Replace the per-row tree_modified_at bump triggers with AFTER ... FOR
EACH STATEMENT triggers using transition tables: each DML statement now
pays one bump covering the distinct ancestor chains of all affected
rows (locked in id order so concurrent bumps over overlapping chains
cannot deadlock), instead of one chain UPDATE per affected row.
Value-based change detection replaces UPDATE OF column lists (PG
forbids those with transition tables), so EXIF media_sort_date syncs
and no-op updates no longer bump at all, and file moves now invalidate
the source chain as well as the destination.
Also fix a latent bug surfaced while testing this: the descendant
path/lpath cascade (trg_folders_cascade_path) was declared AFTER
UPDATE OF path, lpath, but rename/move statements SET name/parent_id,
and BEFORE-trigger rewrites do not count for UPDATE OF — the cascade
never fired, leaving every descendant folder with a stale path/lpath
after any rename or move. The migration canonically repairs existing
trees and re-creates the cascade on the columns the app actually
writes.
delete_expired_bulk now deletes in LIMIT-ed batches (1000 files / 100
folders per round, each its own implicit transaction) ordered by
trashed_at and served by new partial indexes over trashed rows, so
retention purges no longer hold one unbounded transaction.
Verified against a local PG16 cluster: all migrations apply from
scratch, the new one re-runs idempotently, and a 16-case behavioral
battery passes (chain bumps for insert/update/delete/move/trash, EXIF
invisibility, no-op invisibility, cascade repair, FK-cascade depth
guards, batched purge shape and partial-index plan).
https://claude.ai/code/session_01QxwJDHqQhbMkHK333QtMme
Claude
4200209d4a