Friday Apr 24, 2015

In-Memory Priority

I'd like to thank everyone who attended our two Hands On Lab sessions at Collaborate last week. We had a great time presenting them and we received some really good feedback. One of the questions that came up, and gets asked periodically, is how does In-Memory priority really work?

Many times people have the misconception that the In-Memory priority attribute affects more than just the order of population but that’s not the case. The only thing the priority affects is the order of population at database startup. We discussed population briefly some time ago, but I think it's worth a quick review.

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Monday Apr 20, 2015

Oracle Database In-Memory Bundle Patch 7 Released

In one of my very first blog posts on Oracle Database In-Memory, I made reference to the fact that we would be releasing regular bundle patches for Oracle Database In-Memory. These bundle patches are available periodically through My Oracle Support.

The latest bundle patch to be released was bundle patch 7 or 12.1.0.2.7 (DATABASE PATCH FOR ENGINEERED SYSTEMS AND DB IN-MEMORY 12.1.0.2.7. More information on the latest bundle patch can be found in the MOS note, Doc ID 20698050.8.

The bundle patches are cumulative, which means bundle patch 7 includes all fixes from bundle patch 1 to 6 in addition to new content. Don't let the name of the bundle patch fool you. You can apply this bundle patch on non-engineered systems running Oracle Database In-Memory.

Going forward, we will keep you posted when a new bundle patch is released, so you will always know what is the latest bundle patch. We recommend that you always run with the latest bundle patch.

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Friday Apr 17, 2015

CPU Efficient Query Processing with Database In-Memory

In my last post I talked about In-Memory Aggregation and mentioned that the vector transformation plan is more CPU efficient than alternative plans. In this post I’ll provide a few examples to illustrate just how effective a vector transformation plan can be.

Let’s consider a star schema, with one fact table and 9 dimension tables (time, customer, product, channel and demographic attributes such as age and income).

9 Dimensional Star

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Thursday Apr 09, 2015

Push-Down: Part 2

In our previous post we introduced the concept of push down. The ability to push predicates, aggregations and group-bys down into the scan of a column or columns, allowing Oracle to take full advantage of all the scan performance features of the In-Memory column store. We also illustrated how you could monitor the benefits of push down via session level statistics (v$mystat). What you might not have realized is that we can also see what where clause predicates get push via the execution plan.

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Tuesday Mar 31, 2015

Push-Down: Making Queries Fast!

In our previous posts we discussed the basic architecture of the In-Memory column store (IM column store) and now we want to drill down into some of the unique performance enhancing features. Push-down is one of the optimizations that makes scanning columns in the IM column store very efficient. Oracle Database In-Memory has the ability to push predicates, aggregations and group-bys down into the scan of a column or columns.  This ability to push-down allows us to take advantage of other performance enhancing features of Database In-Memory like SIMD vector processing and storage indexes.

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Monday Feb 16, 2015

Getting started with Oracle Database In-Memory Part V - Aggregation

When most people think about Oracle Database In-Memory (Database In-Memory), the first thing that comes to mind is super fast scanning and filtering operations. But what you may not know is Database In-Memory also includes many SQL optimizations designed to accelerate star and snowflake type queries. We refer to this collection of SQL optimizations as In-Memory Aggregation (IMA). IMA is typically 3-10x faster than ‘conventional’ plans, and that’s in addition to the improvements provided by scanning and filtering the data via the In-Memory column store (IM column store).

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The Oracle Database In-Memory blog is written by the Oracle product management team and sheds light on all things In-Memory.

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