Item (Magento\Catalog\Model\Product\Interceptor) with the same ID "##" already exists.

[Stylish015]

Using the in-built Product Importer we have been successfully updating our product quantities in bulk within Mangeto 2.0.5.

However since we have upgraded to Magento 2.1.0, and after a Product Import updating qty's, we get an error:
Item (Magento\Catalog\Model\Product\Interceptor) with the same ID "4" already exists.

This error shows in the Admin while trying to view products on "Products -> Catalog"

Steps to reproduce

1. Create a csv with two columns "sku" & "qty", with the existing sku's and new product qty's
2. Upload csv within "System -> Import" selecting:
3. Entity Type: Products
4. Import Behavior: Add/Update
5. The csv checks fine (no errors) and the import is successful.
6. Then in the Admin go to ""Products -> Catalog" get the error "Item (Magento\Catalog\Model\Product\Interceptor) with the same ID "4" already exists. "

Expected result

For the import to be successful.
It updates the product quantities successfully.
You can still view products in the Admin at "Products -> Catalog"

Actual result

While viewing Products in the Admin at "Products -> Catalog" get the error:
Item (Magento\Catalog\Model\Product\Interceptor) with the same ID "4" already exists.

Is this a bug?
Can it be fixed so we can view our products in the Admin?

Thanks.

[Sam-PUMP]

Exact same thing here... let me know if you find a solution

[piotrekkaminski]

One of our clients run into similar issue recently and found out there were duplicate product IDs in the database each with different Store IDs (1 and 2). They ended up deleting products with Store ID 2 as a workaround. Hope it helps.

[vishveskrish]

We are facing the same error, Is there any permanent fix ?

[GordonLesti]

We have the same problem with Item (Magento\Catalog\Model\Product\Interceptor) with the same ID "3523" already exists. if we search a product by the name Raff in the Backend of Magento 2.1.

It seems that the query is producing duplicated rows when joining cataloginventory_stock_item. This query is fetched in Magento\Eav\Model\Entity\Collection\AbstractCollection::_loadEntities. The exception will be thrown in Magento\Framework\Data\Collection::addItem cause we have two entities with the same ID.
The causing query looks like this:

SELECT `e`.*, IF(at_name.value_id > 0, at_name.value, at_name_default.value) AS `name`, `at_qty`.`qty` FROM `catalog_product_entity` AS `e`
 INNER JOIN `catalog_product_entity_varchar` AS `at_name_default` ON (`at_name_default`.`entity_id` = `e`.`entity_id`) AND (`at_name_default`.`attribute_id` = '70') AND `at_name_default`.`store_id` = 0
 LEFT JOIN `catalog_product_entity_varchar` AS `at_name` ON (`at_name`.`entity_id` = `e`.`entity_id`) AND (`at_name`.`attribute_id` = '70') AND (`at_name`.`store_id` = 1)
 LEFT JOIN `cataloginventory_stock_item` AS `at_qty` ON (at_qty.`product_id`=e.entity_id) AND (at_qty.stock_id=1) WHERE (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') AND (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') AND (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') AND (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') AND (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') AND (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') AND (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') AND (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') AND (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') AND (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') AND (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') AND (IF(at_name.value_id > 0, at_name.value, at_name_default.value) LIKE '%Raff%') ORDER BY `e`.`entity_id` ASC
 LIMIT 20;

The LEFT JOIN cataloginventory_stock_item ... creates the duplicate row and a GROUP BY e.entity_id`` can solve that.

We just have to find out, where we can add that in the code 😄.

[GordonLesti]

A groupByAttribute on the collection in Magento\Catalog\Ui\DataProvider\Product\ProductDataProvider::getData fixed the problem temporary.

    /**
     * Get data
     *
     * @return array
     */
    public function getData()
    {
        $this->getCollection()->groupByAttribute('entity_id');
        if (!$this->getCollection()->isLoaded()) {
            $this->getCollection()->load();
        }
        $items = $this->getCollection()->toArray();

        return [
            'totalRecords' => $this->getCollection()->getSize(),
            'items' => array_values($items),
        ];
    }

[vishveskrish]

Hi Gordon,

This is temporary fix but its not the solution as M2 adding duplicate entries on "cataloginventory_stock_item" table while importing the products.

We need to fix this issue as soon as possible.

While updating any products it is re-entering the new rows for updated products .

Thanks,
Vishves Shah

[sevos1984]

This is a known issue MAGETWO-57490, thanks for posting

[phamngsinh]

vendor/magento/framework/Data/Collection.php

line : 406

 public function addItem(\Magento\Framework\DataObject $item)
    {
        $itemId = $this->_getItemId($item);

        if ($itemId !== null) {
            if (isset($this->_items[$itemId])) {
                throw new \Exception(
                    'Item (' . get_class($item) . ') with the same ID "' . $item->getId() . '" already exists.'
               );
            }
            $this->_items[$itemId] = $item;
        } else {
            $this->_addItem($item);
        }
        return $this;
    }

become => below, wait for M2 fix
public function addItem(\Magento\Framework\DataObject $item)
{
$itemId = $this->_getItemId($item);

    if ($itemId !== null) {
        if (isset($this->_items[$itemId])) {
        return $this;
        }
        $this->_items[$itemId] = $item;
    } else {
        $this->_addItem($item);
    }
    return $this;
}

[Mahmoud-Refaat]

This problem exist duo to difference between products "website_id" value and default value in Magneto 2 Table: cataloginventory_stock_item

So do the following :
1- check the default value for your site it will be at table cataloginventory_stock
2- then compare it to the existing products at Table: cataloginventory_stock_item
in my case it was 0 while products website_id were 1 so to solve this run the following SQL
UPDATE cataloginventory_stock_item SET website_id=0

[johnverzijden]

Like above said, Magento 2 admin is not preped for diff website_id 's in the stock item table. I had to use different website_id. In case You would like to use stock per website you could preference (admin di.xml) the "Magento\CatalogInventory\Ui\DataProvider\Product\AddQuantityFieldToCollection" and add "AND {{table}}.website_id=0".

{{table}}.stock_id=1 AND {{table}}.website_id=0