[Bitrix\Main\DB\SqlQueryException] 
Mysql query error: (2006) MySQL server has gone away (400)
SELECT 
	`catalog_catalog_iblock`.`IBLOCK_ID` AS `IBLOCK_ID`,
	`catalog_catalog_iblock`.`PRODUCT_IBLOCK_ID` AS `PRODUCT_IBLOCK_ID`,
	`catalog_catalog_iblock`.`SKU_PROPERTY_ID` AS `SKU_PROPERTY_ID`
FROM `b_catalog_iblock` `catalog_catalog_iblock` 

WHERE `catalog_catalog_iblock`.`IBLOCK_ID` IN (50,51)
AND (`catalog_catalog_iblock`.`PRODUCT_IBLOCK_ID` IS NOT NULL AND `catalog_catalog_iblock`.`PRODUCT_IBLOCK_ID` <> 0)
/home/bitrix/www/bitrix/modules/main/lib/db/mysqliconnection.php:137
#0: Bitrix\Main\DB\MysqliConnection->queryInternal(string, array, NULL)
	/home/bitrix/www/bitrix/modules/main/lib/db/connection.php:330
#1: Bitrix\Main\DB\Connection->query(string)
	/home/bitrix/www/bitrix/modules/main/lib/orm/query/query.php:3304
#2: Bitrix\Main\ORM\Query\Query->query(string)
	/home/bitrix/www/bitrix/modules/main/lib/orm/query/query.php:816
#3: Bitrix\Main\ORM\Query\Query->exec()
	/home/bitrix/www/bitrix/modules/main/lib/orm/data/datamanager.php:500
#4: Bitrix\Main\ORM\Data\DataManager::getList(array)
	/home/bitrix/www/bitrix/modules/catalog/lib/discount/discountmanager.php:1071
#5: Bitrix\Catalog\Discount\DiscountManager::getProductIblocks(array)
	/home/bitrix/www/bitrix/modules/catalog/lib/discount/discountmanager.php:654
#6: Bitrix\Catalog\Discount\DiscountManager::preloadProductDataToExtendOrder(array, array)
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:492
#7: Bitrix\Iblock\Component\Base->initCatalogDiscountCache()
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:4001
#8: Bitrix\Iblock\Component\Base->prepareData()
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:3955
#9: Bitrix\Iblock\Component\Base->processResultData()
	/home/bitrix/www/bitrix/components/bitrix/catalog.section/class.php:91
#10: CatalogSectionComponent->processResultData()
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:4453
#11: Bitrix\Iblock\Component\Base->loadData()
	/home/bitrix/www/bitrix/modules/iblock/lib/component/elementlist.php:1201
#12: Bitrix\Iblock\Component\ElementList->loadData()
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:4442
#13: Bitrix\Iblock\Component\Base->initialLoadAction()
	/home/bitrix/www/bitrix/components/bitrix/catalog.section/class.php:333
#14: CatalogSectionComponent->initialLoadAction()
	
#15: call_user_func(array)
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:4627
#16: Bitrix\Iblock\Component\Base->doAction()
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:4645
#17: Bitrix\Iblock\Component\Base->executeComponent()
	/home/bitrix/www/bitrix/modules/main/classes/general/component.php:648
#18: CBitrixComponent->includeComponent(string, array, object)
	/home/bitrix/www/bitrix/modules/main/classes/general/main.php:1039
#19: CAllMain->IncludeComponent(string, string, array, object)
	/home/bitrix/www/bitrix/templates/megamart_default/components/bitrix/catalog/catalog/section.php:705
#20: include(string)
	/home/bitrix/www/bitrix/modules/main/classes/general/component_template.php:725
#21: CBitrixComponentTemplate->__IncludePHPTemplate(array, array, string)
	/home/bitrix/www/bitrix/modules/main/classes/general/component_template.php:820
#22: CBitrixComponentTemplate->IncludeTemplate(array)
	/home/bitrix/www/bitrix/modules/main/classes/general/component.php:745
#23: CBitrixComponent->showComponentTemplate()
	/home/bitrix/www/bitrix/modules/main/classes/general/component.php:693
#24: CBitrixComponent->includeComponentTemplate(string)
	/home/bitrix/www/bitrix/components/bitrix/catalog/component.php:171
#25: include(string)
	/home/bitrix/www/bitrix/modules/main/classes/general/component.php:604
#26: CBitrixComponent->__includeComponent()
	/home/bitrix/www/bitrix/modules/main/classes/general/component.php:663
#27: CBitrixComponent->includeComponent(string, array, boolean)
	/home/bitrix/www/bitrix/modules/main/classes/general/main.php:1039
#28: CAllMain->IncludeComponent(string, string, array, boolean)
	/home/bitrix/www/catalog/index.php:1272
#29: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include/urlrewrite.php:159
#30: include_once(string)
	/home/bitrix/www/bitrix/urlrewrite.php:2