CFThread Corruption Issue

I've recently starting using cfthread on one of my CF 9 servers.   I've seen some wildly odd behaviour from the threads and am wondering if this is a known issue.

I am grabbing a set of data which is 1200 rows deep.  I loop over that data 12 times, grab 100 rows each time and create a unique thread.   If I don't artificially add delay the query distribution between the threads is random and weighted heavily towards the last thread created.   Even after adding 5-6 seconds of delay between spawning new threads – the distribution is not level.   The ONLY time I can get 100 rows per thread is when I insert a cfdump of the query (adding a LOT of additional processing time).

Im writing the thread names into my table for debug purposes - so I can get an exact count of which thread is processing which numbers.

Here is the distribution after adding 5-6 seconds of delay for a set of 100:

threadtest COUNT(`threadtest`)

MigThread1 21

MigThread2 51

MigThread3 28

-- as you can see, though the data set passed into each thread is distinct, is seems to be handed to the threads in a random way -- as if the thread attributes and scopes were immediately corrupted.   Oddly, I always get the number of rows processed that I want - just not distributed between the threads as I expect.

Here is the code:

<!---get the data --->

<cfquery name="getTNs" datasource="xxxx">

                SELECT SubKey, TN, LRN, MAC, CLLI, StagingFallout, FinalFallout

    FROM MigValidationNew

    WHERE JobKey = '#JobKey#' AND StagingFallout <> '1'

</cfquery>

<!--- Build a new dataset so the threads are better controlled --->

<cfset SortedTNs = querynew("IndexCounter, TN, SubKey")>

                <cfset RowCounter = '1'>

                <cfoutput query="getTNs">

                <cfset QueryAddRow(SortedTNs)>

                                 <cfset QuerySetCell(SortedTNs,"IndexCounter",#RowCounter#)>

                                <cfset QuerySetCell(SortedTNs,"TN",#TN#)>

                                <cfset QuerySetCell(SortedTNs,"SubKey",#SubKey#)>

                                <cfset RowCounter = #RowCounter# + 1>

                </cfoutput>

<!--- Set the number of threads by dividing the total TNs returned by n --->

<cfset numGroups = 50>

<cfset MigrationRounds = Ceiling(RowCounter / numGroups )>

<!--- Loop over the record set, creating n threads each with n TNs --->

<cfloop index="loopindex" from="1" to="#MigrationRounds#">

<!--- Ensure a unique thread name --->

                <cfset threadName = "MigThread#loopindex#">

                <cfif #loopindex# EQ 1>

                                <cfset startNumber = #loopindex#>

                <cfelse>

                                <cfset startNumber = ((#loopindex# - 1) * numGroups) + 1>

                </cfif>

                <cfset endNumber = #loopindex# * numGroups>

                                <cfquery name="getSubset" dbtype="query">

                SELECT IndexCounter, TN, SubKey

        FROM SortedTNs

        WHERE IndexCounter >= #startNumber# AND IndexCounter <= #endNumber#

                </cfquery>

<cfoutput><p>#threadName# St: #startNumber#  En: #endNumber# RecordCount is #getSubset.RecordCount#</p></cfoutput>       

                <cfthread

        name="#threadName#"

        action="run"

        priority="HIGH">

                                <cfoutput query="getSubset">

            <!--- Update the database with the thread name--->

            <cfquery name="updateTN" datasource="xxx">

                Update MigValidationNew

                SET threadtest = '#threadName#'

                WHERE SubKey = '#SubKey#'

            </cfquery>

                </cfoutput>

</cfthread>

<!--- Add delay between the threads to limit the corruption--->

<cfloop index="InternalIdx" from="1" to="3000000" step="1"> </cfloop>

<p>Next Thread!</p>

</cfloop>

<!--- Rejoin the threads for the display --->

<cfthread action="join" timeout="299999"/>