perf(api): simplify hourly balance history query

api/v1_users_balance_history.go

@@ -96,44 +96,47 @@ func (app *ApiServer) v1UsersBalanceHistory(c *fiber.Ctx) error {
 		return err
 	}
 
-	// Build SQL query with granularity parameter.
 	// First sum balance_usd across mints at each hourly snapshot to get the
-	// total portfolio value per hour. For 'daily', pick the latest hour within
-	// each day (end-of-day balance) — do NOT sum balances across hours, since
-	// each hour is a point-in-time snapshot, not an additive quantity.
+	// total portfolio value per hour.
 	sql := `
-		WITH hourly_totals AS (
-			SELECT
-				timestamp,
-				SUM(balance_usd) AS balance_usd
-			FROM user_balance_history
-			WHERE user_id = @user_id
-				AND timestamp >= @start_time
-				AND timestamp <= @end_time
-			GROUP BY timestamp
-		),
-		bucketed AS (
-			SELECT
-				CASE
-					WHEN @granularity::text = 'daily' THEN date_trunc('day', timestamp)
-					ELSE timestamp
-				END AS bucket_timestamp,
-				timestamp AS source_timestamp,
+		SELECT
+			timestamp,
+			SUM(balance_usd) AS balance_usd
+		FROM user_balance_history
+		WHERE user_id = @user_id
+			AND timestamp >= @start_time
+			AND timestamp <= @end_time
+		GROUP BY timestamp
+		ORDER BY timestamp ASC
+	`
+
+	if params.Granularity == GranularityDaily {
+		// For daily, pick the latest hour within each day (end-of-day balance).
+		// Do not sum balances across hours, since each hour is a point-in-time
+		// snapshot, not an additive quantity.
+		sql = `
+			WITH hourly_totals AS (
+				SELECT
+					timestamp,
+					SUM(balance_usd) AS balance_usd
+				FROM user_balance_history
+				WHERE user_id = @user_id
+					AND timestamp >= @start_time
+					AND timestamp <= @end_time
+				GROUP BY timestamp
+			)
+			SELECT DISTINCT ON (date_trunc('day', timestamp))
+				date_trunc('day', timestamp) AS timestamp,
 				balance_usd
 			FROM hourly_totals
-		)
-		SELECT DISTINCT ON (bucket_timestamp)
-			bucket_timestamp AS timestamp,
-			balance_usd
-		FROM bucketed
-		ORDER BY bucket_timestamp ASC, source_timestamp DESC
-	`
+			ORDER BY date_trunc('day', hourly_totals.timestamp) ASC, hourly_totals.timestamp DESC
+		`
+	}
 
 	rows, err := app.pool.Query(c.Context(), sql, pgx.NamedArgs{
-		"user_id":     userId,
-		"start_time":  startTime,
-		"end_time":    endTime,
-		"granularity": string(params.Granularity),
+		"user_id":    userId,
+		"start_time": startTime,
+		"end_time":   endTime,
 	})
 	if err != nil {
 		return err