[jira] Commented: (UIMA-838) Incorrect support for process CAS error threshold count and threshold window

["Marshall Schor (JIRA)" <ui...@incubator.apache.org>]

    [ https://issues.apache.org/jira/browse/UIMA-838?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12574560#action_12574560 ] 

Marshall Schor commented on UIMA-838:
-------------------------------------

I agree this seems an issue.

There seems to be several concerns here.  Above you have stated what the current "documentation" says.  What does the current implementation do?

Is it documented what the meaning of 0 being supplied for the Window and/or the thresholdCount means?  (I looked in the docbooks for uima-as - and didn't see it in the reference chapter).

Thresholds have two common meanings - one is something to be "reached", the other is something to "cross".  I think that the more common meaning that would come to mind (at least for English speakers) is the "crossed" idea.  (Do others agree?)

So if the underlying issue is that the current docs and implementation do not have a way to specify taking action on the occurence of the 1st error, then we might want to explore solving this in other ways that might preserve the common meaning of threshold.

A design goal I like for the XML we expose to our users is having that XML be as intuitively obvious to users, who might not be "familiar" with the "corner cases".  One possible approach to this problem is to change the meaning of 0 for thresholdCount to mean take action when crossing from 0 to 1, and recover the previous meaning of 0 (ignore errors) in some other fashion - 2 examples being

thresholdCount="ignore errors"
thresholdCount="-1"

(Or both).  The "ignore errors" value would be intuitively obvious to a casual reader of the XML.  The -1 value would something a reader would not have an immediate intuition for, and they would more likely "look it up".

> Incorrect support for process CAS error threshold count and threshold window 
> -----------------------------------------------------------------------------
>
>                 Key: UIMA-838
>                 URL: https://issues.apache.org/jira/browse/UIMA-838
>             Project: UIMA
>          Issue Type: Bug
>          Components: Async Scaleout
>            Reporter: Burn Lewis
>
> The thresholdAction should be taken when the number of CAS errors reaches the thresholdCount value within the last thresholdWindow CASes.  A thresholdWindow of 0 means an infinite window, so the action is taken when the total number of errors reaches the thresholdCount.  A thresholdCount of 0 means an infinite limit, errors are ignored.  A thresholdCount of 1 means that the first error triggers the action, hence the action must be taken when the threshold is REACHED, not exceeded as stated in the current docs.  (Although thresholds usually apply when exceeded, making the thresholdCount be the number permitted would require using a value such as -1 for no threshold, in contrast to our use of 0 to mean no timeout and no window)
> It should be an error to specify a (non-zero) thresholdWindow that is smaller than the thresholdCount ... an impossible situation.
> Note that if thresholdCount = 1 the thresholdWindow value is irrelevant, and if thresholdCount = thresholdWindow the action is taken when that many consecutive errors occur.

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