How do I use Continuation field in /getTagData response?
Hello,
I am doing a rather large aggregate query against /getTagData which exceeds the maxSize of 1,000,000. The continuation property has a primitive array of three date times in it with no indication of what each date means. The documentation only shows random character strings in the continuation property, with no further information on what these values mean or how they should be used.
Obviously the dates mean something to the effect of a start date and end date, but I am a bit confused by the existence of a third date. Furthermore, IF I recall correctly, they were out of sequence - 4pm, 12am, then 4:30pm.
Can someone please help me make sense of these dates, and/or direct me to proper documentation/examples?
-
Hi jonathanhart. net ,
Thanks for the question! There is a lot to unpack here. First, there are two functions: /getTagData and /getTagData2.
/getTagData has a maxSize of 10,000. If the maxSize is not set, it defaults to this limit. If it is set above this limit, it will use 10,000 as the max instead. If the number of records exceeds this maxSize, it will return a continuation array. That array would need to be passed into the subsequent call so it knows where it left off. Now, there is a known bug with the continuation parameter. It only works when using the tags array parameter into the function (as opposed to using the path, deep, and search parameters). This is slated to be fixed in v23.1.
/getTagData2 has a default maxSize of 1,000,000. This is configurable if you have access to the historian server. By default, it is located in C:\Program Files\Canary\Views\CanaryViews.exe.admin.
This function should not return a continuation parameter as it is designed to be changed if needed so that you can get all of the data in one call. If you do see a continuation parameter being returned, that is a bug that has been fixed in the most recent release, v23.0. If you need the latest release, please contact support@canarylabs.com and provide them with your serial number. If you exceed the max with this call it should return the following message: "The maximum number of records per call has been exceeded. Max limit is: 1,000,000. Try modifying the query parameters to work within the limitation or contact your Canary administrator to adjust the limit."
Hope this helps!
Print this page