Currently, the primary of a three node PV1 replica set can spend 20% of its time iterating over items in the sleepersQueue. This has rendered PV1 unusable for the purposes of CSRS.

Most of the items in the sleepersQueue are cancelled callbacks concerning elections. Circumventing the problem, by scanning the queue from back to front on inserts, eliminates the performance impact of this, but is not a suitable solution as it does not alleviate the memory overhead.