Increase or remove the character limit in the OASyS-PI Interface. Merged

See also: SR 103173241

When defining a PI tag that sources data using the ‘Generic PubSub’ method (Location2 = 15), our custom developed PubSub Persistence Store receives a subscription for an incomplete topic string.

Example:

• Using a PI tag I am attempting to read the PubSub topic: pdss.accumculator.track.period_day.virtualflowcomputer.SM_TOTAL_PA.gsv.calctotal

• Using debug logging in the custom Persistence Store application, I can see that the OASyS-PI interface subscribes with the topic string: pubsub.subscription.pdss.accumculator.track.period_day.virtualflowcomputer.SM_TOTAL.add_integ.ac11b829.211800000001

  • Note that the subscribed topic string is missing the ‘_PA.gsv.total’ portion.

• This topic string works fine if one uses the MultiSubscriber tool

GCS Analysis:

There does appear to be a limit to subscription length in PIOASyS.

As far as I can determine, under the code path Pembina is using the subscription they are trying to use is being placed in pioasysptr->field which is declared as a FieldString. FieldString is in turn defined as char[64]

I don't think it is a coincidence that pdss.accumculator.track.period_day.virtualflowcomputer.SM_TOTAL is a 64 char string (if NUL terminated).

From libpioasys:

typedef char FieldString[64];   // OASyS field name specifier

typedef char NameString[32];    // OASyS DB or point name specifier

typedef char ErrString[255];    // Error or message string

typedef char PubSubTopic[255];  // PubSub topic 

typedef char *pPIDataString;    // pointer to a PI data string



/* Definition of structure for principal developer structure */ 

typedef struct { 

   pioas_err error; 

   pioas_dtype dtype; 

   NameString table;

   NameString key;

   FieldString field;

   path pth;

   oas_boolean_t    subscribedTo;

   oas_time_t   lastUpdate;  // time that last update was retrieved

   void * pCnvFunc; /* point to the data conversion function */

   void * pDQFunc; /* point to the data quality re-map function */

   void * pPSMsgFunc; /* point to the PubSub message handler function */

   doas_dset_slot dataset; /* dataset slot number of a point */

   PubSubTopic psTopic; /* PubSub topic subscribed by this point */

} pioaspt, *pioasptr; 

Request:

Pembina would like this length limitation for PIOASyS to be increased or removed. As noted, the longer subscription string works in the MultiSubscriber so the length limit is not inherent in the PubSub implementation.