Read-Only State | Teradata Business Continuity Manager - Read-Only State - Teradata Business Continuity Manager

Teradata® Business Continuity Manager User Guide - 2.00

Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
VMware
Product
Teradata Business Continuity Manager
Release Number
2.00
Published
August 2024
ft:locale
en-US
ft:lastEdition
2025-01-31
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sko1694443904278.ditamap
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dita:id
otc1639627713801
Product Category
Analytical Ecosystem

This state enables read access for an application when data is externally copied from the table and must remain unchanged.

For managed sessions, if a table is in a Read-Only state across all database systems, Business Continuity Manager rejects the write with an error. If only a single database system or a table on a specific database system is in Read-Only state, then any write requests remain queued in the Recovery Log to be replayed when the database system or table is placed into a Restore state.

If a database system enters a Read-Only state, all tables automatically enter a Read-Only state. If a table is read-only on one or more systems and a write occurs on this table (because the table is in read-write mode on at least one other active system), then the Read-Only state is changed to an Interrupted state.

A table may also automatically be placed in Read-Only state if a session encounters an error and the "Read-only on write failure" feature is turned on.

To change a table or system to a Read-Only state, run the SYSTEM FREEZE command. Business Continuity Manager holds any new transactions and waits for any in-flight transactions to close. The Dispatcher holds transactions for the time specified in the HaltTimeout parameter. If successful, the database system or table becomes read-only. If an error occurs or if in-flight transactions do not finish successfully during the timeout, the operation aborts and the database system or table remains in the Active state.

Use the SYSTEM RECOVER command to change a database system or table from the Read-Only state to a Restore state.