The "require_once(): Unable to allocate memory for pool" error in PHP can occur when PHP is unable to allocate memory for a new process or thread. This can be caused by a variety of factors, including insufficient memory resources, memory leaks, or other issues.
To fix this error, you can try the following solutions:
Increase the available memory for PHP: You can increase the available memory for PHP by modifying the memory_limit directive in the php.ini configuration file. For example, you can set the memory_limit directive to a higher value, such as 256M or 512M, depending on your system resources.
Check for memory leaks: Memory leaks can cause PHP to run out of memory, leading to the "Unable to allocate memory for pool" error. You can use tools such as Xdebug or Valgrind to detect and fix memory leaks in your PHP code.
Restart the PHP process: Restarting the PHP process can help to release any memory that may have been leaked or is no longer being used. You can restart the PHP process by restarting the web server or by running the kill command to terminate the PHP process and start a new one.
Check for other issues: There may be other issues that are causing the "Unable to allocate memory for pool" error, such as a faulty PHP extension or a misconfigured server. In this case, you may need to troubleshoot the issue further to identify the root cause and find a solution.
Keep in mind that the "Unable to allocate memory for pool" error can be caused by a variety of factors, and the appropriate solution will depend on the specific circumstances of your case. By following the steps outlined above, you should be able to fix the error and get your PHP code running smoothly.