update_chat_tags_by_id runs at the end of every completion when tag generation is enabled (the default). It loaded the full chat row including the multi-megabyte blob, mutated only meta.tags, committed, then refreshed the row, which re-fetched and re-parsed the entire blob a second time, and finally validated the whole thing into a ChatModel that its only caller (the auto-tagging handler) discards. add_chat_tag_by_id_and_user_id_and_tag_name had the same shape for a one-tag append, and orphan cleanup issued one COUNT query per removed tag.
Both tag writers now select only the meta column and issue a column-level UPDATE, never touching the blob; the single-tag path also skips the write entirely when the tag is already present. Orphan detection batches all per-tag counts into one round trip using one scalar subquery per tag with the exact same dialect-specific EXISTS filters as before; the existing single-tag count delegates to the batch helper so there is one implementation.
Benchmark (real SQLite DB, 200-message chat, ~600 KB blob):
| metric | before | after |
| --- | --- | --- |
| auto-tag update, 3 tags replaced | 12.85 ms | 7.36 ms |
The absolute saving grows with chat size since the blob no longer gets fetched, parsed, re-fetched and validated at all.
Functionally verified against a fresh database: tag replacement normalizes and filters the none placeholder, creates missing tag rows and leaves the blob untouched; orphaned tags are deleted while tags still referenced by other chats survive; single-tag add is idempotent; batch counts agree with the single count including unknown tags; unknown chat ids return None.
Both session factories run with expire_on_commit=False, so ORM objects keep their attribute values after commit. Every session.refresh issued right after a commit therefore re-SELECTed a row whose values the session already held, including full chat JSON blobs and user settings, purely to overwrite identical data. Fifty such calls existed across the model layer, covering nearly every write path in the app (chat inserts, title updates, pin/archive toggles, user role and settings updates, tool, prompt, function, model, file, tag, feedback, memory, automation and grant writes).
All fifty are removed. The only refreshes with an actual job were the two update-then-reload paths in tools and skills, where a Core UPDATE statement bypasses the identity map; those now use session.get(..., populate_existing=True), which guarantees a fresh row in one SELECT whether or not the row was already present in the session (the previous code issued get plus refresh, two SELECTs, on the default configuration).
Benchmark (real SQLite DB, per write):
| write path | before | after |
| --- | --- | --- |
| chat title update, ~600 KB chat blob | 2.08 ms | 1.24 ms |
| user role update, small row | 1.21 ms | 0.68 ms |
On Postgres each removed refresh is additionally a network round trip. The chat-blob case also skips re-parsing the entire JSON document per write.
Functionally verified against a fresh database: user insert, role and settings updates, chat insert (including the server-default meta column, which is always provided client-side), title update and pin toggle, tool insert and the Core-update reload path, tag insert and the prompt insert flow that pins version_id after history creation all return correct values and persist correctly.
insert_chat_files() stored any caller-supplied file_id with no ownership
check, so a user could attach another user's file to their own chat and
then read it through the shared-chat access path in has_access_to_file().
Filter file_ids to those the caller owns, is admin for, or can read.
Also repairs an UnboundLocalError introduced in 260ead64d: the existing
duplicate-check referenced `session` before it was assigned (db=session),
so the function threw on every call and no chat_file rows were persisted.
The bulk-clear-chat-tags endpoint's only frontend wrapper,
deleteTagsById in src/lib/apis/chats/index.ts, is dead: nothing imports
or calls it, the path is referenced nowhere else, and the route handler
has no internal caller. Removes the route handler, the dead wrapper, and
the now-orphaned Chats.delete_all_tags_by_id_and_user_id model method
(its sole caller was this route). The shared
Chats.delete_orphan_tags_for_user method is untouched.
Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Timothy Jaeryang Baek