Blocked Processes

Comments

When a process must wait to acquire a lock, it is a waiter. The other process that already has the lock (and is causing the waiter to wait) is a blocker.

This view contains rows for both the blocker processes and the waiter processes in the database. If the row is a blocker process, then BLOCKER = 0. If the row is a waiter process, then the BLOCKER column has information about its immediate blocker.

Waiters being blocked by a blocker can themselves also block other waiters, potentially forming a blocktree involving many processes. Thus, a row can be a waiter and a blocker, in some cases (and can involve different locks).

Columns

Entity Requirements

Sample