Edouard Vanbelle
1b9d9af5c0
on a file or folder change, the etag of each parent will be updated, this is O(n)
this is required to ensure NextCloud client will be aware of changes
In the future a Cursor will be better, this will be for OxiCloud-desktop
105 lines
4.0 KiB
PL/PgSQL
105 lines
4.0 KiB
PL/PgSQL
-- Folder rollup ETag: introduce `storage.folders.tree_modified_at`,
|
|
-- which is bumped whenever any descendant (file or folder) changes.
|
|
--
|
|
-- Motivation: WebDAV / NextCloud sync clients use a collection's ETag
|
|
-- to decide "did anything change inside this folder since I last
|
|
-- looked?". Until now `Folder::etag()` returned the folder UUID
|
|
-- (constant for the row's life), which made the answer always "no" —
|
|
-- forcing clients to do periodic deep PROPFIND walks to discover new
|
|
-- files. With this column, `Folder::etag()` becomes
|
|
-- `{id_short}-{tree_modified_at}` and clients can do O(changed)
|
|
-- recursion instead of O(tree).
|
|
--
|
|
-- The two triggers cascade an update timestamp up the ltree ancestor
|
|
-- chain on every file write and every folder mutation. Performance
|
|
-- ceiling: O(depth) row updates per mutation; deep concurrent writes
|
|
-- to the same root subtree can contend on the root row.
|
|
|
|
ALTER TABLE storage.folders
|
|
ADD COLUMN tree_modified_at TIMESTAMPTZ NOT NULL DEFAULT NOW();
|
|
|
|
-- Backfill existing rows: collapse the rollup timestamp to the
|
|
-- per-folder updated_at. Clients re-walking after deploy will see
|
|
-- one batch of "looks new to me" responses, which they handle as a
|
|
-- content-match-no-download — the expected one-time resync wave.
|
|
UPDATE storage.folders SET tree_modified_at = updated_at;
|
|
|
|
|
|
-- File-side trigger: any INSERT/UPDATE/DELETE on storage.files
|
|
-- bumps the file's parent folder + all its ancestors in the ltree.
|
|
-- Root-level files (folder_id IS NULL) have no ancestors and do not
|
|
-- trigger any folder bump — the root listing isn't an etag-emitting
|
|
-- collection in OxiCloud's model (no virtual root folder row).
|
|
CREATE OR REPLACE FUNCTION storage.bump_folder_tree_from_file()
|
|
RETURNS TRIGGER LANGUAGE plpgsql AS $$
|
|
DECLARE
|
|
target_folder_id UUID;
|
|
target_lpath ltree;
|
|
BEGIN
|
|
target_folder_id := COALESCE(NEW.folder_id, OLD.folder_id);
|
|
IF target_folder_id IS NULL THEN
|
|
RETURN COALESCE(NEW, OLD);
|
|
END IF;
|
|
|
|
SELECT lpath INTO target_lpath
|
|
FROM storage.folders
|
|
WHERE id = target_folder_id;
|
|
|
|
IF target_lpath IS NULL THEN
|
|
RETURN COALESCE(NEW, OLD);
|
|
END IF;
|
|
|
|
-- `lpath @> target_lpath` matches the target folder AND every
|
|
-- ancestor up to the root. The GiST index on lpath keeps this
|
|
-- to an index range scan even on deep trees.
|
|
UPDATE storage.folders
|
|
SET tree_modified_at = NOW()
|
|
WHERE lpath @> target_lpath;
|
|
|
|
RETURN COALESCE(NEW, OLD);
|
|
END;
|
|
$$;
|
|
|
|
CREATE TRIGGER files_bump_folder_tree_etag
|
|
AFTER INSERT OR UPDATE OR DELETE ON storage.files
|
|
FOR EACH ROW EXECUTE FUNCTION storage.bump_folder_tree_from_file();
|
|
|
|
|
|
-- Folder-side trigger: covers creates, deletes, renames, and moves.
|
|
-- A folder move changes its lpath — the OLD chain and NEW chain
|
|
-- both need bumping (old parents lost a child, new parents gained
|
|
-- one). Self-exclusion (id <> the changed row) avoids the row
|
|
-- bumping itself, which is meaningless and would amplify
|
|
-- contention on hot paths.
|
|
--
|
|
-- The `pg_trigger_depth() > 1` guard breaks recursion: when this
|
|
-- trigger UPDATEs ancestor rows below, those UPDATEs would fire
|
|
-- the same trigger again. Without the guard, a single child
|
|
-- creation would cascade an unbounded number of upward writes.
|
|
CREATE OR REPLACE FUNCTION storage.bump_folder_tree_from_folder()
|
|
RETURNS TRIGGER LANGUAGE plpgsql AS $$
|
|
BEGIN
|
|
IF pg_trigger_depth() > 1 THEN
|
|
RETURN COALESCE(NEW, OLD);
|
|
END IF;
|
|
|
|
IF TG_OP IN ('DELETE', 'UPDATE') AND OLD.lpath IS NOT NULL THEN
|
|
UPDATE storage.folders
|
|
SET tree_modified_at = NOW()
|
|
WHERE lpath @> OLD.lpath AND id <> OLD.id;
|
|
END IF;
|
|
|
|
IF TG_OP IN ('INSERT', 'UPDATE') AND NEW.lpath IS NOT NULL THEN
|
|
UPDATE storage.folders
|
|
SET tree_modified_at = NOW()
|
|
WHERE lpath @> NEW.lpath AND id <> NEW.id;
|
|
END IF;
|
|
|
|
RETURN COALESCE(NEW, OLD);
|
|
END;
|
|
$$;
|
|
|
|
CREATE TRIGGER folders_bump_folder_tree_etag
|
|
AFTER INSERT OR UPDATE OR DELETE ON storage.folders
|
|
FOR EACH ROW EXECUTE FUNCTION storage.bump_folder_tree_from_folder();
|