Hi guys, been a while since I visited the portal... I have a question which you may be able to answer here but if not then I'll forward it onto the support team.
What is the normal latency when issuing a dpGetPeriod() command to retrieve in the region of 2700 readings over a period of 28 days from a WinCC-OA system? I know it's a bit like asking how long is a piece of string, but it doesn't seem like such a massive request to me for an Oracle database to deal with but it is still taking in the region of 10-15 seconds to return the result. I have also noticed that when plotting data on a trend (and changing zoom extent), there can be a significant delay before anything is rendered.
We are running 3.10 with all the patches applied and the servers have 1Gbit network interfaces. There has hardly been any other activity in the system when I have tried this... I have also tried switching to dbquerydirect but it doesn't seem to make any difference.
The Orancle instance doesn't seem to be the bottleneck as a similar request using SQL completes in less than a second.
dpGetPeriod() latency
- leoknipp
- Posts:2928
- Joined: Tue Aug 24, 2010 7:28 pm
Re: dpGetPeriod() latency
Hello,
it is not possible to tell you how long a dpGetPeriod()-call can take.
There are many factors which have an influence to the time to answer a dpGetPeriod-call, e.g. used hardware, operating system, current load at the system, type of used database, timerange which has to be read, number of entries in the result table.
When using the UI to display the historical information there are two steps which need to be processed by the system:
-- reading data from the database
-- displaying data in the user-interface
To be able to give you a detailled answer we need more information, e.g. logfiles with activated debug-flags, debugs from the script.
Please open an official support request, then we can tell what you have to do.
Best Regards
Leopold Knipp
Senior Support Specialist
it is not possible to tell you how long a dpGetPeriod()-call can take.
There are many factors which have an influence to the time to answer a dpGetPeriod-call, e.g. used hardware, operating system, current load at the system, type of used database, timerange which has to be read, number of entries in the result table.
When using the UI to display the historical information there are two steps which need to be processed by the system:
-- reading data from the database
-- displaying data in the user-interface
To be able to give you a detailled answer we need more information, e.g. logfiles with activated debug-flags, debugs from the script.
Please open an official support request, then we can tell what you have to do.
Best Regards
Leopold Knipp
Senior Support Specialist
- aorange
- Posts:147
- Joined: Thu Nov 04, 2010 10:07 am
Re: dpGetPeriod() latency
Thanks Leopold, I will open a support request... I am experiencing similar delays when updating the alert range on datapoints as well. Could be a database problem.