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12c

Some new Oracle Database 12c Articles

I’ve recently put some new Oracle 12c articles on the website.

The privilege usage stuff is really cool. Normally, trying to figure out what you can remove from a user is always a complete pain in the ass. Some of the databases I’m currently working with have used GRANT like it’s going out of fashion. Trying to identify what is really necessary is a tough job. Features like this are going to be hard to wait for…

Cheers

Tim…

 

Indexing Foreign Key Constraints With Invisible Indexes (Invisible People)

In my previous post I discussed when deleting rows from parent tables, how Bitmap Indexes based on the FK constraint can prevent the expensive Full Tables Scans (FTS) on the child tables but not the associated exclusive table locks. Last year, I discussed how it was possible in Oracle Database 12c to have multiple indexes on the same column list. […]

Running scripts in CDBs and PDBs in Oracle Database 12c

You’ve been sold on the whole concept of the multitenant option in Oracle 12c and you are launching full steam ahead. Your first database gets upgraded and converted to a PDB, so you start testing your shell scripts and bang! Broken! Your company uses CRON and shell scripting all over the place and the multitenant architecture has just gone and broken the lot in one fell swoop! I think this will end up being a big shock to many people.

12c Temporary

Just one of those little snippets to cover something new and remind of something old. A single session can now have three (or more) temporary tablespaces in use at the same time for different reasons.

12c Temporary

Just one of those little snippets to cover something new and remind of something old. A single session can now have three (or more) temporary tablespaces in use at the same time for different reasons.

12c pq_replicate

Another day, another airport lounge – another quick note: one of the changes that appeared in 12c was a tweak to the “broadcast” distribution option of parallel queries. I mentioned this in a footnote to a longer article a couple of months ago; this note simply expands on that brief comment with an example. We’ll start with a simple two-table hash join – which I’ll first construct and demonstrate in 11.2.0.4:

Dynamic Resource Mastering in 12c

I blogged about Dynamic Resource Mastering (DRM) in RAC here . DRM freezes the global resources during the reconfiguration event and no new resources can be allocated during the reconfiguration. This freeze has a dramatic effect of inducing huge amount of waits for gc buffer busy [acquire|release] events and other gcs drm freeze release, gcs remaster events. In database version 12c, DRM has been improved further.

A major improvement I see is that not all resources are frozen at any time. Essentially, resources are broken down in to partitions and only a resource partition is frozen. This improvement should decrease the impact of DRM related waits tremendously.

LMON Trace file

Modify Primary Key Using Index (Learning To Fly)

One of the things I love about working with Oracle Database technologies is that there’s just so much one can learn. I make it an active goal of mine to try to learn something new at work each and every day, no matter how big or small. One of these days, I might blog about a presentation I put together […]

Hotsos 2014

I will be presenting in HOTSOS symposium 2014 discussing correct methods to diagnose RAC performance issues. Very surprisingly, even very senior performance engineers make mistakes in their analysis while reviewing RAC issues. Come to my presentation and learn the golden rules of RAC performance diagnostics.

RAC and Pluggable Databases

In preparation of the OUGN Spring Seminar and to finally fulfill at least a part of my promise from July I was getting ready to research RAC, PDBs and services for my demos. It turned out to become a lot more interesting than I first assumed.

RAC and Multi-Tenancy

So the first attempt to really look at how this works has started with my 2 node cluster where I created a RAC database: RAC12C, administrator managed with instance RAC12C1 and RAC12C2. The database is registered in Clusterware. Clusterware and RDBMS are patched to the January PSU, i.e. 12.1.0.1.2.