Hello - is there a maximum number of elements allowed in PI AF? Or a limit per hierarchy?
As far as I'm aware there is nohard limit on number of elements that can be created in a single hierarchy. For better performance we generally restrict between 6-10 levels and based on business functionality. But interms of performance i will always recommend to restrict number of level as much as possible without impacting business view.
Performance aspect :
AFElement.FindElementsByPath Method (IEnumerable(String), AFObject)
The performance of finding elements by path can vary depending on the syntax, server version, path length and hierarchy depth. For best performance, make sure you are using the latest AF Server. Simple relative paths (no substitution or navigation up or across the hierarchy) will perform better. Element paths which exceed a length of 420 characters or a depth of 24 levels will execute slower.
I'll also add to Lal's response that while there may not be any known software limitations for max number of AF elements, hardware must be appropriately sized for the SQL server. As Lal mentions, hierarchy can also have a big impact - for example, if you have a flat hierarchy with a large number of elements at root level it also may not run as well as having something more broken up and you may see performance issues within PI System Explorer - so this should be kept in mind when considering 'limit per hierarchy'.
How many elements were you thinking and how will the data be consumed by clients?
And to add to Emily and Lal, please refer to for proper system sizing: https://techsupport.osisoft.com/Downloads/File/8d7f6f38-2ed3-43f3-a7f5-a15789e6bca7?_ga=2.250644160.776872591.1535376635…
Thanks for all your responses. In relation to number of elements: best case 9000, worst case 1 million. We would break these up to at least two levels, probably three (region -> area -> load measurement point).
I think the # of levels is not that relevant as that does not impact performance directly, only if you need to traverse more, you need to cover more distance which takes performance.
Wrt to the size, in addition to the Excel sizing sheet, there is also a tool here: https://techsupport.osisoft.com/Troubleshooting/hardwaresizing/
That is quite happy consuming 2M Elements, but that does have it's impact on SQLserver recommendations. But hey, hardware is cheap compared to labour in performance improvements.
We have customers that have over 1 million elements in their AF Server and running without any issues. As Roger said, properly sizing the hardware, especially the SQL Server, will be important to ensure performance at scale.
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