Perform multiple reads/searches with snapshot isolation / pausing tasks

[underflow00]

I sometimes want to perform multiple reads/searches with snapshot isolation (like in an SQL database), i.e. without seeing any changes to the documents made after the first read. It looks like this is not possible currently. Using locks/mutexes to block writes at the application/user level while the reads are also being performed also doesn't work, as the enqueued tasks are still running in the background.

Some form of SQL-like transactions or the ability to pause tasks would be helpful here.