Performance: Issue with a lot of configurable with lots of images

[paales]

Preconditions

1. 2.1.2

Steps to reproduce

1. Create a lot of configurables with simples with images.
2. Load a category page.

Expected result

1. Loads only the media gallery images required and doesn't spend more than a second per query on the media gallery images.

Actual result

1. Loads all images and spends about a second per query, resulting in 20000ms added to the page load.

Below the following line:

magento2/app/code/Magento/Catalog/Model/ResourceModel/Product/Collection.php

Lines 2178 to 2181 in 1ade3b7

	$select = $this->getMediaGalleryResource()->createBatchBaseSelect(
	$this->getStoreId(),
	$attribute->getAttributeId()
	);

Add

$select->where('entity.entity_id IN(?)', $this->getLoadedIds());

[choukalos]

Tracking internally as MAGETWO-59138

[kandy]

Duplicate #6850

[paales]

@kandy Thanks for the reference!