CREATE TABLE `ttlsa_com`.`create_id` ( 
`id` BIGINT( 20 ) NOT NULL AUTO_INCREMENT PRIMARY KEY
) ENGINE = MYISAM 

<?php 
function get_AI_ID() { 
 $sql = "insert into create_id (id) values('')"; 
 $this->db->query($sql); 
 return $this->db->insertID(); 
} 
?> 

function get_next_autoincrement_waitlock($timeout = 60){
 $count = $timeout > 0 ? $timeout : 60;
 
 while($r->get("serial:lock")){
 $count++;
 sleep(1);
 if ($count > 10)
 return false;
 }
 
 return true;
}
 
function get_next_autoincrement($timeout = 60){
 // first check if we are locked...
 if (get_next_autoincrement_waitlock($timeout) == false)
 return 0;
 
 $id = $r->incr("serial");
 
 if ( $id > 1 )
 return $id;
 
 // if ID == 1, we assume we do not have "serial" key...
 
 // first we need to get lock.
 if ($r->setnx("serial:lock"), 1){
 $r->expire("serial:lock", 60 * 5);
 
 // get max(id) from database.
 $id = select_db_query("select max(id) from user_posts");
 // or alternatively:
 // select id from user_posts order by id desc limit 1
 
 // increase it
 $id++;
 
 // update Redis key
 $r->set("serial", $id);
 
 // release the lock
 $r->del("serial:lock");
 
 return $id;
 }
 
 // can not get lock.
 return 0;
}
 
$r = new Redis();
$r->connect("127.0.0.1", "6379");
 
$id = get_next_autoincrement();
if ($id){
  $sql = "insert into user_posts(id,user,message)values($id,'$user','$message')"
  $data = exec_db_query($sql);
}

<?php
 
class common {
 
 private $r;
 
 function construct() {
  $this->__construct();
 }
 
 public function __construct(){
  $this->r=new Redis();
  $this->r->connect('127.0.0.1', 6379);
 }
 
 function set_queue_id($ids){
  if(is_array($ids) && isset($ids)){
  foreach ($ids as $id){
  $this->r->LPUSH('next_autoincrement',$id);
  }
  }
 }
 
 function get_next_autoincrement(){
  return $this->r->LPOP('next_autoincrement');
 }
 
}
 
$createid=array();
while(count($createid)<20){
 $num=rand(1000,4000);
 if(!in_array($num,$createid))
  $createid[]=$num;
}
 
$id=new common();
$id->set_queue_id($createid);
 
var_dump($id->get_next_autoincrement());