This came out of WT-8880. The fields in conn->capacity could be read by another thread at any time, which is possibly an issue if we're in the middle of __capacity_config and we're halfway through setting various fields.

To be clear, I'm not sure this is guaranteed to be a problem - it might be that a torn write to the various capacities/thresholds is OK because they're used in a certain way (e.g. only on startup). That said, these three lines seem a bit suspect:

cap->threshold = ((cap->ckpt + cap->evict + cap->log) / 100) * WT_CAPACITY_PCT;
if (cap->threshold < WT_CAPACITY_MIN_THRESHOLD)
    cap->threshold = WT_CAPACITY_MIN_THRESHOLD;

The scope of the ticket is to (1) identify whether this is a real problem and (2) fix it.