Magento, problem with catalog_product_flat - magento

Question

We have a website with 2 store views: FR and EN. For some products after import catalog_product_flat for EN store view is not refreshed. In EAV tables everything is fine. Data re-index should truncate this flat table and fill it with updated data. Somehow it doesn't work for some items.
Did anyone of you had a similar problem? I'd appreciate for any clues or advices on this topic.
EDIT
I have made further checks and I was wrong about EAV tables. It turns out that catalog_product_entity_varchar is consistent with catalog_product_flat. So flat table has the same data as EAV table but in the Admin Panel values are wrong. For EN store view they are the same as default values, only for some products (magic? ;)). On my local PC I didn't encounter such issue. This is only on our production environment. As far as I know we do not use any DB replication (which could be the issue here).

Answer 1

EAV database model is used by Magento for easy upgrade and development as this model gives more flexibility to play with data and attributes.
When flat catalog is enabled in Magento then all the above product attributes (id, name, price) are kept in one table named like catalog_product_flat. Then Magento fetches product data from the flat table rather than joining all the other smaller tables.
There are two types of Flat Catalog:
1) Flat Catalog Product
2) Flat Catalog Category
Flat Categories are recommended for any Magento installation for improved performance.
Flat Products is designed and recommended for catalogs that have over 1000 SKU’s.
Enable Flat Catalog Category:
Go to Admin Panel->System->Cache Management->Rebuild Flat Catalog Category
Go to Admin Panel->System->Configuration->Catalog->Frontend->Use Flat Catalog Category = Yes
Enable Flat Catalog Product:
Go to Admin Panel->System->Cache Management->Rebuild Flat Catalog Product
Go to Admin Panel->System->Configuration->Catalog->Frontend->Use Flat Catalog Product = Yes
Remember that, initially the selection list of
Admin Panel->System->Configuration->Catalog->Frontend->Use Flat Catalog Product
OR,
Admin Panel->System->Configuration->Catalog->Frontend->Use Flat Catalog Product
is non-editable. You have to rebuild Flat Catalog from Cache Management. Only then the selection list becomes editable.

Answer 2

Make sure that while importing of the Catalog Products, the required attributes of the products are provided with correct values in the import file. If this is not done properly, then Data re-index may not function correctly.
Also before re-indexing, it is always advisable & wise to clear the cache from the "Cache Management" & from the "cache" folder of your Magento installation directory.
Hope it helps.

Answer 3

I was wrong about what's wrong. And everything is OK with database. The problem was an order of attributes that are retrieved from DB.
In Mage_Eav_Model_Entity_Abstract we can find:
$selects = array();
foreach ($this->getAttributesByTable() as $table=>$attributes) {
$selects[] = $this->_getLoadAttributesSelect($object, $table);
}
if (!empty($selects)) {
$values = $this->_getReadAdapter()->fetchAll(implode(' UNION ', $selects));
foreach ($values as $valueRow) {
$this->_setAttribteValue($object, $valueRow);
}
}
Line implode(' UNION ', $selects) concatenates all select statements. But there is no ORDER BY, so data can be retrieved in random order. As a matter of fact, for some of the products it is like this. That select takes values of attributes for store view 0 (always) and selected store view (current one).
Array $values contains of arrays with attributes properties. Order does matter here, because if attribute (for example 'name') for store view e.g. 1 will be proceed before one for store view 0, then it will be overwritten.
Solution is to add ORDER BY clause to the $selects or sort $values array.