Friday Philosophy – Do Average to Be a Success

A few days ago a friend of mine, helifromfinland, tweeted something that exactly matched the topic that I was thinking of doing my next Friday Philosophy on. Heli said:

I am learning to do things well enough, not always perfect. Even writing that sentence feels so wrong but #babysteps :-D

That made me smile – I know the feeling myself and I know some people for whom it is all-consuming. It is something that I (more...)

Optimizing working environment. Part I, GUI

Working with database performance troubleshooting means dealing with challenging and exciting problems. But it also means doing certain things over and over. And over. Like typing the same query or clicking the same button zillion times a day. And when you’re doing something very frequently, anything that can be done to simplify or automate such tasks becomes very important. So I decided to share some of the tricks I use to optimize my working experience in (more...)

x$bh and consistency

Oracle caches the data blocks in buffer cache in various modes depends on the block usage.  As per the Oracle documentation it can CR (Consistent mode – reads), XCUR (Current mode – updates), FREE etc.   I understand and other heard saying – whenever a block READs into memory will be in CR mode while if the block is fetching for UPDATE it will be in XCUR mode so that sessions can apply the (more...)

RMAN-06023: no backup or copy of datafile # found to restore

There’s a great note from MOS – Checklist for an RMAN Restore (Doc ID 1554636.1) but how many of you review this before performing a restore?

If you don’t then you are as guilty as I am.

RMAN> restore database until time "TO_DATE('2015-MAR-04 19:53:54','YYYY-MON-DD HH24:MI:SS')" preview summary;

Starting restore at 2015-MAR-05 18:03:28
allocated channel: ORA_DISK_1
channel ORA_DISK_1: SID=9 device type=DISK

datafile 5 will be created automatically during restore operation
datafile 6 will be created  (more...)

Sequences – a quick guide and an unexpected quirk

Sequences on Oracle databases are simple, but there are some basic truths about sequences which need to be understood if you are going to use them, especially on RAC:

 

  1. Sequences will have “holes” in them, even if you specify NOCACHE (e.g. if you rollback your transaction).
  2. Don’t specify NOCACHE. It doesn’t scale.
  3. Sequences will NOT necessarily be, erm, sequential for your transactions. That will depend upon the COMMIT order and if you are (more...)

Remote graphical installs

Most of my servers tend to be Linux VMs on VMware ESX without any graphics desktops setup, so it can be disconcerting trying to install Oralce with it’s graphical “runInstaller” being the gate way we have to cross to achieve installation.  Of course there is the silent install, but to do that requires knowing all the secret handshake responses to make the silent installer work. Often the easiest way to get a response file is to (more...)

HotSOS symposium 2015

This week I participated (online option) in HotSOS conference — the only conference that is focused entirely around Oracle database performance and internals. Like a year ago, it was a great conference, I really enjoyed it. Predictably, the number one topic was the in-memory option. Probably every third talk was about it. I learned a lot of stuff I didn’t know before (and I strongly suspect that this stuff wouldn’t be easy to find anywhere else).

(more...)

Distributed Transactions and EM12c Page Performance

While presenting at HotSos in Dallas, Tx, an attendee, (thank you Wenju! :)) asked how page performance issues could be identified when the call was being made remotely and not from the Oracle Management  Repository, (OMR) using the Page Performance console within Cloud Control.

This is a very good question and although not straight forward, I would like to demonstrate what is available to assist in answering the challenge.

First, I have to add that (more...)

Blog third anniversary

My first blog post was March 5, 2012, three years ago today.

I have enjoyed blogging.  Even though I am talking about topics related to my work blogging does not feel like work. The great thing about blogging is that it’s completely in my control.  I control the content and the time-table. I pay a small amount each year for hosting and for the domain name, but the entertainment value alone is worth (more...)

Adding An EMC XtremIO Volume As An ASM Disk With Oracle Database 12c – It Does Not Get Any Easier Than This.

When Something Is Simple It Must Be Simple To Prove

Provisioning high-performance storage has always been a chore. Care and concern over spindle count, RAID type, RAID attributes, number of controller arms involved and a long list of other complexities have burdened storage administrators. Some of these troubles were mitigated by the advent of Automatic Storage Management–but not entirely.

