[Bitrix\Main\DB\SqlQueryException] 
Mysql query error: (2006) MySQL server has gone away (400)
SHOW TABLES LIKE 'b_iblock_26_index_val'
/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/lib/db/mysqliconnection.php:137
#0: Bitrix\Main\DB\MysqliConnection->queryInternal(string, array, NULL)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/lib/db/connection.php:329
#1: Bitrix\Main\DB\Connection->query(string)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/lib/db/mysqlcommonconnection.php:48
#2: Bitrix\Main\DB\MysqlCommonConnection->isTableExists(string)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/iblock/lib/propertyindex/dictionary.php:54
#3: Bitrix\Iblock\PropertyIndex\Dictionary->isExists()
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/iblock/lib/propertyindex/facet.php:57
#4: Bitrix\Iblock\PropertyIndex\Facet->__construct(integer)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/iblock/lib/propertyindex/querybuilder.php:28
#5: Bitrix\Iblock\PropertyIndex\QueryBuilder->__construct(integer)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/iblock/classes/general/iblockelement.php:653
#6: CAllIBlockElement->MkFilter(array, array, array)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/iblock/classes/general/iblockelement.php:3091
#7: CAllIBlockElement->PrepareGetList(array, array, array, string, array, array, NULL, NULL, array, boolean, string, array, array, array)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/iblock/classes/mysql/iblockelement.php:340
#8: CIBlockElement->prepareSql(array, array, boolean, array)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/iblock/classes/mysql/iblockelement.php:642
#9: CIBlockElement::GetList(array, array, boolean, boolean, array)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/php_interface/init.php:312
#10: MyNewClass::MyOnBeforePrologHandler()
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/classes/general/module.php:475
#11: ExecuteModuleEventEx(array)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/include.php:564
#12: require_once(string)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/include/prolog_before.php:14
#13: require_once(string)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/include/prolog.php:10
#14: require_once(string)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/header.php:23
#15: require(string)
	/home/bitrix/ext_www/sigaretnik.ru/catalog/index.php:1
#16: include_once(string)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/include/urlrewrite.php:159
#17: include_once(string)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/urlrewrite.php:2
#18: include_once(string)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/ipol.aseo/work/urlrewrite.php:131
#19: include_once(string)
	/home/bitrix/ext_www/sigaretnik.ru/bitrix/js/ipol.aseo/urlrewrite.php:14

Fatal error: Uncaught Bitrix\Main\DB\SqlQueryException: Mysql query error: (2006) MySQL server has gone away in /home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/lib/db/mysqliconnection.php:137 Stack trace: #0 /home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/lib/db/mysqlcommonconnection.php(132): Bitrix\Main\DB\MysqliConnection->queryInternal('SELECT * FROM `...') #1 /home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/lib/db/connection.php(715): Bitrix\Main\DB\MysqlCommonConnection->getTableFields('b_sec_session') #2 /home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/lib/db/sqlhelper.php(387): Bitrix\Main\DB\Connection->getTableField('b_sec_session', 'SESSION_ID') #3 /home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/lib/entity/datamanager.php(917): Bitrix\Main\DB\SqlHelper->prepareAssignment('b_sec_session', 'SESSION_ID', 'WN02r1WBCNboZMj...') #4 /home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/security/classes/general/session_db.php(92): Bitrix\Main\Entity\DataManager::delete(Array) #5 [internal f in /home/bitrix/ext_www/sigaretnik.ru/bitrix/modules/main/lib/db/mysqliconnection.php on line 137