Archive for September, 2013

Oracle 12c: Change hostname for Grid Infrastructure / Oracle restart

Few days ago, we cloned a VM test system with ASM. Changing the hostname in this case is mandatory from our network, we have lots of issues if they are duplicate.

But changing an Oracle Restart or generally, Grid Infrastructure setup’s hostname isn’t so easy – it’s written many configs. The only way is to deconfigure and configure the Grid Infrastructure stack. If you have no special services configured, it’s quite straightforward, as my colleague Benedikt Nahlovsky describes.

If there are additional / self-made services, just recreate them with your scripts (don’t forget to change the hostname in them if you used it!)

Hope you are doing well
Martin Klier

By Martin Klier in Oracle  .::. (Add your comment)

Oracle 12c New Features – Look at’s for

A new product …

Last week I spent some days of intense investigation and testing the new database 12c. I found lots of great stuff (even about 11g :) ), and some for sure will make it into a separate blog post. So these are just my notes of a very interesting couple of days, and maybe it can be a guide for you when starting to dive deeper into the newest RDBMS coming from Redwood Shores. Just let me know your opinion, and maybe submit a comment.

Unfortunately, many of the new features are only available in Enterprise Edition or EE plus some options or additional products. As far as I knew the need, I marked my points accordingly. But don’t rely on my information, have a look at the most recent licensing guide!

One word before we start: Do nothing before you know WHAT you do. And with a new Oracle product, you CAN’T know what you do yet. So play happily, but don’t use it in production until second PSU or first patch set and its first PSU.

Oracle Database 12c Architecture

  • PROCESSOR_GROUP_NAME parameter — allows to bind the instance to a Linux CGROUP, it’s NUMA aware
  • THREADED_EXECUTION parameter — Enables Multithreaded Architecture (MTA), intended to speed up internal work and saves process spawning. No OS authentication allowed, need to use the password file (thus, “sqlplus / as sysdba” and “rman target /” do not work any more)
  • USE_DEDICATED_BROKER parameter — use threads, not dedicated servers
  • v$process STID column — holds reference to the system thread in multithreaded architecture
  • DEDICATED_THROUGH_BROKER_[LISTENERNAME] listener parameter — make the listener spawn threads, not dedicated servers
  • To be done: Investigate serialization waits in MTA vs. conventional process architecture
  • Smart Flash Cache allows more than one device — possible to deactivate one at runtime; if two, one is used for OLTP, one for OLAP (distinction by Parallel Execution)
  • SDU (Session Data Unit) of TNS allows max. 2MB — calculate 70 bytes of overhead per packet; use “trcasst -t” utility;

Generic Database Administration

  • catupgrd.sql deprecated — use now
  • DBMS_QOPATCH — query opatch information within RDBMS
  • DBMS_SCHEDULER now has a RMAN job type
  • option_usage.sql and used_option_details.sql scripts — from My Oracle Support (ID 1317265.1) for license-relevant infos
  • STATSPACK enriched with PDB awareness — but always install it into the PDB, not into the CDB
  • ADRCI improved — some menus allow interactive HOME selection (SHOW CONTROL does not)
  • varchar2(32k) / nvarchar2(32k) — are just LOBs, with all limitations (no ORDER BY / GROUP BY)

Multitenant Database

Read more…

By Martin Klier in Oracle  .::. Read Comments (2)

DOAG Konferenz 2013: “Oracle Architektur – nicht nur für Einsteiger”





After speaking about mutex waits last year, this time DOAG accepted my lecture “Oracle Architektur – nicht nur für Einsteiger” about Oracle Database basic architecture for this year’s DOAG Konferenz 2013 in Nürnberg. It will be the first lesson in a brand-new stream of the conference: The so-called “Einsteigerpaket” (beginners package) allows seeing a full stream of introductory talks by only purchasing a one-day ticket for the last day (thursday).

“Oracle Architektur – nicht nur für Einsteiger” will cover basic but important concepts of the Oracle RDBMS: How it makes ACID happen, what are Redo Logs, Undo Records, Before Images, how is locking done, and where not, and why all of those old day’s features allowed Oracle to introduce sophisticated stuff like RAC, Dataguard and Flashback without breaking bones.

Nuts and bolts is the topic, but on a level every IT technican should understand. Hope to see you there: 21.11.2013, 0900h, Room 19

Direct link to the session:

Here the link to the papers and a photo from the session.

By Martin Klier in Community,DOAG,Lectures,Oracle  .::. (Add your comment)

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