Experimental Physics and
Industrial Control System

Ralph Lange <[email protected]> · Fri, 03 Apr 2015 16:29:18 +0200

Hi,

We ran into some trouble when sending small arrays (64 bit total size)

at high rate from an IOC.

Background: Our timing card generates 64 bit timestamps. When these are

being treated as a value, the only way to implement them in the IOC

database (<=3.15) is as an array of two 32bit elements.

With the help of Mark Rivers (who was adding configurable queuing for

arrays to ASYN) we manged to fix the event leak between driver and

database. Now we're hitting the leak between database and the rsrv CA

server: updates to arrays (and strings) are put in the event queue by

reference, so all queue entries are pointing to the same array instance

and wrong data is being shipped to the client without any hint that the

data is wrong.

Looking for a minimally invasive fix...

Would you think it is possible and a good idea to base the queuing type

decision (by value or by reference) on the size instead of the DBF type,

so that arrays <= 64 bit total length (or maybe a configurable value)

are put in the queue by value?

That would solve our issue, and not create too much exceptionalism, right?

Cheers and Happy Easter,
~Ralph

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System