Using the Lock Manager to Choose Timestamps

Our goal is to support transaction-time functionality that enables the coexistence of ordinary, non-temporal tables with transaction-time tables. In such a system, each transaction updating a transaction-time or snapshot table must include a timestamp for its updated data that correctly reflects the serialization order of the transactions, including transactions on ordinary tables. A serious issue is coping with SQL CURRENT_TIME functions, which should return a time consistent with a transaction’s timestamp and serialization order. Prior timestamping techniques cannot support such functions with this desired semantics. We show how to compatibly extend conventional database functionality for transactiontime support by exploiting the database system lock manager and by utilizing a spectrum of optimizations.

• Type: Conference
• Year: 2005
• Where: IDEAS
• Authors: David B. Lomet, Richard T. Snodgrass, Christian S. Jensen
• Keywords: Database, IDEAS 2005, Serialization Order, SQL CURRENT_TIME Functions, Transaction’s Timestamp