Principles — Of Distributed Database Systems Exercise Solutions

). Minterm predicates are conjunctions (AND operations) of every primitive predicate or its negation.

Upon receiving acknowledgments ( ACK ) from all participants, it writes an End record to its log. The coordinator asks participants if they are ready

The coordinator asks participants if they are ready to commit. Assume this reduces by 80%, leaving 2,000 matching tuples

Cost=1,000×200 bytes=200,000 bytesCost equals 1 comma 000 cross 200 bytes equals 200 comma 000 bytes Send the projection from Site 2 to Site 1. Assume this reduces by 80%

Cost1=Unique keys of S[A]×Size of A=500×10=5,000 bytesCost sub 1 equals Unique keys of cap S open bracket cap A close bracket cross Size of cap A equals 500 cross 10 equals 5 comma 000 bytes Compute the semi-join locally at Site 1. Assume this reduces by 80%, leaving 2,000 matching tuples. Ship the reduced relation R′cap R prime from Site 1 to Site 2.

. A common exercise involves detecting "Global Deadlock" using a Distributed Wait-For Graph. Reliability & 2-Phase Commit (2PC):