Sync unchecked headers for price feeds

- Indicate that a header has been checked for logs if no logs returned
- Indicate that a header has been checked for logs when persisting a log
- Fetch headers that need to be checked based on absence of the above

db/migrations/1536785159_create_checked_headers_table.down.sql

@@ -0,0 +1 @@
+DROP TABLE public.checked_headers;

db/migrations/1536785159_create_checked_headers_table.up.sql

@@ -0,0 +1,5 @@
+CREATE TABLE public.checked_headers (
+  id                  SERIAL PRIMARY KEY,
+  header_id           INTEGER UNIQUE NOT NULL REFERENCES headers (id) ON DELETE CASCADE,
+  price_feeds_checked BOOLEAN NOT NULL DEFAULT FALSE
+);

db/schema.sql

@@ -662,6 +662,37 @@ CREATE SEQUENCE public.blocks_id_seq
 ALTER SEQUENCE public.blocks_id_seq OWNED BY public.blocks.id;
 
 
+--
+-- Name: checked_headers; Type: TABLE; Schema: public; Owner: -
+--
+
+CREATE TABLE public.checked_headers (
+    id integer NOT NULL,
+    header_id integer NOT NULL,
+    price_feeds_checked boolean DEFAULT false NOT NULL
+);
+
+
+--
+-- Name: checked_headers_id_seq; Type: SEQUENCE; Schema: public; Owner: -
+--
+
+CREATE SEQUENCE public.checked_headers_id_seq
+    AS integer
+    START WITH 1
+    INCREMENT BY 1
+    NO MINVALUE
+    NO MAXVALUE
+    CACHE 1;
+
+
+--
+-- Name: checked_headers_id_seq; Type: SEQUENCE OWNED BY; Schema: public; Owner: -
+--
+
+ALTER SEQUENCE public.checked_headers_id_seq OWNED BY public.checked_headers.id;
+
+
 --
 -- Name: eth_nodes; Type: TABLE; Schema: public; Owner: -
 --
@@ -1071,6 +1102,13 @@ ALTER TABLE ONLY maker.vat_init ALTER COLUMN id SET DEFAULT nextval('maker.vat_i
 ALTER TABLE ONLY public.blocks ALTER COLUMN id SET DEFAULT nextval('public.blocks_id_seq'::regclass);
 
 
+--
+-- Name: checked_headers id; Type: DEFAULT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public.checked_headers ALTER COLUMN id SET DEFAULT nextval('public.checked_headers_id_seq'::regclass);
+
+
 --
 -- Name: eth_nodes id; Type: DEFAULT; Schema: public; Owner: -
 --
@@ -1375,6 +1413,22 @@ ALTER TABLE ONLY public.blocks
     ADD CONSTRAINT blocks_pkey PRIMARY KEY (id);
 
 
+--
+-- Name: checked_headers checked_headers_header_id_key; Type: CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public.checked_headers
+    ADD CONSTRAINT checked_headers_header_id_key UNIQUE (header_id);
+
+
+--
+-- Name: checked_headers checked_headers_pkey; Type: CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public.checked_headers
+    ADD CONSTRAINT checked_headers_pkey PRIMARY KEY (id);
+
+
 --
 -- Name: watched_contracts contract_hash_uc; Type: CONSTRAINT; Schema: public; Owner: -
 --
@@ -1649,6 +1703,14 @@ ALTER TABLE ONLY public.token_supply
     ADD CONSTRAINT blocks_fk FOREIGN KEY (block_id) REFERENCES public.blocks(id) ON DELETE CASCADE;
 
 
+--
+-- Name: checked_headers checked_headers_header_id_fkey; Type: FK CONSTRAINT; Schema: public; Owner: -
+--
+
+ALTER TABLE ONLY public.checked_headers
+    ADD CONSTRAINT checked_headers_header_id_fkey FOREIGN KEY (header_id) REFERENCES public.headers(id) ON DELETE CASCADE;
+
+
 --
 -- Name: headers eth_nodes_fk; Type: FK CONSTRAINT; Schema: public; Owner: -
 --