I’m running a free tier Atlas 5.0.9 replica set cluster and I used to be able to query the collections using op_query with no filter. As of a few days ago, attempting this returns no records(I can see the empty results returned in the network trace). If I add a simple filter to the op_query request then rows are returned. Did something change in Atlas recently?
I know op_query is deprecated and I am planning to switch to op_msg, but was there some change on the Atlas server which caused this change in behavior?
Hi @Brian_Derwart welcome to the community!
Since op_query is deprecated and will be removed in future MongoDB version, I think this is an excellent time for you to update the code you have 
Did something change in Atlas recently?
Yes Atlas is constantly evolving and changing, although what exactly changed in the op_query front, I’m not really sure. My suggestion is it’s best to move to op_msg sooner rather than later since this will be the supported one moving forward, and will avoid any future issues with using op_query.
Best regards
Kevin