Blog Aggregator - Amardeep Sidhu

Few days ago i posted about DBAzine being down. I was just checking to see if its back.
Its rocking now.
Welcome back DBAzine.com

Quite some time back I made a blog entry about deploying Oracle Clusterware for non-RAC purposes. As I pointed out in that entry, there were license ramifications. That was then, this is now.
In this press release about Oracle Clusterware, Oracle is announcing that Oracle Enterprise Linux (with Unbreakable Linux Support) can deploy Oracle Clusterware to […]

I’ll be in Estonia on the 3rd & 4th of June doing a PL/SQL seminar. I’m guessing the details will be available here in the next day or two.
Cheers
Tim…
PS. If I get any more dates I’m printing a “World Tour” T shirt.

After the interesting comment storm on Doug’s blog when he posted some of Tim Gorman’s comments on the value of data in his career experiences as compared to the value of the applications manipulating that data, I hesitate a little to post this.
But, I can’t stop myself because it’s such an interesting insight!
Anand Rajaraman, ex-Director […]

Here is a table with a single row of data.

SQL> create table my_tab (c2 char(2))  2  /

SQL>  insert into my_tab (c2) values (’Y ‘)  2  /

1 row created.

SQL>

Which of the following queries will match that row?

select * from my_tab where c2 = ‘Y’/

select * from my_tab where c2 = ‘Y ‘/

select * from my_tab where c2 = ‘Y  ‘/

If you said all three you get a cigar (providing you live in a jurisdiction where such infernal devices are still permitted).

SQL> select * from my_tab where c2 = ‘Y’;c2–Y

SQL> select * from my_tab where c2 = ‘Y ‘;c2–Y

SQL> select * from my_tab where c2 = ‘Y  ‘;c2–Y

The reason is due to Oracle’s rules for comparing blank-padded datatypes. If the two values are of differing sizes Oracle pads the smaller variable with the requisite number of blank spaces. Obviously it is documented.

On the whole I think this is a boon - CHAR columns are a pain in the neck at the best of times, without having to worry unnecessarily about additional RPAD calls. This is unfortunate if you are relying on ‘Y ‘ being different to ‘Y’; but if your application depends on trailing spaces for data integrity then you probably have bigger problems.

Thought it might be worth looking at the impact on the performance of Unique and small index range scans as typical in OLTP environments, when an index is rebuilt in a larger block tablespace.
Warning, this discussion will again primarily be an exercise in simple mathematics. However, a few little details to start the ball rolling.
I’ve already discussed how in many scenarios, […]

Whilst Oracle BI Answers is a pretty good ad-hoc query tool, it’s not really an OLAP tool and Oracle’s current recommendation if you want that sort of thing is to use Hyperion Web Analysis, which comes bundled with the latest version of OBIEE, OBIEE “Plus”. Hyperion Web Analysis connects to Essbase, Microsoft Analysis Services and […]

I’m writing this post sitting on the express train going from Oslo Airport to the centre of Oslo, traveling over to Norway for the Norwegian User Group conference this week. I’ve been invited over as a guest of the user group to do a couple of presentations on Oracle BI, it’s been a bit of […]