Update readme

Author: thomas-kl1

README.md

@@ -57,7 +57,17 @@ There is also a few method that refers to this attribute, such as:
 - \Magento\Catalog\Model\ResourceModel\Product\Collection::joinMinimalPrice (Never called)
 
 This attribute and methods are not used in the Commerce edition neither.  
-This module updates and reuse this existing attribute in order to give it a true usage.
+This module updates and reuse this existing attribute in order to give it a true usage.  
+
+Also, while investigating a bug where the minimal price value was not handled in the PDP nor PLP.
+It seems that the catalog_product_index_price is not used to render and display the final prices.  
+When inspecting the query logs, it seems that even if the indexer is loaded and applied to the product list, 
+when the template render the prices, the following method is used `\Magento\Catalog\Block\Product\ListProduct::getProductPrice`.
+This method calls `Magento\Framework\Pricing\Render::render` which render a price by code. The engine will proceed with 
+`Magento\Catalog\Pricing\Price\FinalPrice` and `Magento\Catalog\Pricing\Price\BasePrice`. The rendering is finally delegated 
+to `Magento\CatalogRule\Pricing\Price\CatalogRulePrice` which loads any active catalog rules.  
+  
+The performance struggles comes when you have a lot of active catalog rule loaded every team for each items on the page.
 
 ## Support