[GENERAL] Two-phase commit case studies

Hello,

I've read the documentation for two-phase commit and it sounds interesting, but
I'm having trouble thinking of how to actually put it into production. How are
people using it? Do you use a XA transaction manager or something custom built?
How dos the reconciliation work when a component crashes between PREPARE and
COMMIT? Is anyone using it in the open-source world where transaction managers
are unheard of?

Looking forward to hearing about how two-phase commit has helped you.

Thanks