How can I keep the server from overloading?

Question

I made a while loop in php:

<?php
include_once("connect.php");

$search=mysql_query("SELECT * from chat ORDER BY id DESC LIMIT 1");
$row=mysql_fetch_assoc($search);
$type=$row['type'];
$id=$row['id'];
while($type!='n'){
  usleep(10000);
  $search=mysql_query("SELECT * from chat ORDER BY id DESC LIMIT 1");
  $row=mysql_fetch_assoc($search);
  $type=$row['type'];
}

$run=mysql_query("UPDATE chat SET type='o' WHERE id=$id");

mysql_close($conn);
echo $row['message'] . "<br/>";

?>

It always runs to see if there are new entries in the database, but I dont know what to do to keep the server from overloading. I tried usleep but I don't think it's enough.

Also I am getting this error "Fatal error: Maximum execution time of 60 seconds exceeded" and I know I can change the number of repetitions in the .ini file but would that be wise? Will it have a really bad effect on the servers performance?

Answer 1

Update

usleep(10000);
set_time_limit(11000);

First answer

What are you trying to achieve with this code? The timeout message comes from the script usleep(10000).

Your code cannot detect immediate user input, your PHP code will run between user interactions with the server.

If you want to create a chat utility:

• Send your messages via AJAX each time an user hits Enter or Send
• Store the message received, along with the timestamp of the message received
• Select an update time, say 3 seconds
• Update the chat via AJAX, each update time
• Return the message that are update time old, or newer