In a shared-nothing parallel computer each processor has its own
memory and disks and processors communicate by passing messages
through an interconnect. Many academic researchers and some vendors
assert that shared-nothingness is the consensus architecture for
parallel DBMSs. This alleged consensus is used as a justification for
simulation models, algorithms, research prototypes and even marketing
campaigns. We argue that shared-nothingness is no longer the consensus
hardware architecture and that hardware resource sharing is a poor
basis for categorising parallel DBMS software architectures if one
wishes to compare the performance characteristics of parallel DBMS
products.