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ORA-01555 caused by SQL statement below… on Active Dataguard after upgrade to 25 January 2011

Posted by David Alejo Marcos in Oracle 11.2, Standby, Tuning.
Tags: , ,

Sometimes I wonder why we do upgrade our databases…

The problem:

after upgrading from to, our standby databases (we are using active dataguard) was recording ORA-01555 on the alert log file after being running for some time.

We actively use our standby databases to run some queries for reporting.

The solution:

We have two standby databases, one local (less than 50km away) and another one on a remote location (250km) from primary.

The first thing we did was to raise a ticket with Oracle and change one of the standby databases from “open read only” to “mounted” (I had experience with problems on active dataguard in the past).

This proved useful in several ways:

1.- We narrowed the problem to active dataguard. The database in mount status was applying log files without issues and not logging any errors. The other standby started to log errors after a few hours of running (seems time depends on the workload the database is under).

2.- Once we stop the database and open it in read only, it will work for some time (not very elegant but still useful).

3.- Oracle Support came with a bug and a fix.

The bug number is 10320455 and the new patch is 10018789 (to be applied on top of

The problem itself seems to be a hang (lock) in the library cache. This lock will cause the workload to accumulate and do not release resources and logging ORA-01555 after some time.

As the patch only updates binaries (546 kb in size) we might apply it to DR and, once we secure some downtime over the weekend, apply it to production. This will help us to minimize the time we impact business by having the standby databases in mounted status.

As always, comments are welcome.


1. radhakrishna - 26 January 2011

is it possible to use 11g r2 databases with 10g r2 ASM instance

David Alejo Marcos - 5 February 2011

Good morning,

An Oracle ASM instance must be 11gR2 to be able to support an Oracle 11gR2 database.

Thank you.

David Alejo Marcos.

2. José Antonio de Pablo - 7 February 2011

I think we are in the same status that you… We are in the “Open SR” status.
But we are in that status tanks to your post, so THANK YOU very much.

José Antonio de Pablo - 7 February 2011

Sorry. I was meaning that we are in the same problem with read-only standby with real time apply.

David Alejo Marcos - 8 February 2011

Thank you Jose Antonio,

Applying the patch listed on my “solution” did the job for us and we are not seeing the error anymore on the standby databases.


David Alejo-Marcos.

3. Younus Siddiqui - 19 July 2011

We have same issue but with Our SR has been open since May 15th, first as Sev1 and now in escalated sev2 status.

I am told development is working on bug fix.

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