6 Overview | Nortel Networks Confidential |
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while the secondary database operates in a limited write state at all times.
Table 1 Database operational states
Database states | Description |
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Normal | Fully writable for applications. Inserts, |
(Primary database) | updates, or deletions are permitted to the |
| primary database. The Oracle Server |
| continuously transfers changed data to the |
| secondary database. |
Limited write (Secondary database)
Quiesced (maintenance mode)
Read only for applications with the exception of registrations (inserts, updates, or deletions).
In the unlikely event of failure of the primary database, applications failover to the secondary database. During failover, applications can read and have limited write access to the secondary database. The failover state continues only until the primary database returns to service.
Note: The secondary database operates in a limited write state for applications but is always fully writable for Oracle replication processes.
No writes are permitted to either database.
When the database is quiesced, applications can only query the database and cannot insert, update, or delete database records.
Replicated databases automatically enter this state whenever changes are being made to the replication environment, including modifying replication objects and synchronizing the two databases.
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