Does a SELECT happen all at once, or progressively
I have a process which finds a list of files to be deleted using a SELECT `where `delete` = 'Y'`.

I set this process running the other day but it takes a while because it actually does the file deletions too.

And in the middle of its long operation, I was using the application and deleted one more file.

At this point I realised I didn't know if that file would be deleted, because I didn't know if the SELECT would have found all the files at the start, or if it was finding them progressively and would get to my newly-deleted file eventually.

Does a SELECT happen all at once, or progressively
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I have a process which finds a list of files to be deleted using a SELECT `where `delete` = 'Y'`.

I set this process running the other day but it takes a while because it actually does the file deletions too.

And in the middle of its long operation, I was using the application and deleted one more file.

At this point I realised I didn't know if that file would be deleted, because I didn't know if the SELECT would have found all the files at the start, or if it was finding them progressively and would get to my newly-deleted file eventually.
