Database Lock in GEO Scada

[BGedco2022]

Dear All,

We' ve faced database lock twice in lesss than month!!!

What could be the cause, how can we resolve it?

we also noticed DB interest high at user time 71.3% compared to server time 0.7#%

Is this normal?

 We'll be grateful for any guidance or hints

thanks in advance

[sbeadle]

A database lock alarm is not necessarily a problem, it does mean that you should review database configuration, system loading and PC resources to see if there are improvements. For example, you may get a lock alarm occurring when report queries are running, and you could spread the execution of reports out.

The DB Interest thread % should be looked at in the context of the other items in the logs, such as OPC DA Items etc.

If you require further help I suggest you contact the SE support team. They can advise on the interpretation of lock statistics in database snapshot log files.

[du5tin]

We have been troubleshooting high DB lock with multiple large systems for the past few months, most of them virtualized. Interest/Lock with 70%+ peaks happening occasionally is not necessarily a problem but high sustained lock % can often indicate something is amiss. 

Things we look for: 

- misconfigured or high number of Logic programs (usually its logic programs that do config and run at the default once a second)

- overactive points

- system loading (CPU usage, disk usage, etc.) 

With virtual based systems we are now looking at CPU Ready. This is a VMware metric showing the amount of time a VM is waiting for processing time on the virtual host. I am not sure if Hyper-V or cloud platforms have a similar metric. This is not always something that is a contributing factor, but is worth looking at. More vCPUs to relieve "load" isn't always better if the virtual host is heavily loaded. It has been our experience if the VM host is over subscribed and the VMs are busy that this contributes to a higher DB lock than is typical. 

There are some queries and suggested design docs in the resource center that you can reference for more info. But to dig deep you will likely want to call tech support who will take you through the basic steps to troubleshoot consistent high DB lock %. https://community.se.com/t5/Geo-SCADA-Knowledge-Base/System-Setup-and-Troubleshooting/ba-p/279093