ORA-01578 after rman recovery

-
Oracle - 11.2

This is a brief list pointing out some factors on nologging operations which results unrecoverability in database. Once a db backup with unrecoverable operations fully recovered, accessing affected objects will still return ORA--1578.

1. Detecting unrecoverable operations.

Rman "report unrecoverable" will provide list of datafiles which are in unrecoverable state.

Also unrecoverable_time column of v$datafile can be queried to see the last unrecoverable action performed on particular datafile, but this column will not be updated after a backup is made from rman.

2. There want be any errors during the restore/recovery operations in rman  logs.

Even during a nologging operation small amount of redo is generated. These logs simply says that affected block is for nologging operation. So during a roll-forward these logs will be applied, but they will logically corrupt the affected blocks.

3. After full restore/recovery of daabase with nologging corrupted blockes you will still not see these blocks reported in v$database_block_corruption unless "VALIDATE CHECK LOGICAL DATABASE" is executed from rman to logically validate the database.

4. Nologgin corruption can not be recovered using archive logs. Because the only log recorded for nologging operations says that "This block related to nologging operation".

So if it is a table or table partition it need to be reloaded from flat file or imported from dump file. If it is a index it needs to be rebuild.

Comments

Post a Comment

Popular posts from this blog

ORA-16433: The database or pluggable database must be opened in read/write

-
Image
ORA-16433 is an error returned when a database cannot be opened. This can be a result of multiple conditions including, The inconsistency of the database Physical corruption Loss of dependent files or access issues etc.. More often than not the solution is to recover from available backups, but there can be situations where backups are not available, specially on UAT or Test setups. Although not the ideal scenario, in this type of situation you might want to open the databases even with inconsistency.  In Comes --> _ALLOW_RESETLOGS_CORRUPTION First, if you are in a position to use _ALLOW_RESETLOGS_CORRUPTION=TRUE, that means it has to be a critical moment, and when you come across more ora- errors while you are trying to reopen the databsae, that can be annoying. Note - _ALLOW_RESETLOGS_CORRUPTION=TRUE must only be used after Oracle support confirmation as a last resort. Also make sure to take cold backup before proceeding. Basic steps to be followed to resolve ORA 16433 after
Read more

Oracle Multitenant - Create new service for PDB using DBMS_SERVICE

-
Image
When an Oracle PDB is created it starts up a default service with the PDB name. For direct connections to    PDB this service can be used. But there are situations where new service name is required in PDB level, common example is after a PDB restoration/clone, in order to enable application connections without changes in connection string. Setting service_names parameter in PDB level is not possible hence it is not an option in multitenant setup. How to create a new PDB service on Oracle 12C Check the current services, here only the default service is running, SQL> show pdbs; CON_ID CON_NAME OPEN MODE RESTRICTED ---------- ------------------------------ ---------- ---------- 3 NFACTORPDB READ WRITE NO SQL> select service_id, name, pdb from dba_Services; SERVICE_ID NAME PDB ---------- ---------------------------------------- ---------- 7 nfactorpdb NFACTORPDB SQL> Create
Read more

Wait for unread message on broadcast channel - Blocking Sessions

-
Image
What is Wait for unread message on broadcast channel wait event? Wait for unread message on broadcast channel is a wait event where source destination communication is involved and the database is waiting for a reply from remote party. Mostly this wait is seen related to data pump export (expdp) or import (impdp) operations. Although categorized in idle wait class "Wait for unread message on broadcast channel" can become the blocking session for some other sessions. Common causes for stuck sessions waiting on this wait event includes, Broken databases links, where remote database is not responding. Abnormally killed remote processes causing the sessions to wait. When a session is waiting on "Wait for unread message on broadcast channel" it can become a blocking session for dependent sessions. Most probably these sessions will be waiting on "library cache pin" or related concurrency wait events. The blocking_session column of (g)v$session view
Read more