How Do I: Recycle $db->fetch_array($qry) ?

[DigitalCrowd]

Okay... I'm drawing a blank.

I do a query... example:

$qry=$db->query_read("SELECT field1,field2,field3 from vb_xyz WHERE field4='myvalue' and field8='Not_Processed'");

// SET FIELD8 TO PENDING TO STOP OVERLAPPING CRONS

while ($result=$db->fetch_array($qry)) {

    $db->query_write("UPDATE vb_xyz SET field8='Pending' WHERE field1='$result[field1]'");

}

// BEGIN PERFORMING ACTIONS, UPDATE DB FOR EACH FIELD ONCE COMPLETE

while ($result2=$db->fetch_array($qry)) {

    // action code here
    // this is what is not working, "$qry" seems to be "empty" or "finished"

}

So, my hang up (and maybe someone can suggest a better way to do this) is with this second "while" loop. I want to keep overlapping cron runs (example, running every minute, but one cron launch script lasts longer than 1 minute) from duplicating efforts.

In the first loop, I update a given field to "Pending" status and in the second loop, I actually take action. I can't do this with one loop because I want to make sure that the Pending status is applied to the entire selected $qry before running a process, so no future spawned scripts duplicate what a previously spawned script is already attempting to complete.

I know in PHP you can take an array and set the counter back to 0. But, how do I do this with the mysql query and the while clause using fetch_array?

If you know of a better way to do what I want to do, Im open for suggestions.

Thanks!

PS - Above code is for example purposes only and not copied from my actual working code.