Also called: lock table partition, lock manager partition, NUM_LOCK_PARTITIONS
In plain English
The shared lock table is divided into 16 partitions, each protected by its own lightweight lock and chosen by a hash of the lock tag. Splitting it this way means two backends locking different objects usually touch different partitions and don’t contend with each other on the same internal lock.
Why it matters
Partitioning is what keeps the shared lock table scalable — but it only helps when locks spread across partitions. A workload that overflows the fast-path and funnels many locks into the shared table can still create partition-lock contention, which is why reducing the number of locked relations (partition pruning) matters.