Files
EventSnap/backend/migrations/023_derivative_attempts.up.sql
MechaCat02 e1c689d1a7 chore(migrations): renumber 021-023 to 023-025 to clear the collision with main
main independently shipped 021_hashtag_counts_respect_bans and
022_client_upload_idempotency. sqlx::migrate! embeds ./migrations and refuses two
files per version, so these three had to move before the branch could merge at all.

Contents are untouched — only the version prefixes change. Renumbering (rather than
renumbering main's) is the safe direction: main is already deployed, so its 021 and
022 are applied in production and their versions are now immutable.
2026-08-08 21:04:58 +02:00

24 lines
1.5 KiB
SQL

-- Bound how many times a permanently-failing upload can be re-processed.
--
-- Without this, one poisoned row is an outage. The upload row is committed BEFORE compression
-- starts, `derivatives_rev` defaults to 0, and `set_derivatives_rev` only runs on success — so
-- a row whose processing kills the container survives at rev 0, the unconditional startup
-- backfill re-selects it on the next boot, and `restart: unless-stopped` turns that into an
-- infinite kill loop. Every restart also drops every SSE stream and truncates every in-flight
-- upload. That was reachable via a single large PNG (see services/compression.rs), but the
-- shape is general: any input that can kill or hang the worker repeats forever.
--
-- The counter is incremented WRITE-AHEAD, before the work is attempted, because the failure
-- mode being defended against is a SIGKILL — no error is returned, no handler runs, no Drop
-- fires. A counter bumped in an error path increments zero times per crash and changes nothing.
ALTER TABLE upload ADD COLUMN IF NOT EXISTS derivative_attempts SMALLINT NOT NULL DEFAULT 0;
-- Last failure text, so a row that has given up can be diagnosed without reproducing it.
-- Nothing reads this in code; it exists for the operator.
ALTER TABLE upload ADD COLUMN IF NOT EXISTS derivative_last_error TEXT;
-- Serves the backfill selection, which now filters on both columns.
CREATE INDEX IF NOT EXISTS idx_upload_derivative_backfill
ON upload (derivatives_rev, derivative_attempts)
WHERE deleted_at IS NULL;