Locking - Teradata Meta Data Services

Teradata Meta Data Services Programmer Guide

Teradata Meta Data Services
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Teradata Tools and Utilities


A locking protocol is necessary to guarantee the standard ACID properties of transactions (atomicity, consistency, isolation, and durability) when multiple concurrent transactions are being processed against the MDS repository (for example, when there are multiple active MDS application processes). The Teradata Database System automatically handles all issues related to locking for transaction management, including read locking, write locking, prioritizing, and queuing lock requests, upgrading locks, and releasing locks.

Teradata also automatically detects and resolves deadlocks at the database level. Each MDS application processes only one transaction at a time, so there is no possibility of a local deadlock inside an MDS process.

MDS does not allow users to read repository information that is write locked by another transaction as doing so could return inconsistent data.