What is this Fatal error?
 

Hey friends I am trying to rebuild the thread cache and getting below error. Please help me to fix it.

Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 71 bytes) in /home/hostuser/public_html/includes/class_dm_threadpost.php on line 1237

Thanks in advance.

Are you using "Rebuild Post Cache" in the adminCP? Maybe try reducing the "Number of posts to process per cycle".

That error indicates that your php doesn't have enough memory allocated to complete the operation. You can either increase your memory_limit setting in php.ini to xxM (something larger than what you currently have) or to temporarily up your limits edit your includes/config.php file and add this line right under the <?php line:

ini_set("memory_limit", "xxM");

(You can view your current memory_limit in Maintenance > View PHP Info . If it's 16M, try 32M. If it's 32M, try 64M. If it's 64M, try 92M or 128M, etc.)

But, if you are only having the issue when rebuilding, then try a smaller number of posts as suggested.