Monday, December 12, 2005

virtual indexes

Jonathan has a very good post on the oracle-l list on virtual indexes. alsthough i've known about this for wa while never had a chance to play around with them.
this post is a goos expalnation with use pro and cons .
-----------------------------------
In the context of "Tales of the Oak Table", the virtual indexes were, indeed, access paths intothe x$ fixed tables. They can be seen in thevirtual table v$indexed_fixed_columns, whichhas the structure:
Name Null? Type
----------------------- -------- ------------
TABLE_NAME VARCHAR2(30)
INDEX_NUMBER NUMBER
COLUMN_NAME VARCHAR2(30)
COLUMN_POSITION NUMBER
These exist and are predefined.
The Virtual Index Wizard probably relates to the"nosegment" feature, whereby you can do the following:
create index t1_noseg on t1(small_vc) nosegment; alter session set "_use_nosegment_indexes"=true;
From this point on, your session can use EXPLAIN PLANto see if the optimizer would use this index if it existed, butyou don't have to build it, and no-one else can see it. On the plus side, it gives you some idea about whether a newindex is worth building; on the minus - the statistics are inferredfrom the column statistics, so there is no guarantee that the indexwould be used if you really created it.
Regards
Jonathan Lewis

Monday, November 21, 2005

Table Compression - Order For Maximum Compression - Code Utility

i've been alittle lazy with blogging but i was reading this article /blog and found it interesting to post


http://oramossoracle.blogspot.com/2005/11/table-compression-order-for-maximum.html

Wednesday, September 14, 2005

AskTom "Undocumented secrets for super-sizing yo..."

ANother post in the ever growing saga of the good the bad and dare i say the ugly.



AskTom "Undocumented secrets for super-sizing yo...": "fix it, then you look for help. If you can't afford help, then you get what you
pay for.

Do everybody a favor and stop trolling. It does no good here.
"

Google Blog Search

Google has entered in the Blog search Arena too. This service is not only aimed at blog searches from the blogger website which google owns but aims to search across every blog that has a feed out there.
What next Google?

Friday, September 02, 2005

Oracle WTF

i found this this morning while i was reading ora blogs and it does remind me of some of my most common mistakes.
if nothing atleast someone wont make them by reading this blog. Enjoy

Oracle WTF

Tuesday, August 23, 2005

Monday, July 11, 2005

Communication Problems (JL Comp)

Again another interesting article by J.Lewis.
I had the opportunity not only to attend ioug but also attend this presentation.
It was rather interesting as to What don burleson perceived since myself being one of the audience did not look at it that way. infact this session was one of the sessions where i actually learnt and understood a lot of concepts that i didn't know about

Communication Problems (aka the response )

10g release 2 for linux

well 10 release 2 for linux is out now (well since jul 6th).
technet (http://technet.oracle.com) is carrying a tiop 20 cool features stuff and tom kyte has very cool article on his blog http://tkyte.blogspot.com
about dml errors . the concept seems not only interesting but something very well worth testing and maybe using in data warehousing and maybe oltp systems.
looking thru the licensing schema i was dissapointed the transparent encryption and encryption for rman backups was a seperately licensed product.
this kinda sucks since oracle is desperately tryingto make more revenue wheras companies are trying to shrink it budgets.
but ooh well maybe in some release oracle will bundle the features up may 12 ????

Monday, June 20, 2005

10gr2 release soon

seems like oracle is throwing out another release to the masses.
10g release 2 is supposed to be out and available by end of this month.
though this release doesnt promise much in way of enhancements . lets hope it does in terms of bug fixes.

InformationWeek > Oracle 10g Release 2 > Oracle Shoots For Database Lead > June 20, 2005

Monday, May 16, 2005

The Tom Kyte Blog: On Blogging

Abit away from oracle . Tom kyte has a very interesting post on blogging and some interestign blogs are listed .
The Tom Kyte Blog: On Blogging

ioug 2005

Finally I get a chance to write about ioug 2005 .
The event was full of sessions , I attended Jonathan Lewis
understanding and assisting the oracle optimizer which was a very good seminar.
The rest of the days there were a lot of sessions that were of interest.
though I wasn't very satisfied .
a lot of the content was the same stuff that is already available to the general masses . There were only a couple of interesting papers .
Unlike hotsos which I've grown to like this was not a focused event.
There were too many sessions and you obviously cant go to all of them.
The tom kyte live was a fun event as well as tom's presentation on bulk binding .
Binding has always been a issue for me since its should I go all binds or not.
developers level static SQL for some reason but the oracle engine doesn't.
With prepared statement every thing is potentially a bind but as tom pointed it that in it self is also a problem.
contains presentation of should you rebuild indexes was very interesting .
he proved the fact that function based indexes can be used by a rule based optimizer since they are not technically a function rather a virtual column.
Cary's presentation was added in last minute but the topic of discussion was very interesting and something we face on a regular basis.
All these developers want to build all these applications but no one wants to build a debugging mechanism until they actually have a problem.
Cary presented a lot of stuff saying how he would like a trace file to actually be ,
There were a couple of non oracle session like how to manage meeting and stuff.
There were aloto f vendor based presentation discussing how their products can change the world.
and it seemed that everyone has embraced the wait based methodology. confio and a whole slew of companies are bringing out products that monitor and tune using wait based.
CA had a big presence as well as the folks from TUSC.
There are a loto f good presentation available on the ioug.org website.

