SERVER-88298 turned on the QueryMemoryTracking feature flag on by default. That means that now by default we will include new metrics in

• Slow query log lines
• $currentOp output
• explain(executionStats)
• Database profiler output in system.profiles

Each of these will be updated to include a new field peakTrackedMemUsage. This field may be reported on the query as a whole (summing up all the stages that track memory) and for individual stages themselves, if they have been instrumented with memory tracking.

In addition, the $currentOp stage will also include a new field inUseTrackedMemBytes, which reports the amount of tracked memory currently in use for either idle or active cursors.

Description of Linked Ticket

Enable the feature flag for this project.

SPM-3716 just added maxUsedMemBytes to explain output if the query memory tracking feature flag is on, but there is already a field in the for some stages' explain that represents the same value ("maxTotalMemoryUsage"). It doesn't make sense to output both and now that the feature flag will be enabled, we should only output the field from this project ("peakTrackedMemBytes")

We should also audit the other memory-tracked stages to see if this is a problem for other stages.