Low available work.
For a couple of reasons, the result table has grown to the point where it no longer fits in main memory. That has been slowing the validators and assimilators, which is causing the result table to grow further.

We'd like to get it down to a manageable size before our Tuesday outage. To that end we are throttling work generation to a rate at which the table size is shrinking. We hope that this rate will increase as the table gets smaller.

So for the next few days work will be hard to come by (but not zero).

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