perf(mobile): memoize npub labels by brow · Pull Request #9137 · block/buzz

brow · 2026-11-05T20:52:10Z

Opening a big channel on mobile stalls while member labels resolve. On an iPhone 12 mini (wired Profile build of main 120d75d), opening a 5,892-member channel had frames of 217, 113 and 101 ms. The channel identity scope recomputed 13 times during the open as profiles arrived, 25 to 35 ms each: 235 ms of 1,755 ms UI CPU, 190 ms of it bech32 encoding. Every recompute labels each member without a profile name by npub (missingOwnerProfiles → IdentityNameSources.factFor → shortPubkey → fullNpub), and encoded the same keys again. The same chain cost 152 ms in a 15 s resume with the channel open.

fullNpub now memoizes encodings by hex key, bounded at 8,192 entries. Once full it keeps what it has, so a roster larger than the limit still reuses most of its encodings. Labels are unchanged.

Validation

Added tests: fullNpub reuses the encoding of a key it has already encoded fails without the memo; a roster larger than the cache still reuses its encodings fails if the cache clears when full.
Host benchmark, shortPubkey over 5,900 random keys: 53.5 ms on the first pass, about 3.1 ms on later passes.
Full mobile suite passes except the 10 known notification/push failures and push_lease_revocation_outbox_test, which also fail on main. Analyze clean.
Automated simulator run of this branch (debug build, Builderlab community): searched "studio", opened a channel result and came back; people results show the same short npub labels as main (for example npub194z...aq3k).
No post-change device capture. The scope still recomputes as profiles arrive; this removes the encoding cost from each recompute.

🤖 Generated with Claude Code

Identity views label every roster member without a profile name by npub on each rebuild. On a 5.9k-member channel that bech32 work dominated 13 scope recomputes while opening it. Keep a bounded hex-to-npub map. Co-authored-by: studio <dc2fc481343672df31a689840c09299972e704dac592e0da6f18486646a7ee3e@buzz.block.builderlab.xyz> Signed-off-by: Tom Brow <tomb@squareup.com>

chatgpt-codex-connector · 2026-11-05T20:56:49Z

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-11-05T20:59:29.604300Z	`5d2ce12`	Draft marked ready

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github-actions · 2026-11-05T20:58:08Z

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Exact PR diff: 74abe2f0fe1a5341c8c7637b79569dd59176be27...14d93fca745c893cf483751a3db1c9c76b5483a1

Model: gpt-6.1-sol

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Overall Risk: NONE

No concrete findings in the authorized PR range. The bounded cache preserves public-key validation and canonical encoding, and stores no community-specific data.

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No concrete security, correctness, or reliability findings were identified.

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Review used read-only source, caller, test, and history inspection. Builds and tests were not executed, as requested.

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Reviewed commit: 5d2ce12d0d

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chatgpt-codex-connector · 2026-11-05T20:59:26Z

+String _encodeNpub(String hexPubkey) {
+  final cached = _npubs[hexPubkey];
+  if (cached != null) return cached;
+  if (_npubs.length >= _npubLimit) _npubs.clear();


Avoid clearing the entire npub cache at capacity

When a channel still has more than 8,192 unnamed members, clearing the entire map causes repeated same-order roster scans to thrash instead of being memoized. For example, an 8,193-key scan ends with only the last key cached; the next scan fills the map with that tail entry plus the first 8,191 keys, clears it before reaching the cached tail, and therefore re-encodes every key again. Larger communities can consequently retain the UI-isolate stalls this change is intended to remove; use a bounded policy that preserves useful entries across over-capacity scans and cover a roster just above the limit.

AGENTS.md reference: AGENTS.md:L23-L30

Useful? React with 👍 / 👎.

Clearing at the limit re-encoded every key of a larger roster on each scan. Co-authored-by: studio <dc2fc481343672df31a689840c09299972e704dac592e0da6f18486646a7ee3e@buzz.block.builderlab.xyz> Signed-off-by: Tom Brow <tomb@squareup.com>

wesbillman

No blockers. The memo is keyed on the normalized lowercase hex, only stores validated keys, is bounded, and labels are unchanged; the tests cover reuse and the full-cache case. CI is green.

Carl, an automated reviewer, commenting via Wes's GitHub account.

* origin/main: (60 commits) feat(cli): user status expiry and status read (#8777) feat(cli): send a thread message to the channel (#8778) feat(relay): add kind 30180 custom emoji entry (#8783) feat(cli): read-only unread state (NIP-RS) (#8789) feat(cli): report a message to relay moderators (#8829) buzz-db: read explicit #h sets one channel at a time (#9110) feat(cli): list huddles and their participants (#8830) docs(agents): add open-source boundary and drop private repo list (#9114) fix(mobile): answer push snapshot bridge calls at user-initiated QoS; report hop latency on callback timeout (#8916) test(mobile): lock in invite-page and bare-host community link entry (#9047) fix(desktop): keep an own send out of the frozen timeline tail (#9095) fix(db): end each table's maintenance transaction before the next (#9096) perf(mobile): show a static placeholder for posterless videos (#9138) fix(desktop): compensate head trims from the unclamped scroll offset (#9094) fix(relay): read kind:39000/39001 inputs behind the replacement lock (#9035) fix(db): unlock the storage-accounting lease before its session closes (#9097) test(relay,db): remove three timing races from Postgres and E2E tests (#9098) fix(db): keep busy-reader history reads off the writer and cap them per pod (#9132) perf(mobile): memoize npub labels (#9137) mobile: stop re-parsing messages on every resume (#9140) ... Co-authored-by: Duncan <dcfd242e557282d7a1e2cf2e6877522682f1e5c6156dc92ca7d90eaedd3b0f95@buzz.block.builderlab.xyz> Signed-off-by: Will Pfleger <wpfleger@block.xyz> # Conflicts: # crates/buzz-cli/src/commands/users.rs

brow marked this pull request as ready for review November 5, 2026 20:56

brow requested a review from a team as a code owner November 5, 2026 20:56

brow temporarily deployed to codex-review November 5, 2026 20:56 — with GitHub Actions Inactive

github-actions Bot added the codex-security-review-current The posted Codex security review matches its recorded range. label Nov 5, 2026

chatgpt-codex-connector Bot reviewed Nov 5, 2026

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mobile: keep npub cache entries once full

14d93fc

Clearing at the limit re-encoded every key of a larger roster on each scan. Co-authored-by: studio <dc2fc481343672df31a689840c09299972e704dac592e0da6f18486646a7ee3e@buzz.block.builderlab.xyz> Signed-off-by: Tom Brow <tomb@squareup.com>

brow temporarily deployed to codex-review November 5, 2026 21:12 — with GitHub Actions Inactive

github-actions Bot added codex-security-review-current The posted Codex security review matches its recorded range. and removed codex-security-review-current The posted Codex security review matches its recorded range. labels Nov 5, 2026

wesbillman reviewed Nov 5, 2026

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wesbillman approved these changes Nov 5, 2026

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brow merged commit 7ac16b2 into main Nov 5, 2026
53 checks passed

brow deleted the tomb/mobile-memo-npub-labels branch November 5, 2026 21:49

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perf(mobile): memoize npub labels - #9137

perf(mobile): memoize npub labels#9137
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