♻️ Refactor task worker.

backend/resources/migrations/0015-improve-tasks-tables.sql

@@ -0,0 +1,29 @@
+DROP TABLE task;
+
+CREATE TABLE task (
+  id uuid DEFAULT uuid_generate_v4(),
+  created_at timestamptz NOT NULL DEFAULT clock_timestamp(),
+  modified_at timestamptz NOT NULL DEFAULT clock_timestamp(),
+  completed_at timestamptz NULL DEFAULT NULL,
+  scheduled_at timestamptz NOT NULL,
+  priority smallint DEFAULT 100,
+
+  queue text NOT NULL,
+
+  name text NOT NULL,
+  props jsonb NOT NULL,
+
+  error text NULL DEFAULT NULL,
+  retry_num smallint NOT NULL DEFAULT 0,
+  max_retries smallint NOT NULL DEFAULT 3,
+  status text NOT NULL DEFAULT 'new',
+
+  PRIMARY KEY (id, status)
+) PARTITION BY list(status);
+
+CREATE TABLE task_completed partition OF task FOR VALUES IN ('completed', 'failed');
+CREATE TABLE task_default partition OF task default;
+
+CREATE INDEX task__scheduled_at__queue__idx
+    ON task (scheduled_at, queue)
+ WHERE status = 'new' or status = 'retry';