
>
Sess SQL Current Iso Lock SQL ISAM F.E.
> Id Stmt type Database Lvl Mode ERR ERR Vers Explain
> 262700 SELECT sysmaster CR Not Wait 0 0 9.03 Off
>
> Current statement name : _ifxc00000000003fx
>
> Current SQL statement :
> select t2.cbl_sessionid session_id, cbl_stmt[1,691] prpstm, t2.cbl_estcost
>
> sqs_estcst, t2.cbl_estrows sqs_estrws, t2.cbl_seqscan sqs_seqscn,
>
> t2.cbl_autoindex sqs_autoidx, t2.cbl_tempfile sqs_tempfls, cbl_sdbno
>
> seqnum from sysmaster:'informix'.sysconblock t2 where
>
> cbl_ismainblock='Y' AND length(cbl_stmt) between 190 AND 691 and
>
> t2.cbl_sessionid in (244926)
>
>
>
>
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Messages In This Thread

• Locked Mutex session - freezing instance
  Cesar Inacio Martins -- Thursday, 3 February 2011, at 11:15 a.m.
  • Re: Locked Mutex session - freezing instance
    Fernando Nunes -- Thursday, 3 February 2011, at 11:31 a.m.
  • Re: Locked Mutex session - freezing instance
    Art Kagel -- Thursday, 3 February 2011, at 12:03 p.m.
    • Re: Locked Mutex session - freezing instance
      Cesar Inacio Martins -- Friday, 4 February 2011, at 5:34 a.m.

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