Magento 2: Category Pages from Page 2 shows without products always

Question

I'm trying to migrate a Magento 1.9.3.6 to Magento 2.3 and I found a strange problem. I've got some categories with thousands of products, I can see 64 products in my first page or 16, but if I go to page 2 http://v2.dendago.eus/moda?p=2 it says that there is no product. In any category happens the same. I've re-indexed and cleaned cache multiple times.

Any advice?

Answer 1

Look at the file vendor\magento\module-elasticsearch\Model\ResourceModel\Fulltext\Collection\SearchResultApplier.php

Find apply() method and replace it with the below function. Magento recently introduced hotfix by adding $this->collection->setPageSize(null); to the SearchResultApplier.php class.

public function apply()
    {
        if (empty($this->searchResult->getItems())) {
            $this->collection->getSelect()->where('NULL');
            return;
        }
        $ids = [];
        foreach ($this->searchResult->getItems() as $item) {
            $ids[] = (int)$item->getId();
        }
        $this->collection->setPageSize(null);
        $this->collection->getSelect()->where('e.entity_id IN (?)', $ids);
        $orderList = join(',', $ids);
        $this->collection->getSelect()->reset(\Magento\Framework\DB\Select::ORDER);
        $this->collection->getSelect()->order("FIELD(e.entity_id,$orderList)");
    }

Add a plugin on above class.