Any error along the lines of "Streamed search execute failed ..." is a distributed search error. You'll find this error on the search head, however, it is pointing to some issue at the search peer. If you have multiple search peers, you'll need to investigate which peer triggered this error and then go deeper into why the error was triggered.
The St9bad_alloc might have something to do with a memory/resource issue at the search peer. Need more context.