Question

I have a custom multi select attribute which I’d like to take part in filtering of products. The attribute is set as used in Layered Navigation however doesn’t appear in the list of available filters. Could be due to custom model implementation?
Anyone have some tips where to check why it doesn’t appear? Attribute is set for several products
Magento version used is EE 1.11

Thanks

Answer 1

What is the backend_type. i.e. are the values stored in the catalog_product_entity_varchar or catalog_product_entity_text table?
The backend_type has to match the checks in Mage_Catalog_Model_Resource_Eav_Attribute::isIndexable(), so text wouldn’t work without rewriting the attribute model.

Is the is_filterable and/or is_filterable_in_search attribute property set?
The Mage_Catalog_Model_Product_Indexer_Eav::_registerCatalogAttributeSaveEvent() checks for those when updating the index for the layered navigation.

Are the methods getFlatColums(), getFlatIndexes() and getFlatUpdateSelect() implemented in the custom source model?
This actually is only required for building and updating the flat catalog product tables (so the used_in_product_listing or is_filterable property needs to be set in order for Magento to pick up the attribute).
Check the class Mage_Eav_Model_Entity_Attribute_Source_Table as a reference on what these there methods are supposed to return.