When going to the Query View of the NHaystackService, and running a query on lets say "outside and temp", the curVal of the points aren't leased so they show old data. Shouldn't the Query invoke a lease on the points it brings in?
Mike JarmyTue 22 Apr 2014
That's something I've never considered before. I'm hesitant to do it because if you queried for "point" you'd end up subscribing every single point, which is probably not something you'd want to do.
Christopher HowardTue 22 Apr 2014
That is a good point. I am still trying to find my place in the haystack world and currently I am looking at how my customers could benefit from the built in query. The bql query builder leases points when run, and yes you have the potential to cause your system to gasp for air when your query is too vague, but what's the point of running a query on something that gives you "curVal" ,"curStatus" when the data you get back is not current? Just a suggestion, but could there be a slot added that allows you the option to select whether your points are leased or not?
Mike JarmyTue 22 Apr 2014
I think the best way to think of that Query View is just as an informational tool that allows you to use workbench to investigate what your station looks like in haystack-speak.
You can subscribe to those points, you would just do it from another computer that is connected to your station. If you contact your station over HTTP you can put the points in watch, which will cause them to subscribe.
As it is now, workbench does not mimic that functionality. I think I'd rather leave it like that, because everyone is used to the way it works, and I don't want to make a change that would cause all that inadvertent mass point subscription, which would really cause major problems in a production system.
Jason BriggsTue 22 Apr 2014
I'm pretty sure that BQL does not subscribe to points, in fact I'm almost positive it doesn't. Unless that has been changed in the last update. If it did this could be a potential problem.
If you use 3rd party tools, they can do this automatically for you. IE... You could pick what gets subscribed and what doesn't get subscribed.
Christopher HowardTue 22 Apr 2014
Jason,
you are correct. I don't know were my head was at the time I wrote this. I have written some subscription programs to help me with this in the past. It shouldn't be too hard to modify it for the Query View.(if I want to go that route)
Christopher Howard Tue 22 Apr 2014
When going to the Query View of the NHaystackService, and running a query on lets say "outside and temp", the curVal of the points aren't leased so they show old data. Shouldn't the Query invoke a lease on the points it brings in?
Mike Jarmy Tue 22 Apr 2014
That's something I've never considered before. I'm hesitant to do it because if you queried for "point" you'd end up subscribing every single point, which is probably not something you'd want to do.
Christopher Howard Tue 22 Apr 2014
That is a good point. I am still trying to find my place in the haystack world and currently I am looking at how my customers could benefit from the built in query. The bql query builder leases points when run, and yes you have the potential to cause your system to gasp for air when your query is too vague, but what's the point of running a query on something that gives you "curVal" ,"curStatus" when the data you get back is not current? Just a suggestion, but could there be a slot added that allows you the option to select whether your points are leased or not?
Mike Jarmy Tue 22 Apr 2014
I think the best way to think of that Query View is just as an informational tool that allows you to use workbench to investigate what your station looks like in haystack-speak.
You can subscribe to those points, you would just do it from another computer that is connected to your station. If you contact your station over HTTP you can put the points in watch, which will cause them to subscribe.
As it is now, workbench does not mimic that functionality. I think I'd rather leave it like that, because everyone is used to the way it works, and I don't want to make a change that would cause all that inadvertent mass point subscription, which would really cause major problems in a production system.
Jason Briggs Tue 22 Apr 2014
I'm pretty sure that BQL does not subscribe to points, in fact I'm almost positive it doesn't. Unless that has been changed in the last update. If it did this could be a potential problem.
If you use 3rd party tools, they can do this automatically for you. IE... You could pick what gets subscribed and what doesn't get subscribed.
Christopher Howard Tue 22 Apr 2014
Jason,
you are correct. I don't know were my head was at the time I wrote this. I have written some subscription programs to help me with this in the past. It shouldn't be too hard to modify it for the Query View.(if I want to go that route)