Lazy Consistency Using Loosely Synchronized Clocks

Thispaperdescribesanewschemeforguaranteeingthattransactions in a client/server system observe consistent state while they are running. The scheme is presented in conjunction with an optimistic concurrency control algorithm, but could also be used to prevent read-only transactions from conflicting with read/write transactions in a multi-version system. The scheme is lazy about the consistency it provides for running transactions and also in the way it generates the consistency information. The paper presents results of simulation experiments showing that the cost of the scheme is negligible. The scheme uses multipart timestamps to inform nodes about information they need to know. Today the utility of such schemes is limited because timestamp size is proportional to system size and therefore the schemes don’t scale to very large systems. We show how to solve this problem. Our multipart timestamps are based on real rather than logical clocks; we assume clocks in the system are loosely...

• Type: Conference
• Year: 1997
• Where: PODC
• Authors: Atul Adya, Barbara Liskov
• Keywords: Distributed And Parallel Computing, Multipart Timestamps, Observe Consistent State, Optimistic Concurrency Control, PODC 1997