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[Bitrix\Main\DB\SqlQueryException] 
Mysql query error: (2006) MySQL server has gone away (400)
SELECT 
	`sale_internals_discount_entities`.`ID` AS `ID`
FROM `b_sale_discount_entities` `sale_internals_discount_entities` 
LEFT JOIN `b_sale_discount` `sale_internals_discount_entities_active_discount` ON `sale_internals_discount_entities`.`DISCOUNT_ID` = `sale_internals_discount_entities_active_discount`.`ID`
WHERE `sale_internals_discount_entities`.`MODULE_ID` = 'catalog'
AND `sale_internals_discount_entities`.`ENTITY` = 'PRICE'
AND `sale_internals_discount_entities`.`FIELD_ENTITY` = 'CATALOG_GROUP_ID'
AND `sale_internals_discount_entities`.`FIELD_TABLE` = 'CATALOG_GROUP_ID'
AND `sale_internals_discount_entities_active_discount`.`ACTIVE` = 'Y'
LIMIT 0, 1

/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/entity/query.php:3038
#2: Bitrix\Main\Entity\Query->query(string)
	/home/bitrix/www/bitrix/modules/main/lib/entity/query.php:797
#3: Bitrix\Main\Entity\Query->exec()
	/home/bitrix/www/bitrix/modules/main/lib/entity/datamanager.php:290
#4: Bitrix\Main\Entity\DataManager::getList(array)
	/home/bitrix/www/bitrix/modules/catalog/general/product.php:2431
#5: CAllCatalogProduct::initSaleSettings()
	/home/bitrix/www/bitrix/modules/catalog/general/product.php:1078
#6: CAllCatalogProduct::GetOptimalPrice(integer, double, array, string, array, string, array)
	/home/bitrix/www/bitrix/components/bitrix/catalog.element/class.php:134
#7: CatalogElementComponent->initAdditionalCacheKeys(array)
	/home/bitrix/www/bitrix/modules/iblock/lib/component/element.php:689
#8: Bitrix\Iblock\Component\Element->getCacheKeys()
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:3532
#9: Bitrix\Iblock\Component\Base->initResultCache()
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:3976
#10: Bitrix\Iblock\Component\Base->loadData()
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:3956
#11: Bitrix\Iblock\Component\Base->initialLoadAction()
	/home/bitrix/www/bitrix/modules/iblock/lib/component/element.php:229
#12: Bitrix\Iblock\Component\Element->initialLoadAction()
	
#13: call_user_func(array)
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:4141
#14: Bitrix\Iblock\Component\Base->doAction()
	/home/bitrix/www/bitrix/modules/iblock/lib/component/base.php:4159
#15: Bitrix\Iblock\Component\Base->executeComponent()
	/home/bitrix/www/bitrix/modules/main/classes/general/component.php:638
#16: CBitrixComponent->includeComponent(string, array, boolean)
	/home/bitrix/www/bitrix/modules/main/classes/general/main.php:1041
#17: CAllMain->IncludeComponent(string, string, array, boolean)
	/home/bitrix/www/catalog/detail.php:160
#18: include(string)
	/home/bitrix/www/catalog/index.php:7
#19: include_once(string)
	/home/bitrix/www/bitrix/modules/main/include/urlrewrite.php:159
#20: include_once(string)
	/home/bitrix/www/bitrix/urlrewrite.php:2

Fatal error: Uncaught Bitrix\Main\DB\SqlQueryException: Mysql query error: (2006) MySQL server has gone away in /home/bitrix/www/bitrix/modules/main/lib/db/mysqliconnection.php:137 Stack trace: #0 /home/bitrix/www/bitrix/modules/main/lib/db/mysqlcommonconnection.php(132): Bitrix\Main\DB\MysqliConnection->queryInternal('SELECT * FROM `...') #1 /home/bitrix/www/bitrix/modules/main/lib/db/connection.php(716): Bitrix\Main\DB\MysqlCommonConnection->getTableFields('b_sec_session') #2 /home/bitrix/www/bitrix/modules/main/lib/db/sqlhelper.php(387): Bitrix\Main\DB\Connection->getTableField('b_sec_session', 'SESSION_ID') #3 /home/bitrix/www/bitrix/modules/main/lib/entity/datamanager.php(974): Bitrix\Main\DB\SqlHelper->prepareAssignment('b_sec_session', 'SESSION_ID', 'j2FK9445V4uRh8e...') #4 /home/bitrix/www/bitrix/modules/security/classes/general/session_db.php(92): Bitrix\Main\Entity\DataManager::delete(Array) #5 [internal function]: CSecuritySessionDB::write('j2FK9445V4uRh8e...', 'SESS_AUTH|a:1:{...') #6 [internal function]: sess in /home/bitrix/www/bitrix/modules/main/lib/db/mysqliconnection.php on line 137