wait statistics - meaning of mt yield

Hello, can anyone explain the meaning of 'mt yield' when examining the IDS wait statistics? The wait reason 'mt yield' is far on top. Somewhere I found the explanation 'mt yield' means 'waiting for client'. But IDS an application are running on the same box and there is always some CPU idle. Any suggestions appreciated. Regards, Andreas Kutsche

Andreas, I'm guessing "mt yield" is a mutex thread yield... This wouldn't matter if your app and DB are on the same box or not. IF this is a mutex thread yield... i think a mutex lock/latch is like an atomic/internal lock.... not the typical lock seen by "onstat -k". I reserve the right to be wrong, and look forward to other explanations :) Norma Jean -----Original Message----- From: andreas.kutsche@spar.at [mailto:andreas.kutsche@spar.at] Sent: Thursday, December 04, 2003 4:01 AM To: ids@iiug.org; forum.subscriber@iiug.org Subject: wait statistics - meaning of mt yield [2289] Hello, can anyone explain the meaning of 'mt yield' when examining the IDS wait statistics? The wait reason 'mt yield' is far on top. Somewhere I found the explanation 'mt yield' means 'waiting for client'. But IDS an application are running on the same box and there is always some CPU idle. Any suggestions appreciated. Regards, Andreas Kutsche ----------------------------------------- ============================================================ The information contained in this message may be privileged and confidential and protected from disclosure. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any reproduction, dissemination or distribution of this communication is strictly prohibited. If you have received this communication in error, please notify us immediately by replying to the message and deleting it from your computer. Thank you. Tellabs ============================================================

You can yield for many reasons. For instance, the client is trying to read a row that is currently locked by some other transaction. "ANDREAS KUTSCHE" <andreas.kutsche@ To: ids@iiug.org spar.at> cc: Sent by: Subject: wait statistics - meaning of mt yield [2289] forum.subscriber@ iiug.org 12/04/2003 02:01 AM Hello, can anyone explain the meaning of 'mt yield' when examining the IDS wait statistics? The wait reason 'mt yield' is far on top. Somewhere I found the explanation 'mt yield' means 'waiting for client'. But IDS an application are running on the same box and there is always some CPU idle. Any suggestions appreciated. Regards, Andreas Kutsche

Sorry, but I can't get the meaning of your explanation: Does that mean 'yield' is a different kind of 'wait' ? Because when extracting wait statistics there are (different) entries with reason 'lock' or 'mutex' . Therefore what is the difference between the wait reason 'yield' and 'lock'? Regards, Andreas Kutsche

If wait statistics is off the onstat -g ath output knows a state "sleeping forever". Threads enter it if they wait for something to happen in some other thread. The other thread is responsible to wake them up then. This state is used for many different things. Among them are waiting for buffer, lock, and io. If you enable wait statistics the server differentiates this state further into more explicit wstat states like buffer, lock, aio (see sysmaster.sql "Session waits reasons"). If you get "mt yield" it means that you are waiting for something that is not one of the other wait reasons like buffer, lock, etc. If you need to know what it is you could try and do a "onstat -g stk <tid>" on a thread you caught in this state and send me the stack trace. I will try and tell you what is is. Regarts Michael ANDREAS KUTSCHE wrote: > Sorry, but I can't get the meaning of your explanation: > > Does that mean 'yield' is a different kind of 'wait' ? Because when extracting wait statistics there are (different) entries with reason 'lock' or 'mutex' . Therefore what is the difference between the wait reason 'yield' and 'lock'? > > Regards, > Andreas Kutsche > > > -- === Michael Mueller ================== Tel. + 49 8171 63600 Fax. + 49 8171 63615 Web: http://www.mm.kay-mueller.de http://www.planets.kay-mueller.de ======================================