I recently upgraded a system from php 4.4.2 to php 5.2.1, and one of my scripts has started behaving very strangely. I've tried google but come up blank so far.

Basically what the script does is select a large amount of data from a mysql (4.1.21) database, do some manipulation, the plots a graph (using jpgraph 2.2). I removed all the jpgraph code and am still getting the problem. What happens is the script 'hangs' for a period of time after executing the last php command before actually exiting. During this period of time the process takes up a large amount of CPU time (a whole single processor mostly) but if you truss the process you get no output until it finally exits (when you see stdin/out/err closed etc).

After putting various debug statements in I found that if I commented out the following line the script didn't hang before exiting.

$datax = $newdatax;

A pretty innocuous line. At this point $datax is a large array (many thousands of values long), and $newdatax an array with the results from parsing the original $datax in some way (mostly a case of taking every Nth entry from $datax). At this point I wish to throw away the original $datax and replace it with the new $newdatax and I may wish to do more maniplulation later.

If $datax is about 10000 or so rows there is a noticeable hang when the script exits, at 50000 rows the hang is over 20 seconds. Under php 4 I had no problems with this code when there were over 200,000 rows in the array.

Even if I simply change that line to

$datax = array();

I get similar (but much smaller) 'hang' before the script exits and the $datax array needs to be quite large before it becomes noticeable.

System is running on Solaris 9 on a v480 with 4 processors and 16GB of RAM. I've tried it with and without the Zend optimiser (v3.2.8) with no noticeable difference.

Any help appreciated.