php - MySQL server has gone away error on server -

i have following code storing info arxiv.org pages in mysql

function paper_info($paper_id){     $url = 'http://arxiv.org/abs/'.$paper_id;     $options = array('http'=>array('method'=>"get", 'header'=>"user-agent: mozilla/5.0 (windows nt 6.1; trident/7.0; rv:11.0) gecko\r\n"));     $context = stream_context_create($options);     $sites_html = file_get_contents($url, false, $context);     $html = new domdocument();     @$html->loadhtml($sites_html);     $title = null;     foreach($html->getelementsbytagname('meta') $meta) {         if($meta->getattribute("name")=="citation_title"){              $title = $meta->getattribute('content');         }     }     if(preg_match('~<blockquote class="abstract mathjax">(.*?)</blockquote>~si', $sites_html, $match)){         $abstract = trim(preg_replace('#<span class="descriptor">(.*?)</span>#', '', $match[1]));     }         return array($title, $abstract); }             $paper_id = "1509.05363v1";             if(!isset($paper_info)) $paper_info = paper_info($paper_id);                     mysql_query("insert `data` (`id`, `action`, `value`) values (null, 'submit', '0');");               mysql_query("insert `data` (`id`, `action`, `value`) values (null, 'paper id', '".$paper_id."');");             mysql_query("insert `data` (`id`, `action`, `value`) values (null, 'title', '".mysql_real_escape_string($paper_info[0])."');");             mysql_query("insert `data` (`id`, `action`, `value`) values (null, 'abstract', '".mysql_real_escape_string($paper_info[1])."');");  

the code works fine on localhost however, when uploaded site on online server error happens

mysql server has gone away

i tried increasing max_allowed_packet suggested in mysql error 2006: mysql server has gone away adding line

mysql_query("set global max_allowed_packet = 1073741824;"); 

but error still happens. know why happens?

after trying

mysql_query("set session wait_timeout = 300;"); mysql_query("set global interactive_timeout=300;"); mysql_query("set global wait_timeout=300;"); 

the error doesn't happen function paper_info return empty value on server works fine on localhost. why happening?

have tried setting wait_timeout , interactive_timeout value?

example:

set global wait_timeout=300;  set global interactive_timeout=300;