Tuesday, April 05, 2005

Debating Skills (JL Comp)

Going over mark rittman's blog i found aother article by jonathan lewis titled can we have a sensible debate.
The debates outlines a couple of thing that are interesting point ot note is the topis iof the thread that jonathan mentions
empirical vs research DBA .
The point in fact that is real world knowledge better or research is the key to sucess.
Hey if someone hadnt proved it to me that i've been wrong i would have still be wrong wouldnt I.
Enjoy
Debating Skills (JL Comp)

� Updateable External Tables

While looking at orasblogsi found this very interesting article about updateable external tables. although i prefer the use of external tables as a good read only medium for my flat file the concept is pretty interesting and could have good implications on some applications.
� Updateable External Tables

10g R2

Bert Scalzo has an interestign post baout 10g r2 and the connect role.
Date: Sat, 2 Apr 2005 19:17:18 -0800
From: "Bert Scalzo"
Subject: FYI - 10g Release 2
Oracle 10g Release 2 is in its third and final beta - and should release
this summer ...
Found my first interesting Oracle 10g Release 2 issue that will effect
lots of people ...
When Oracle 7.0 came out, they created three pre-canned roles (DBA,
RESOURCE, and CONNECT) that were really just short hand notations to
ease people migrating from Oracle 6.0 - but the general recommendation
has always been "NOT" to use these, but rather create your own roles.
Well in Oracle 10g Release 2 they've changed one of these pre-canned
roles - CONNECT. I hate to admit it - but this broke a some of my
scripts. I imagine many other Oracle users will have issues as well.
10g Release 1 and prior - CONNECT had:
GRANT CREATE DATABASE LINK TO CONNECT;
GRANT CREATE SEQUENCE TO CONNECT;
GRANT CREATE SYNONYM TO CONNECT;
GRANT CREATE SESSION TO CONNECT;
GRANT CREATE CLUSTER TO CONNECT;
GRANT ALTER SESSION TO CONNECT;
GRANT CREATE TABLE TO CONNECT;
GRANT CREATE VIEW TO CONNECT;
10g Release 2 beta - CONNECT now only has:
GRANT CREATE SESSION TO CONNECT;
Bert

Monday, March 14, 2005

Oracle HTML DB 2-Day Developer

Thanks for sergio for pointing to this link in his blog.
This is a collection of howto's and infodocs on using Htmldb.
htmldb is a easy RAD tool for creating and deploying intranet and internet sites with all sorts of features built in.
Oracle HTML DB 2-Day Developer

Thursday, March 10, 2005

Tuesday, March 08, 2005

Hotsos Symposium, Day 1

This is Jonathan Gennick's Blog on Day 1 of Hotsos symposium.
Though i wasnt able to go there this year. i can easily vouch for this being the conference with the best technical minds in the industry gathering.
Hotsos Symposium, Day 1

Tuesday, March 01, 2005

Peter Bach On Statistics Collection Strategies

Mark rittman's blog has anice article on Statistics collection when and how .
This article also referes to Jonatha Lewis Article Gathering Statistics How often and how precise.
This is actually a very important consideration since a 24x7 system
has a lot od constraints associated with it. and CBO behaviorla change doesnt tend to help in some situations.
Peter Bach On Statistics Collection Strategies

Tuesday, February 08, 2005

optimizing the Oracle Optimizer

Since Oracle Optimizer is a black box in terms of the decisions it makes (extended tracing is the only way to see that).
There are some parameters that always require tweaking t actually get the job done .
\Beware getting the job done doesnt mean the job is always done right.
: "compare "

Jonathan Lewis on 10g

Jonathan has a good article to justify the upgrade to 10g and look behind the hype of the new database.
DBAzine.com: the online portal for database issues and solutions

Thursday, January 27, 2005

metalink Plugin courtesy of Oracle-l and Matt penny

This is a cool Plugin for all you Firefoz users.


– Check-out this great Oracle-l extension, courtesy of Matt Penny:

http://www.freelists.org/archives/oracle-l/12-2004/msg00459.html

Copy the two items into your

C:\Program Files\Mozilla Firefox\searchplugins directory:

metalink.gif

http://www.cbdba.net/images/metalink.gif



Wednesday, January 19, 2005

Security Advisory

Pete Finnigian has put together an alert about using directory objects.
this has been fized in Oracle latesh Security Advisory Date 01-18

Friday, January 14, 2005

Database Links

For all those who use database links arnd are worried about Database links what they are how they are sued and what are the ramifications. here is a good Article .

Database Links

Sox Deal with it.

As pete States the SOX stuff is heatign up as Yearly Audits come into play.
SOX is a very Broad Law and in that sense has little or no explanantion on what the auditors want thus leaving it up to the auditors to determine what's right and wrong.

Pete Finnigan's Oracle security weblog

Bind variables - The key to application performance

Everyone Talk on and on about why bind variables are good .
Yet Application Developers still think it is easier to code using literals or string concatenation.
This interesting article again stresses the point as to where we should use bind variables and Why.


Bind variables - The key to application performance

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