Exadata

RMAN channels in RAC

By Franck Pachot . When you want to minimize the backup or restore duration, you can parallelize RMAN operations by allocating multiple channels. If you are in cluster, you can open channels from several nodes. Let's see why, how, and(…)

Oracle and Analytic Queries before In-Memory option

By Franck Pachot . Next Tuesday in Geneva I'm presenting Oracle In-Memory Column Store to Business Intelligence people at the Swiss BI Day After defining what is an analytic query, I show the different approaches to optimize that in(…)

Never gather WORKLOAD stats on Exadata…

By Franck Pachot . For Exadata, oracle has introduced an ‘EXADATA’ mode which sets a high transfer rate (with IOTFRSPEED as in NOWORKLOAD statistics) and set a MBRC (as in WORKLOAD statistics). Those values are set rather than gathered(…)

How to measure Exadata SmartScan efficiency

By Franck Pachot . A thread on OTN Forum about Exadata came to the following question: “But how can I monitor if it is effectively used or not?”. This is a common question. There are 3 exclusive features coming(…)

Oracle Exadata – poor optimization for FIRST_ROWS

By Franck Pachot . In a previous blog, I discussed the difference between rownum and row_number(), in particular their behaviour in implicitely adding a first_rows(n) to the optimizer. That reminded me that I forgot to blog about an(…)

Oracle Database Appliance (ODA) – an overview

Last february, I had the chance to attend an Oracle presentation about ODA: Oracle Database Appliance. I found it interessant to share what I have learned about this technology. Which, I confess, convinced me. Summary Before developing the software(…)