Enabling Use Flat Catalog Products Results In Frontend Pages Not Loading

Question

I am running Magento 1.9.3.8 and would like to enable Use Flat Catalog Product as I have over 100k skus.

After enabling it, rebuilding the indexes, and clearing cache, the frontend will not load. It continuously spins until the server crashes. There are no errors regarding this in any of the logs, and I believe that is because the page never finishes loading?

Magento Admin works fine after enabling.

Use Flat Catalog Category works without issue.

How can I debug this issue if I do not receive any errors and the pages never load? Does anyone have any idea where to start? I can provide additional details if needed.

Answer 1

Use Flat Catalog Product tells Magento to use the flat database table for the catalog/product model. This is a flattened database table that has every attribute this model uses, which makes it faster than the standard EAV tables for this data.

Likely what is happening is your templates or blocks are attempting to use an attribute that is not in this flat table.

Magento determines which attributes should be added to the flat table based on the attribute's configuration. To add attributes to the flat table, edit them in the admin and select Used in Product Listing.

Then, reindex the site and clear your cache.

If you add all of the used attributes to the flat table using this method the page should render properly.

Good luck!