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:global.trans/2

As explained in Elixir in Action, Third Edition

:global.trans/2 is an Erlang function that acquires a distributed lock, executes a function, and releases the lock.

:global.trans/2 coordinates a cluster-wide critical section: it acquires a distributed lock, runs a function, and releases the lock afterward. A lock identifier such as {:some_resource, self()} distinguishes the requester; using a process ID allows at most one process to hold that lock. section 12.1.5

Serializing large-data processing

def process(large_data) do :global.trans( {:some_resource, self()}, fn -> do_something_with(large_data) end ) end This serializes the operation across the cluster without first sending the large data to a synchronization process. section 12.1.5

Use locks judiciously: excessive locking can produce deadlocks, livelocks, or starvation. Process-based synchronization is generally easier to reason about, while a lock can avoid the serialization, transmission, and copying costs of passing large messages between nodes. section 12.1.5

def process(large_data) do
  :global.trans(                     #1
    {:some_resource, self},
    fn ->
      do_something_with(large_data)  #2
    end
  )
end

View the runnable Elixir-shaped acquire, execute, and release pattern. section 12.1.5

How Elixir in Action, Third Edition covers it

How deep it goes
Explains lock identity, blocking acquisition, automatic release, and trade-offs without detailing lock internals.
Examples
Demonstrates serializing large-data processing across nodes with a resource key and process identifier.
What it assumes
Assumes familiarity with distributed nodes, processes, process identifiers, and function execution.
What you can do after
Apply it via :global.trans/2 to wrap a cluster-wide critical section and release its lock after execution.
How it connects
Connects distributed locks with processes, message passing, deadlocks, livelocks, starvation, and distributed systems.
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