`total_memory_tracker.setOrRaiseHardLimit(...);` in `ConfigReloader` callback (see `Server.cpp`).
if (pool_size < 1)
            throw Exception("distributed_ddl.pool_size should be greater then 0", ErrorCodes::ARGUMENT_OUT_OF_BOUND);
        global_context->setDDLWorker(std::make_unique<DDLWorker>(pool_size, ddl_zookeeper_path, *global_context, &config(), "distributed_ddl"));
    }
    std::unique_ptr<DNSCacheUpdater> dns_cache_updater;
    if (config().has("disable_internal_dns_cache") && config().getInt("disable_internal_dns_cache"))
    {
        
        DNSResolver::instance().setDisableCacheFlag();
        LOG_DEBUG(log, "DNS caching disabled");
    }
    else
    {
        
        dns_cache_updater = std::make_unique<DNSCacheUpdater>(*global_context, config().getInt("dns_cache_update_period", 15));
    }
#if defined(OS_LINUX)
    if (!TasksStatsCounters::checkIfAvailable())
    {
        LOG_INFO(log, "It looks like this system does not have procfs mounted at /proc location,"
            " neither clickhouse-server process has CAP_NET_ADMIN capability."
            " 'taskstats' performance statistics will be disabled."
            " It could happen due to incorrect ClickHouse package installation."
            " You can try to resolve the problem manually with 'sudo setcap cap_net_admin=+ep {}'."
            " Note that it will not work on 'nosuid' mounted filesystems."
            " It also doesn't work if you run clickhouse-server inside network namespace as it happens in some containers.",
            executable_path);
    }
    if (!hasLinuxCapability(CAP_SYS_NICE))
    {