#10 - Latching in Data Structures

The issue we're solving

Is the internal representation of an object "sound" - eg. no pointers pointing to where object was, not is, no segfaults, and so on. What's not covered - the logical (business logic) or correctness (read your writes, Linearizability, Causal Consistency). We use word "latches" for former (think workers/threads). And we use locks for latter (think transactions)

Latches are used to protect our in-memory datastructures, workers might require to rollback changes if they can't acquire latches. We won't have a top-view supervisor which keeps track of all workers, therefore each worker needs to self-encapsulate logic on what do when it can't get a latch. And we need that logic to not be blocking and not require deadlock detection & resolution.

Latch implementation goals

Small memory footprint
Fast execution path when no contention
Decentralized management of latches (as mentioned above)
Avoid expensive syscalls