ID: 42356
Updated by: [EMAIL PROTECTED]
Reported By: myteamz at rogers dot com
Status: Bogus
Bug Type: Reproducible crash
Operating System: Windows XP SP2
PHP Version: 5.2.3
Assigned To: pajoye
New Comment:
"When I change my call to use imagecreatetruecolor instead of
imagecreate, the memory usage is exactly the same, suggesting the PHP
imagecreate is calling the GD gdImageCreateTrueColor and reducing the
available image size by a factor of 4. If this is the case, why?"
That's not the case. You consider the values returned by the memory
info functions are accurate, they are not.
"This implies that the default max image GD can handle (for height of
1024) is about 32M/1024/4 = 8K."
Completely wrong, you are looking at the wrong place to fix your
problem. If you have doubt about the cause (memory limit), try to run
your script (and only what you show here) using CLI (command line).
Previous Comments:
------------------------------------------------------------------------
[2007-08-21 15:25:35] myteamz at rogers dot com
With understanding of how much memory GD uses per pixel (4 bytes), I am
able to scale image request size to fit in memory, but result is that
image is not large enough to build tree.
When increasing memory_limit to 128M, I still run into 32M limit, and
upon looking further, it appears that default Apache Windows distro is
built with MAX_PROCESS_SIZE = 32M.
This implies that the default max image GD can handle (for height of
1024) is about 32M/1024/4 = 8K.
When looking further into GD documentation, there is a reason why I am
using imagecreate instead of imagecreatetruecolor. The GD docs say
gdImageCreate(sx, sy) has a 256 color limit, or 1 byte per pixel, while
gdImageCreateTrueColor(sx, sy) has "an essentially unlimited number of
colors" - presumably 32 bit or 4 bytes per pixel.
When I change my call to use imagecreatetruecolor instead of
imagecreate, the memory usage is exactly the same, suggesting the PHP
imagecreate is calling the GD gdImageCreateTrueColor and reducing the
available image size by a factor of 4. If this is the case, why?
------------------------------------------------------------------------
[2007-08-21 14:31:11] [EMAIL PROTECTED]
Your image takes 13770*990*4 bytes, which is ca. 54mb. That doesn't fit
in 32 mb memory limit.
------------------------------------------------------------------------
[2007-08-21 14:21:14] myteamz at rogers dot com
You have ignored the other submitted info that shows (via call to
memory_get_usage(true)) that the memory in use is actually less than
7M.
Either the function call is reporting incorrect values, or there is a
problem in the memory manager believing 32M is in use.
I have subsequently added a call to memory_get_peak_usage(true), and it
reports the same value as memory_get_usage(true), indicating I have come
nowhere near using 32M.
------------------------------------------------------------------------
[2007-08-21 05:48:22] [EMAIL PROTECTED]
"Fatal error: Allowed memory size of 33554432 bytes exhausted (tried
to
allocate 13770 bytes) in C:\Program Files\Apache Software"
I'm sorry but it has nothing to do with GD. imagecreate tries to
allocate the memory it needs for an image but your application seems to
have already used most of the available limit (32M in this case).
By the way, fatal errors are not crashes or do you have a real crash?
(segfault). If yes post a comment I will reopen this bug and move it to
the engine category.
------------------------------------------------------------------------
[2007-08-21 01:28:22] myteamz at rogers dot com
Description:
------------
I am creating a script to produce a PNG image of a chart showing common
ancestors of several individuals, using the gd functionality supplied
with php. After processing the input, including many calls to MySQL
(version 5.0.2) all running on Apache 2.2 on Windows XP SP2, I am trying
to allocate the image resource. This works for very small trees, but
fails on all calls with large trees.
The PHP error message is:
Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to
allocate 13770 bytes) in C:\Program Files\Apache Software
Foundation\Apache2.2\htdocs\GenChart\drawgraph.php on line 116
The offending code is:
$im = imagecreate ($xsize, $ysize);
Reproduce code:
---------------
Lots of memory allocation/freeing is occurring in the script prior to
this call. I have included several debug lines prior to the offending
call, as below:
$memMax = ini_get("memory_limit");
$memUsed = memory_get_usage(true);
$xMax = round(30000000-intval($memUsed/$ysize),-3);
$xsize = min($xMax,max($xsize,4000));
dumpData("have used $memUsed of $memMax memory");
dumpData("trying to create image of size ($xsize,$ysize)");
$im = imagecreate ($xsize, $ysize);
The output, on crash, is
have used 6815744 of 32M memory
trying to create image of size (13770,990)
Expected result:
----------------
I have changed the script to produce standard HTML output for debugging
purposes, which allows me to get this info. When running as intended,
with a small tree/image, the script should and does run successfully,
creating an image, and returning it as a .PNG image. Running the same
debug code for a small image (with no crash), the output is:
have used 6553600 of 32M memory
trying to create image of size (4000,690)
Actual result:
--------------
When running in debug mode for a large tree/image, the debug output
is:
have used 6815744 of 32M memory
trying to create image of size (13770,990)
When running as intended, the script fails and no image is returned to
the browser.
------------------------------------------------------------------------
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Edit this bug report at http://bugs.php.net/?id=42356&edit=1
