How to delete all revisions of given content type except the current revision? I am having a very large website which have around 400000 nodes of story content type. And these nodes have around 2000000 revisions. How can I delete all the revisions except the current revision so i can reduce the size of my database. 

I have tried node node revison delete module with no success. Page is getting time out.
The time out page is happening cause the modules is not using Drupal batch operation.

Did you try to use drush command that comes with the same module? you need to install Drush Help module to do so. If it didn't work, please post it here so I can provide you with a batch code.