Welcome to the dbi services Blog! This blog focuses on IT infrastructure - featuring news, troubleshooting, and tips & tricks. It covers database, middleware, and OS technologies such as Oracle, Microsoft SQL Server, Documentum, MySQL, PostgreSQL, Sybase, Unix/Linux, etc. The dbi services blog represents the view of our consultants, not necessarily that of dbi services. Feel free to comment on the postings!
Hervé Schweitzer is Chief Technology Officer (CTO) and Principal Consultant at dbi services. He has more than ten years of experience in database and infrastructure management, engineering, and optimization. He is specialized in Oracle technologies such as standardisation, Backup and Recovery, Tuning, and in High Availability solutions such as Oracle Data Guard, Oracle Grid Infrastructure, Oracle Real Application Clusters (RAC), Oracle GoldenGate, and Oracle Failsafe. Hervé Schweitzer is Oracle Certified Master 11g (OCM 11g). Prior to joining dbi services, Hervé Schweitzer was Senior Consultant at Trivadis in Basel. He also worked as an IT Administrator and Oracle DBA at Crossair in Basel. Hervé Schweitzer holds a BTS degree in Information Systems from France. His branch-related experience covers Pharma, Transport and Logistics, Banking, Energy, Automotive etc.
Last week, I attended the Microsoft TechDays for the first time. The Swiss 2011 "edition" took place in Bern. For me this is really a new challenge because I have never worked deeply with the Microsoft database platform "SQL Server".
While discussing with some tuning gurus, I was made aware about this feature. It is not so far from the adaptive cursor sharing perfectly described in Chris Antognini'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.
Recently, at a customer site, I had an Oracle Data Pump error 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
Perhaps you know this situation: A developper or application owner quickly needs a test database to test new code or to validate changed code before implementing it. Sounds like a lot of work, but if you have Data Guard 11g, you can simply use the command "CONVERT TO SNAPSHOT STANDBY".