Issue

Parameter _rollback_segment_count can cause trouble

Just some weeks ago we’ve learned that setting the hidden underscore parameter:

_rollback_segment_count

may cause trouble during upgrade. This parameter is used in very rare cases to have under all circumstances and situations this specified number of UNDO’s online. Now during upgrade this may result in massive latch contention  – and there’s a patch available as well. Recommendation is to unset it during upgrade.

I don’t think that many people will hit this as I personally haven’t seen databases with this underscore in their init.ora or spfiles. So take this post more or less as a reminder …

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Ouch … again OCM

Another customer, another upgrade – and again from Oracle Database 11.1.0.7 to Oracle Database 11.2.0.3. And again an OCM error during upgrade which is not very obvious to relate to OCM once you see the errors during upgrade.

While monitoring the database during upgrade with tail -f on the alert.log we’ve spotted this one here:

ORA-604: error occurred at recursive SQL level 3
ORA-904: "XDB"."DBMS_CSX_INT"."GUIDTO32": invalid identifier
XDB SGA reset to NULL.

Looks like some issue with XDB. But actually it is related to OCM and it seems that something gets created in the wrong order. Currently DEV is working …

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Upgrade to 11.2.0.3 – OCM: ORA-12012 and ORA-29280

OCM is the Oracle Configuration Manager, a tool to proactively monitor your Oracle environment to provide this information to Oracle Software Support. As OCM is installed by default in many databases but is some sort of independent from the database’s version you won’t expect any issues during or after a database upgrade 😉

But after the upgrade from Oracle 11.1.0.7 to Oracle 11.2.0.3 on Exadata X2-2 one of my customers found the following error in the alert.log every 24 hours:

Errors in file /opt/oracle/diag/rdbms/db/trace/db_j001_26027.trc:
ORA-12012: error on auto execute of job "ORACLE_OCM"."MGMT_CONFIG_JOB_2_1"
ORA-29280: invalid directory path
ORA-06512: at "ORACLE_OCM.MGMT_DB_LL_METRICS", 
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Fundamental Oracle flaw revealed??? Update …!

Writing a blog has a nice effect on the side: it brings me in touch with people I’ve never met – but we have similar targets or interests. Today I’ve received a comment from Gökhan Atil about the Fundamental Oracle Flaw known also as the SCN issue.

And for sure I did visit Gökhan’s blog and I did watch his very interesting 5 minutes demonstration how to bring down a database with the SCN issue. Which is very good to know as I thought the database won’t come down because of this issue. But watch Gökhan’s video by …

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