Region

Data Cache

EXCLUSIVE

When a task accesses a critical section, the associated region blocks this critical section for all other tasks.

Reader-writer lock

(share lock)

Catalog Cache

Shared SQL Cache

EXCLUSIVE or SHARED

If a task write-accesses a critical section, the associated reader-writer lock (share lock) blocks this critical section for all other write-accesses but allows other read-accesses.

If a task read-accesses a critical section, the associated reader-writer lock (share lock) blocks this critical section for all write-accesses but allows other read-accesses.