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Hervé Schweitzer

Hervé Schweitzer

RMAN backup is failing due to “corrupt blocks”

By | Hardware & Storage | No Comments

Last week, I was not able to complete a backup because of the ORA-19566 error: “exceeded limit of 0 corrupt blocks”. Here is what you can do to fix it. Starting Point: backup error Here is the starting point of this case. The following error is found in the RMAN Backup log file: allocated channel: ch1 channel ch1: sid=25 devtype=DISK Starting backup at 27-APR-11 channel ch1: starting incremental level 0 datafile backupset channel ch1: specifying…

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Hervé Schweitzer

A SQL statement is slow and suddenly fast? Have a look at “Cardinality Feedback”!

By | Application integration & Middleware | 2 Comments

Discussing with some tuning gourous we were made aware about this feature. It is not so far from the adaptive cursor sharing perfectly described in  Chris’s blog : http://antognini.ch/papers/BindVariablePeeking_20090718.pdf

This feature, compares the real execution (number of returned/actual rows “A-rows”) with some expectations (number of expected rows “E-rows”) and chooses another plan for the next executions if the difference between the expectation and the actual result is too big. “Cardinality Feedback” is not well documented in the Oracle documentation.

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Hervé Schweitzer

How to debug a Data Pump error

By | Database management | One Comment

Recently, I had an Oracle error with Data Pump at a Customer, which was not easy to localize. Here is the error I received during a DBIOWNER schema export with Data Pump:

Processing object type SCHEMA_EXPORT/TABLE/STATISTICS/TABLE_STATISTICS
ORA-39125: Worker unexpected fatal error in KUPW$WORKER.UNLOAD_METADATA while calling DBMS_METADATA.FETCH_XML_CLOB [TABLE_STATISTICS]
ORA-00942: table or view does not exist

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