This ticket is in reference to how at present BatchWriteExec and BulkWriteExec will always process an update op in a batch by itself when the update op’s filter doesn’t include the shard key or _id, which is likely suboptimal. Here is a link to the relevant code.

The goal of this ticket is to investigate if we can do better than this without incurring unacceptable downsides.(Batching in this scenario could maybe potentially increase the rate of write conflicts for some workloads, so we need to understand any such tradeoffs in order to decide how to best proceed.)