According to the XL language specification, the XL queries are applied in parallel. In order to make sure the queries and rules are applied in parallel without concurrency access, GroIMP implementation use transactions and queues.

GroIMP transactions work as buffers of operations on the graph. A transaction includes a set of queues that contains the

During, one RGG method a transaction is automatically get (created if needed) and all modifications are pushed into

Each RGG method automatically start a transaction