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Verified names are read in subscriptions of up to 128 people. Each time
someone new was tracked, the batches were rebuilt from the whole tracked
list, so the last partial batch got a new identity, was closed, and was
reopened with everyone in it plus the newcomer. Profiles show up a few
at a time (search results, channel members, mentions), so the same
records were read again and again. Past 1,024 tracked people, each
newcomer evicts the oldest, which shifts every batch boundary, so every
batch was closed and all 1,024 records were read again.
Now an open batch stays open as long as all its people are still
tracked. Newly tracked people get a batch of their own. A batch that
loses someone to eviction, or that the relay retried, is replaced as
before, and so is a batch whose person was evicted and tracked again
before the batch was re-checked, so their check mark and cached name are
re-read. Once four batches are smaller than 128, the next addition
merges the smallest of them with the newcomers until they fill a batch
(at least one, so no fifth small batch appears). The subscription count
stays within four of the minimum, and a merge re-reads at most 128 plus
the largest small batch.
People already checked also stay checked while a newcomer's batch opens;
before, the reopened batch briefly unchecked them.
### Validation
New tests: tracking one more person opens a batch with only that person,
and the people already checked stay checked throughout; with four small
batches of 64 open, one more person merges two of them into a full batch
and leaves the other two open; a large addition past four small batches
still retires one; tracking one more person at the 1,024 limit re-reads
only the batch that lost the oldest person; a person evicted and tracked
again before the sync is re-read and checked; and a re-tracked person
keeps their verified name when the cached-name limit trims it. Existing
batch, eviction, retry and reconnect tests pass unchanged (one comment
updated). Full mobile test suite and `flutter analyze` pass.
On an iPhone 12 mini signed in to Block's Builderlab (instrumented
profile build of e2fb02c), opening search and typing "presence" after
opening a channel and a thread: verified-name reads went from 21
subscriptions and 328 KB before this change to 11 and 88 KB with it
(counted per subscription opened; the first revision measured the same
way gave 11 and 90 KB).
The same automated run covered cold start, opening the-squad and one of
its threads, search with the People filter, opening buzz-mobile's
details and scrolling its full 86-person member list, and a 60 s
background then resume (the resync re-read 2 batches, 65 KB). Names
rendered throughout.
### Regressions
Up to four more open subscriptions while small batches accumulate, each
held open by the relay like the existing ones. A community with under
128 tracked people now has up to five instead of one. No merge policy
reads less than the old slicing on every sequence of additions. In a
model of 3,000 random tracking sequences, this one read more records
than the old code in about 1 sequence in 500, by at most a quarter.
---------
Signed-off-by: Tom Brow <tomb@squareup.com>
Co-authored-by: Tom Brow <tomb@squareup.com>
Co-authored-by: studio <dc2fc481343672df31a689840c09299972e704dac592e0da6f18486646a7ee3e@buzz.block.builderlab.xyz>
Co-authored-by: studio <dc2fc481343672df31a689840c09299972e704dac592e0da6f18486646a7ee3e@localhost>