How to troubleshoot my VBO operation which freezes at 50% every time? I have written custom code that creates a new action for Views Bulk Operations (VBO). I am trying to run the action and it gets stuck at "Prepared 46748 out of 46766".  If I run the same action with 25 or 100 records it works perfectly.  

Code has been changed but not that directly impacts this process. I do not know what code causes the regression and too many changes have been made to go back one commit at a time.  

There is nothing Watchdog related to this process.  

A little more on the custom action. The custom action adds the nid for each node to a queue to be processed fully over many cron jobs. I think the issue stems from the fact that every time a node is prepared by VBO it does a node save but I do not know what is happening to be sure.  

I am looking for advice on how to troubleshoot this scenario and find a solution.
Try to (temporary) increase the available memory with like 10 or 25%, and see if you get past that nr of 46748 (possibly even past 46766). If it doesn't help, it won't hurt ...

BTW, even though this question is not about using Rules in combination with VBO, you might want to also watch the video about "More details about VBO settings" (especially what is explained between (about 04:00 and 05:00). It provides some extra hints / tips to process like 100.000 nodes at once, which is quite a challenge to get to work (memory requirements, etc).