Optimise the ranking queries by using distinct instead of join and index on blocknum

Author: harsh-98

migrations/000002_pool.up.sql

@@ -8,7 +8,7 @@ CREATE TABLE pools (
 );
 
 CREATE TABLE pool_stats (
-    id SERIAL PRIMARY KEY,
+    id SERIAL NOT NULL,
     pool varchar(42),
     block_num integer,
     unique_users integer,
@@ -40,7 +40,7 @@ ALTER TABLE ONLY pool_stats
 
 
 CREATE TABLE pool_ledger (
-    id SERIAL PRIMARY KEY,
+    id SERIAL NOT NULL,
     block_num integer,
     log_id integer,
     pool character varying(42),

migrations/000008_debts.up.sql

@@ -3,7 +3,7 @@ CREATE TABLE debt_sync (
 );
 
 CREATE TABLE debts (
-    id SERIAL PRIMARY KEY,
+    id SERIAL NOT NULL,
     block_num integer,
     session_id character varying(100),
     cal_health_factor varchar(80),

migrations/000016_rankings.up.sql

@@ -27,24 +27,20 @@ language plpgsql
 as $$
 DECLARE
 BEGIN
-    RETURN QUERY WITH common AS 
-		(SELECT min(d1.block_num) , max(d1.block_num) , d1.session_id from debts d1
-			JOIN (SELECT * FROM blocks WHERE timestamp > (extract(epoch from now())::bigint - $1)) b 
-			ON b.id = d1.block_num group by d1.session_id)
-		SELECT *, (t2.new_profit-t1.old_profit) profit_usd, t1.old_collateral collateral_usd,
+    RETURN QUERY SELECT *, (t2.new_profit-t1.old_profit) profit_usd, t1.old_collateral collateral_usd,
 		(t2.new_profit_underlying-t1.old_profit_underlying) profit_underlying, t1.old_collateral_underlying collateral_underlying,
 			(t2.new_profit-t1.old_profit)/(t1.old_collateral) roi  FROM
-		(SELECT 
-			d.collateral_usd old_collateral, d.profit_usd as old_profit, d.total_value_usd old_total,
+        (SELECT distinct on (d.session_id) d.collateral_usd old_collateral, d.profit_usd as old_profit, d.total_value_usd old_total,
 			d.collateral_underlying old_collateral_underlying, d.profit_underlying as old_profit_underlying,
-			d.session_id sid
-			FROM debts d JOIN common ON common.min = d.block_num AND d.session_id=common.session_id) t1
-		JOIN (SELECT 
-			d.collateral_usd new_collateral, d.profit_usd as new_profit, d.total_value_usd new_total,
+            d.session_id sid
+			FROM debts d WHERE block_num >= (SELECT min(id) FROM blocks WHERE timestamp > (extract(epoch from now())::bigint - $1)) 
+            order by d.session_id, block_num) t1
+        JOIN (SELECT distinct on (d.session_id) d.collateral_usd new_collateral, d.profit_usd as new_profit, d.total_value_usd new_total,
 			d.collateral_underlying new_collateral_underlying, d.profit_underlying as new_profit_underlying,
-			d.session_id, common.max current_block
-			FROM debts d JOIN common ON common.max = d.block_num AND d.session_id=common.session_id) t2 
-		ON t1.sid = t2.session_id;
+			d.session_id, block_num current_block
+			FROM debts d WHERE block_num >= (SELECT min(id) FROM blocks WHERE timestamp > (extract(epoch from now())::bigint - $1)) 
+            order by d.session_id, block_num DESC) t2
+            ON t1.sid = t2.session_id;
 END $$;
 
 CREATE  MATERIALIZED VIEW ranking_7d AS