Ensuring consistency when multiple users access data across sites requires sophisticated locking and ordering mechanisms. Locking and Timestamping
Good for clusters but suffers from communication overhead.
How do we ensure that a transaction either commits at every site or aborts at every site? The 2PC Protocol Ensuring consistency when multiple users access data across
Replacing global relations with their fragments.
The coordinator asks participants if they are ready to commit. The 2PC Protocol Replacing global relations with their
Query processing solutions typically follow a four-step process:
Solution Tip: This leads to a "blocked" state. Participants cannot decide on their own because they don't know the global outcome, highlighting a major weakness of basic 2PC (the need for 3PC or recovery protocols). 5. Parallel Database Systems Participants cannot decide on their own because they
Problem: Calculate the cost of a join between two tables located at different sites using a .
Data isn't unnecessarily duplicated (unless specifically replicated for availability).