if ( ! empty( $category->tag_count ) ) {
			$have_tags = true;
			$count     = (int) $category->tag_count;
			$taxonomy  = 'post_tag';
			$wpdb->insert( $wpdb->term_taxonomy, compact( 'term_id', 'taxonomy', 'description', 'parent', 'count' ) );
			$tt_ids[ $term_id ][ $taxonomy ] = (int) $wpdb->insert_id;
		}

		if ( empty( $count ) ) {
			$count    = 0;
			$taxonomy = 'category';
			$wpdb->insert( $wpdb->term_taxonomy, compact( 'term_id', 'taxonomy', 'description', 'parent', 'count' ) );
			$tt_ids[ $term_id ][ $taxonomy ] = (int) $wpdb->insert_id;
		}
	}

	$select = 'post_id, category_id';
	if ( $have_tags ) {
		$select .= ', rel_type';
	}

	$posts = $wpdb->get_results( "SELECT $select FROM $wpdb->post2cat GROUP BY post_id, category_id" );
	foreach ( $posts as $post ) {
		$post_id  = (int) $post->post_id;
		$term_id  = (int) $post->category_id;
		$taxonomy = 'category';
		if ( ! empty( $post->rel_type ) && 'tag' == $post->rel_type ) {
			$taxonomy = 'tag';
		}
		$tt_id = $tt_ids[ $term_id ][ $taxonomy ];
		if ( empty( $tt_id ) ) {
			continue;
		}

		$wpdb->insert(
			$wpdb->term_relationships,
			array(
				'object_id'        => $post_id,
				'term_taxonomy_id' => $tt_id,
			)
		);
	}

	// < 3570 we used linkcategories. >= 3570 we used categories and link2cat.
	if ( $wp_current_db_version < 3570 ) {
		/*
		 * Create link_category terms for link categories. Create a map of link
		 * cat IDs to link_category terms.
		 */
		$link_cat_id_map  = array();
		$default_link_cat = 0;
		$tt_ids           = array();
		$link_cats        = $wpdb->get_results( 'SELECT cat_id, cat_name FROM ' . $wpdb->prefix . 'linkcategories' );
		foreach ( $link_cats as $category ) {
			$cat_id     = (int) $category->cat_id;
			$term_id    = 0;
			$name       = wp_slash( $category->cat_name );
			$slug       = sanitize_title( $name );
			$term_group = 0;

			// Associate terms with the same slug in a term group and make slugs unique.
			if ( $exists = $wpdb->get_results( $wpdb->prepare( "SELECT term_id, term_group FROM $wpdb->terms WHERE slug = %s", $slug ) ) ) {