When set Query processors will ignore the 'data' section in snapshots, which is used for serving cached copies.
Can be set in: collection.cfg
Specifies if push collections running as query processors should download the document data from master. When set 'true' push query processors will not be able to server cached copies and will be unable to be promoted to Admin.
Defaults is to not ignore the document data, so cached copies are available on the query processor.
If you don't need cached copies of documents, and wish to save network load set: