Application unknown issue after remanaging

It's likely that unmanaging and remanaging is simply exposing another underlying issue. How many component monitors are you currently monitoring on your Orion server?

We have 2009 component monitors. Out of that around 1500(all windows) are polled from one poller server.

Hmm.. That shouldn't be a problem. I'm going to ask that you put the monitored application in SAM into debug mode and reproduce the issue by unmanaging, then remanaging the application. Then collect a SolarWinds Diagnostic. Open a case with support and provide them the diagnostics so we can take a look at what's going on.

Thanks for your suggestion. But manually managing and unmanaging is not resulting in the same issue again. I think, this happens, when there is a bulk remanaging. Is there any way to see the deadlocks from any application logs? I am doubting DB issues. I want to check for some evidece from the application side. Where should I look to find it? Many of the view, which runs reports are not loading - It will stuck saying "loading". I guess, this also points to SQL issue.

If there were some deadlocks, there would probably be some error messages containing "deadlock" keyword in Application Data\Solarwinds\Logs\APM\APM.BusinessLayer.log or Application Data\Solarwinds\Logs\Orion\OrionWeb.log

There are also some performance counters for deadlock exposed by SQL server which can be collected to detect deadlocks. One of best ways to trace deadlocks is using SQL server profiler - it can be configured to collect only deadlock detailed data which can be useful for further investigation.

But in case of deadlock there is usually deadlock error message displayed in UI, so you would be certain...

You can also check APM.BusinessLayer.log for "Long processing" warnings which would be one of expected symptoms if there are some performance issues with SQL.