Unable to get session latch.
Snorri Bergmann (14.10.FC3, Linux) saw 'Unable to get session latch' performance advisories in online.log. Art Kagel said it is usually caused by applications that connect and disconnect frequently, notably Java apps. Andreas Legner added that frequent queries on sysscblst or syssessions can aggravate it. Snorri's apps are not Java but may connect often. No other fix was given.
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Hi. I'm running on 14.10.FC3 / Linux. Just saw a few occurrences of these in online.log: 10/08/20 16:45:22 Performance Advisory: Unable to get session latch. 10/08/20 16:45:22 Results: This can happen during high connectivity periods where sessions are allocated and freed frequently. 10/08/20 16:45:22 Action: This can impact session and tenant limits processing and low memory manager processing. 10/08/20 16:45:34 Performance Advisory: Unable to get session latch. 10/08/20 16:45:34 Results: This can happen during high connectivity periods where sessions are allocated and freed frequently. 10/08/20 16:45:34 Action: This can impact session and tenant limits processing and low memory manager processing. Any ideas what I can do to prevent this? The engine is running happily in spite of this. Thanks in advance, -Snorri ------------------------------ Snorri Bergmann ------------------------------ #Informix
Snorri: This is usually caused by Java apps that do not use persistent connections. Fix the apps and the problem goes away! Art Art S. Kagel, President and Principal Consultant ASK Database Management www.askdbmgt.com Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on 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.
Thanks Art. We do not have any Java apps connecting. However, it's possible we have apps that connect very frequently. Is that the main cause? Regards, -S ------------------------------ Snorri Bergmann ------------------------------
It can be, and it can be aggravated by frequent queries on sysscblst SMI table (or syssessions view built on top of that). ------------------------------ Andreas Legner ------------------------------
Yes, Snorri. Java apps are notorious for this, but other apps, especially those designed by folk who trained on SQL Server (SQL Server connect/disconnect is particularly cheap since most are local connections). that connect and disconnect frequently. Art Art S. Kagel, President and Principal Consultant ASK Database Management www.askdbmgt.com Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on 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.