Craft CMS's tasks, depenging on what has to be accomplished, can be very tough on memory. For exemple, if you try to get and update hundred of entries, you may run out of memory.
This plugin breaks a task's steps into configurable batches and run these batches in a child process.
Download and unzip in Craft's plugin folder, be sure to rename the folder to taskscli
By default, the plugin will aim to make 25 steps per batch. To configure this setting, copy the config.php file in the repo, paste it in your craft/config folder and rename it taskscli.php
Make sure that you have the runTasksAutomatically setted to false in your config.
You can run the tasks by calling the runTasks command through Craft
$ php craft/app/etc/console/yiic taskscli runTasks
Ideally, You should setup a cron to do so.
*/1 * * * /usr/bin/php craft/app/etc/console/yiic taskscli runTasks >> craft/storage/runtime/logs/taskscli.log 2>&1