Simplify-pass folds on the #23254 salvage:
- REUSE (HIGH): append_messages_batch now delegates row serialization to
the pre-existing _insert_message_rows helper (already shared by
replace_messages / archive_and_compact / portability import) instead
of adding a third serialization path (_prepare_message_row +
_MESSAGE_INSERT_SQL are gone). One row-writer for every multi-row
path; the row-ID return was consumed by no production caller, so the
batch returns the inserted count.
- QUALITY (HIGH): the compression-lock + compression-closed admission
guards are extracted into _check_transcript_write_guards, shared by
append_message and append_messages_batch (previously duplicated 23
lines that had already needed targeted fixes, #74478). The role-gated
reasoning filtering is no longer duplicated in run_agent.py — it
lives at its one site inside _insert_message_rows.
- EFFICIENCY (MEDIUM, measured): unbounded seed copies hold one BEGIN
IMMEDIATE for seconds (10k rows ~= 2.4s; FTS triggers dominate) and
monopolize the in-process write lock. append_messages_batch grows a
chunk_rows param; all seed/copy call sites use chunk_rows=500. Same
recovery semantics as the old per-row loops, bounded lock holds.
- REUSE (MEDIUM): the two remaining per-row branch-copy loops found by
the pass (gateway/slash_commands.py /branch, hermes_cli
cli_commands_mixin.py branch) are converted to chunked batches too
(AsyncSessionDB's generic to_thread forwarder covers the async site).
Turn-flush benchmark unchanged after the refactor: 2.43 -> 0.87 ms
median per 5-message flush (64% faster).
Re-derivation of #23254 (@devsart95) on today's flush loop. The turn
flush in _flush_messages_to_session_db wrote one BEGIN IMMEDIATE
transaction per message row; a typical agent turn (user + assistant +
tool results) paid 3-8 transactions -- and, off WAL (the default on
macOS while the WAL-reset guard is active), 3-8 fsyncs -- per turn.
Adds SessionDB.append_messages_batch: same row shape as append_message
(shared _prepare_message_row serializer + _MESSAGE_INSERT_SQL column
list, so the two writers cannot drift), same compression-lock and
compression-closed guards, one aggregated session-counter UPDATE, one
transaction for the whole batch. Row serialization stays outside the
write lock.
The flush loop now collects the turn's new rows and writes them in one
call. All-or-nothing pairs exactly with the persisted-marker stamping:
on failure no rows landed and no markers were stamped, so the next
flush re-writes the whole tail (same recovery contract as before,
minus the partial-prefix case that could double-count).
Measured (same harness, 5-message turn, journal_mode=DELETE,
synchronous=FULL): 2.32ms -> 0.83ms median per turn flush (64% faster,
5 fsyncs -> 1). On WAL the win is smaller but the atomicity fix holds.
kshitij
devsart95