I use composer for my daily development needs and I love it. Usually everything is okay but when I worked on a Sylius project that has lots of dependencies sometimes it got stuck when I tried to do

    composer update

A few days later my colleague stumbled upon a github issue that basically says composer has a problem with memory.

So I bumped my Vagranfile from default 384 MB to 1024MB and later on when I used composer update command it took a while but it completed it successfully.

If for some reason you still get errors you can try manually updating the memory limit like this:

php -d memory_limit=-1 composer.phar update

-d stands for define. You can also use it as -define.