12c Parallel Execution New Features: Hybrid Hash Distribution - Part 1
In this blog post I want to cover some aspects of the the new HYBRID HASH adaptive distribution method that I haven't covered yet in my other posts.As far as I know it serves two purposes for parallel...
View Article12c Parallel Execution New Features: Hybrid Hash Distribution - Part 2
In the second part of this post (go to part 1) I want to focus on the hybrid distribution for skewed join expressions.2. Hybrid Distribution For Skewed Join ExpressionsThe HYBRID HASH distribution...
View Article12c Parallel Execution New Features: Concurrent UNION ALL - Part 1
12c introduces the concurrent UNION ALL operator that allows multiple branches below the UNION ALL to become active concurrently - which is a significant change. Before the introduction of this feature...
View Article12c Parallel Execution New Features: Concurrent UNION ALL - Part 2
In the first part of this series I've focused on the parallel degree chosen by the optimizer when dealing with the new concurrent UNION ALL feature.I've shown that for the variant with serial branches...
View Article12c Parallel Execution New Features: Concurrent UNION ALL - Part 3
In the final part of this instalment I want to focus on the possible optimisation of remote access that I outlined in the initial part, which is based on the idea of running multiple concurrent remote...
View Article12c Parallel Execution New Features: PX SELECTOR
Continuing my series on new 12c Parallel Execution features: I've already mentioned the new PX SELECTOR operator as part of the new Concurrent UNION ALL feature where it plays a key role.read more
View Article12c Parallel Execution New Features: 1 SLAVE distribution
When certain SQL features get used in pre-12c versions that force non-parallel evaluation, like using ROWNUM or certain Analytic Functions like LAG/LEAD, then - depending on the overall plan shape -...
View Article12c Parallel Execution New Features: Parallel FILTER Subquery Evaluation -...
12c introduces another interesting new Parallel Execution feature - the parallel evaluation of FILTER subqueries. In pre-12c FILTER subqueries always had to be evaluated in the Query Coordinator. This...
View Article12c Parallel Execution New Features: Parallel FILTER Subquery Evaluation -...
Picking up from the first part of this instalment I'll focus in this post on the available distribution methods for the new parallel FILTER subquery feature.In this post I won't go into the details how...
View Article12c Parallel Execution New Features: Parallel FILTER Subquery Evaluation -...
As mentioned in the first and second part of this instalment the different available distribution methods of the new parallel FILTER are selected automatically by the optimizer - in this last post of...
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