Yes, direct path reads again :)
No worries I’m already a bit bored from digging in this algorithm, so I think this is going to be my last post about it. Till they change it again of course. And yes, in 22.214.171.124 they did.
HROUG,SIOUG and BGOUG.
At HROUG and SIOUG I’ll be speaking for Exadata and at BGOUG, maybe for near zero downtime migration or some similar geeky topic ;)
Links to the events:
In Oracle Database 12c we can find many new and shiny things… So many that we can miss the little good things really easy. I think this one, is one of them.
Today while I was scrolling my “WordPress reader” page I saw a post which reminds me to something I had fun before /and find it useful in many situations/:
As simple as that!
A fast and straight approach for creating local IPS repository.
Most people are relating direct path reads with an algorithm which is just controlling the way our read is performed. But actually in Exadata environment this is the algorithm which is balancing the load between the Compute and the Storage nodes. Something really important.
As usual, the algorithm is not perfect and for some situations we shall be able to control it.
In here we’ll cover the flowing parameters:
Each parameter have its own “charm” and reason to be here.
If you try to find out what is HCC and how it works you could start reading the documentation, then some books, blog posts and at the end you will have to put all together. In this post I’ll do exactly this. Put all together. Starting with the basic and going through the internals with examples.
HCC stands for Hybrid Columnar Compression. This is the kick ass compression of Oracle Database, which can provide you up to 15x compression ratio. It can be used only on SPARC SuperCLuster,Exadata,Pillar Axiom and ZFSSA.
Well, that was the marketing part. Now let see how it works.