ID: 10204
User Update by: [EMAIL PROTECTED]
Status: Open
Bug Type: Sockets related
Description: fgets causes memory leaks

> Um, yes, the memory usage increases because you are appending an infinite number of 
>copies
of the google page to your $page variable.

No, that's what the unset is for.

Anyways, here's memory statistics.

On loading script one: 3740kb RAM used after two iterations (RAM should not increase 
above this level).

After 5 minutes: 4130kb.

Cf script two: 3752kb RAM used initially, and 3752kb after 5 minutes. 

These statistics aren't especially dramatic, but in other conditions it can be 
catastrophic.

Regarding fclose, no this doesn't help.

There is a problem with fgets but not fread.

Previous Comments:
---------------------------------------------------------------------------

[2001-04-09 06:58:37] [EMAIL PROTECTED]
> Um, yes, the memory usage increases because you are appending an infinite number of 
>copies
of the google page to your $page variable.

No, that's what the unset is for.

Anyways, here's memory statistics.

On loading script one: 3740kb RAM used after two iterations (RAM should not increase 
above this level).

After 5 minutes: 4130kb.

Cf script two: 3752kb RAM used initially, and 3752kb after 5 minutes. 

These statistics aren't especially dramatic, but in other conditions it can be 
catastrophic.

Regarding fclose, no this doesn't help.

There is a problem with fgets but not fread.

---------------------------------------------------------------------------

[2001-04-06 09:19:49] [EMAIL PROTECTED]
Um, yes, the memory usage increases because you are appending an infinite number of 
copies of the google page to your $page variable.

I can't see any leak in PHP - no leaks are reported by the memory manager.

Can you give me more information about how the memory usage increases, and what you 
would expect it to be?

Could you try explicitly fclose()ing your $fps too - you might find it useful in 
reducing memory cost.

--Wez.

---------------------------------------------------------------------------

[2001-04-06 08:54:33] [EMAIL PROTECTED]
I noticed this last night in the socket code: it uses a simple read-buffering scheme 
where the read buffer will only grow, so we are effectively storing the everything we 
have read in memory.

However, I would expect the behaviour to be the same with fread.

I take it the memory usage returns to normal once the page has completed?

--Wez.

---------------------------------------------------------------------------

[2001-04-06 07:54:22] [EMAIL PROTECTED]
Try this script (tested on windows, linux and open BSD(:

<?php
set_time_limit(0);
while (1) {
  unset($page);
  print "iteration ". ++$c;
  $fp = fsockopen("google.com", 80);
  fwrite($fp, "GET / HTTP/1.0rnrn");
  while (!feof($fp)) {
    $page .= fgets($fp, 1000);
  }
}
?>

Run it with top or whatever running and watch the memory usage go up and up (not 
especially quickly because the page is small, but in certain situations I've had 
memory chewage of 1mb/minute).

Now cf.

<?php
set_time_limit(0);
while (1) {
  unset($page);
  print "iteration ". ++$c;
  $fp = fsockopen("google.com", 80);
  fwrite($fp, "GET / HTTP/1.0rnrn");
  while (!feof($fp)) {
    $page .= fread($fp, 1000);
  }
}
?>

Memory usage remains constant here.

[This meant I had to rewrite the readLine method in Net_Socket to use fread instead of 
fgets.]

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Full Bug description available at: http://bugs.php.net/?id=10204


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