Technical Thoughts

Overview Sql Plan Directives(SPD) got introduced in 12.1.0.1 and its main objective is to take corrective action or help the Optimizer whenever there is misestimation of cardinality, this help Optimizer to generate more optimal plan. SPD are created at table/column/predicate level so that it can be used by any sql...

Introduction In previous article we discussed about 12c new feature Adaptive plans related to Join Methods, in this article we will discuss about Adaptive plans related to Parallel Distribution Methods. Usually when parallel sql statements are executed then Optimizer has to decide on the distribution method for the parallel processes...

Introduction Adaptive Plans is one of the new feature in introduced in 12c and is part of Adaptive Query Optimization feature. Adaptive Plans can be further categorized into two methods as Join method and Parallel distribution methods. In this article we will focus only on Adaptive Join method. Adaptive Join...

Objective was to perform root cause analysis for a batch job which had degradation in performance. Usually it becomes more strenuous when we are assinged to work on a issue which had occurred in past. But still its going to be interesting and challening work to drill down onto the...

Concept Consistent read is one of the main concept among the ACID properties provided by Oracle. The one which supports this Consistency is UNDO in Oracle. But according to concepts of Exadata, cell/storage servers doesn’t communicate each other and thus constructing the consistent image of the database blocks by using...