system.historian.queryRawPoints(...) vs system.tag.queryTagHistory(..)

[Jorge_Dalzotto]

Hi guys,

I found some unexpected behavior with these two “equivalent” functions.

I’m using the “long path” format ([db_connect/project_name:provider]PathTag) to access the historian of different systems, and I noticed that it no longer works as before in scripting (although it does work in the Easy Chart component).

(same input-->different output)

Is this a bug, or is this the “new” working format? In the latter case, is there a workaround for this situation?

Best regard

[Jorge_Dalzotto]

Hi, I can resolved (in theory - I still need to run some tests) the problem...but I comment ones topics:
There are another format (maybe new) for history path for a "system.historian" functions:

The old format was:

[<histprov>/<gatewayName>:<provider>]<tag_path>

And the “new” format is:

<histprov>:mariadb:/sys:<gatewayName>:/prov:<provider>:/tag:<tag_path>

Also, system.historian.queryRawPoints(...) does not have the aggregationModes parameter, but there is a new function, system.historian.queryAggregatedPoints(...), which is useful for my purposes.

(Maybe this will be useful for someone).

[pturmel]

There are three tag path formats relevant here:

• Basic Tag Paths with just a tag provider,
• Basic Tag Paths with historian+gateway+tag provider stuffed into the provider brackets, and
• Qualified Paths with a flexible expanded format.

The first format just delegates to the tag provider to supply the actual details needed to find the history. The other formats must spell it all out. The newer QualifiedPath format was created for 8.x and is the preferred form in Perspective. The expanded Basic TagPath format is the legacy Vision format.

Scripts are supposed to accept all three.

Discussion here with more details (and further links):

Historical Tag Provider Issues

I will start with what I am trying to accomplish here first. So I have a dynamic tag history binding using the model from the manual. key [array] [0] {object} aggregate value alias value path value [1]{object} aggregate value alias value path value ... Now I have done this same thing other places so I know that portion is correct. But when I have a tag path in there. I get the all mysterious: "No historical tag information could be found for any of the specified paths" showing up …

If the "old format" is broken for you (in scripts), that is a bug that should be reported. I'm not really sure how well Perspective is supposed to support the 2nd form, or how well Vision is supposed to support the 3rd form. Documentation is lacking, and firm details to even write the documentation is hard to find.