PNUTs, SCADS, Hive

Notes on Tyson's presentation about PNUTS:



• complaint: not enough control over replication
• predicate to system, apply to the system before
• hash or sorted tables
• no foreign key constraints (not normalized?)
  
• selection predicates, and projection from tables
  
• no joins
  
• per record timeline consistency, all replicas apply updates to record in same order. all updates go to a master, which moves around for performace
  
• tyson likes that they took the right pieces out of the db to support the right pieces (read one record at a time)
  
• no fine control over replication factor
  
• rethink isolation?

Notes on Michael's SCADS talk:


• Scale independence (borrowed idea from db papers, data independence)
• No changes to app as you scale
  
• latency stays constant
  
• const/users stays constant
• auto scale up/down
  
• declarative performance consistency
  
• perf. safe query language (cardinality constraints)
  
• give developers axis that they understand:
  
• performance SLA
• read consistency (freshness)
• write consistency
• durability SLA
• Session guarantees (monontonic reads, read your own writes)