The prefetcher fetched capture ranges into the corpus 16 at a time in id order, and ids run group by group: the 16 were one or two groups', the per-group connection limit (4) let 4-8 loops work and left the rest idle, ~30k articles/s for the first batch of 19,955 capture ranges. Now at most perGroup / perRange (2) of a group are taken, so the 16 come from 8+ groups and every loop gets work (and the pool asks for more). Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>