Added configuration for maximum number of records for aggregation

lib/mshoplib/src/MShop/Common/Manager/Base.php

@@ -237,6 +237,22 @@ protected function addSqlColumns( array $columns, string $sql, bool $mode = true
 	protected function aggregateBase( \Aimeos\MW\Criteria\Iface $search, $keys, string $cfgPath,
 		array $required = [], string $value = null, string $type = null ) : \Aimeos\Map
 	{
+		/** mshop/common/manager/aggregate/limit
+		 * Limits the number of records that are used when aggregating items
+		*
+		* As counting huge amount of records (several 10 000 records) takes a long time,
+		* the limit can cut down response times so the counts are available more quickly
+		* in the front-end and the server load is reduced.
+		*
+		* Using a low limit can lead to incorrect numbers if the amount of found items
+		* is very high. Approximate item counts are normally not a problem but it can
+		* lead to the situation that visitors see that no items are available despite
+		* the fact that there would be at least one.
+		*
+		* @param integer Number of records
+		* @since 2021.04
+		*/
+		$limit = $this->context->getConfig()->get( 'mshop/common/manager/aggregate/limit', 10000 );
 		$keys = (array) $keys;
 
 		if( !count( $keys ) ) {
@@ -252,6 +268,7 @@ protected function aggregateBase( \Aimeos\MW\Criteria\Iface $search, $keys, stri
 			$total = null;
 			$cols = $map = [];
 			$search = clone $search;
+			$search->slice( $search->getOffset(), min( $search->getLimit(), $limit ) );
 
 			$level = \Aimeos\MShop\Locale\Manager\Base::SITE_ALL;
 			$attrList = $this->getObject()->getSearchAttributes();

lib/mshoplib/src/MShop/Index/Manager/Standard.php

@@ -306,7 +306,7 @@ public function rebuild( iterable $items = [] ) : \Aimeos\MShop\Index\Manager\If
 			$search->setConditions( $search->compare( '==', 'product.id', $result->keys()->toArray() ) );
 			$this->writeIndex( $search, $domains, $size );
 
-			$start += $size;
+			$start += count( $result );
 		}
 		while( !$result->isEmpty() );