Wouldn’t it be nice if the complexity of storage provisioning could be boiled down to but (more...)

Joined twitter

I joined twitter.  I don’t really know how to use it.  I’m setup as Bobby Durrett, @bobbydurrettdba if that means anything to you. :)

– Bobby

Oracle University Instructors on the Cruise Ship

Oracle User Group Norway Annual ConferenceI’m really looking forward to speak at the Oracle User Group Norway Spring Seminar 2015, together with my dear colleague Joel Goodman! For sure it’s one of the highlights this year in terms of Oracle Events.

Joel will present about Oracle Automatic Parallel Execution on MAR-12, 6pm and about Oracle 12c Automatic Data Optimization and Heat Map on MAR-13, 9:30am

Yours sincerely will talk about The Data Guard Broker – Why it is recommended on (more...)

Oracle APEX_WEB_SERVICE REST API call

In this post I will try to show you how I used the Oracle Apex and the APEX_WEB_SERVICE  PL/SQL package to quickly send a request to a public Internet API and how I handled the response. The code below was written during a 'Hackday' and hasn't been extensively tested.

My use case is integrating Oracle Apex with the public Mendeley REST API for Mendeley Catalog Search.

The idea was to build an (more...)

OAM 11GR2PS2 in a day

Get Access Manager 11gRel2 PS2 installed in a day Goal is to get OAM installed and configured in a day - with full control; that is without using the Installation Wizard. Virtual Box Start with Virtual Box. Allow plenty of memory (10GB), and disk (120GB). Attach V33411-01.iso (Oracle Server V6.3) to the CD, and boot. Minimal (not Basic server!) install, configure network with static IP

In Memory XML Performance (XVM)

I wouldn’t believe the bad XMLType performance statement given stated in Martin Preiss’ blog post,…

Restoring Slave when GTID is enabled on master

This is a quick post on issues I faced while restoring a slave when GTID was enabled on master.

I have master created few days back and now I am trying to create a slave. I have GTID enabled on master.

Master status:

root [mysql] >show master status G
*************************** 1. row ***************************
             File: bin_log.000002
         Position: 16682
     Binlog_Do_DB:
 Binlog_Ignore_DB:
Executed_Gtid_Set: f7718b80-c237-11e4-baa8-a0369f370a52:1-59
1 row in set (0.00 sec)
root [mysql] >show  (more...)

Database Provisioning in Minutes: Using Enterprise Manager 12c DBaaS Snap Clone and NetApp Storage

Last week, I was letting you know about an opportunity to hear all about the Snap Clone functionality with EMC storage. This week, there’s a similar presentation on Wednesday, March 4 at 8AM PT (San Francisco), 11AM ET (New York), 4PM GMT (London) and 5PM CET (Paris), only this time we’re discussing Snap Clone with NetApp storage instead.

To register, go to this link.

What is an INDEX SKIP SCAN?

I tested this on Oracle 11.2. First I created a table with two columns. The first column, OWNER, had low cardinality i.e. it had only two possible values, PUBLIC and SYS. The second column, OBJECT_NAME, had the names of all objects owned by PUBLIC and/or SYS so it had high cardinality i.e. it had many different values:

SQL> conn system/manager
Connected.
SQL> create table t1 as
  2  select owner, (more...)

RMOUG 2015 Training Days Review

I’m at HotSos Symposium 2015 speaking this week, so thought I would blog about the results of the conference I’m the director of and that finished up just two weeks ago.  I’m not admitting to being overwhelmed by OEM questions here, as I’m rather enjoying it.  I love seeing folks so into Enterprise Manager and look forward to more!  Keep the ideas for more blog posts coming!  I’ll write on all these great topics in (more...)

Creating UKOUG Tech15 – The View from the Inside

At the end of last week I was contacted by the UKOUG who asked me if I would agree to be on the planning committee for the annual technical conference this year – Tech15. Not only that but I was privileged to be asked to repeat my role from Tech14 and be the Lead for the Database area. I am of course happy to do so.

UKOUG_Tech15 Banner
Why do I mention this? Well, this year I (more...)