1. SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '3-53175' for key 'CATALOG_CATEGORY_PRODUCT_CATEGORY_ID_PRODUCT_ID', query was: INSERT INTO `catalog_category_product` (`category_id`,`product_id`) VALUES (?, ?), (?, ?)
Note: Why show this error "idle (1240 in backlog)"
![indexer-problem.png indexer-problem.png](https://community.magento.com/t5/image/serverpage/image-id/28671i79B68DA346F4F3C7/image-size/large?v=v2&px=999)