By Sezgi GECER on Mar 24, 2013
Hello all, In this post we will present an issue, we faced a few weeks ago, when one of our customers run annual job batches on Exadata. During those operations they realized that 'Insert as select (IAS)' was dramatically slower than 'Create table as select (CTAS)' for the same tables and application. There was a really huge difference on duration between them, whilst CTAS was taking 40 seconds, IAS took almost 6 minutes!
We've checked the execution plans of those queries and saw that CTAS was doing Smart Scan, it's wait event was "cell smart table scan" and Cell Offload Effiency %91 but IAS was not doing ![Read More]