Currently, locks are not held while time-series queries are parsed to replace the metaField with "meta" in write_commands.cpp and while retrieving the metaField in write_ops_exec.cpp. This may lead to concurrency issues where the collection may be dropped or replaced with another collection before the delete executes. To solve this, all the metaField related logic should be moved to the 
performSingleDeleteOp method in write_ops_exec.cpp.