Archive for April, 2009

Playing With Free Yum….

Posted by Aman Sharma in genernal on April 16, 2009

I use Oracle Enterprise Linux at my home. Now there are lots of talks that one should use Centos as it does give away free patch updates even or one should actually go and buy Red Hat’s Enterprise Linux as its proven one but I guess, both the logics don’t serve very well for me. I don’t run a data center at my home so I really am not bothered about patches and all that stuff , whether they are free or paid. I have seen RedHat being used almost all the places so some thing which is just a clone of it and is coming without any cost, I guess, I should use that. I have not seen Centos being used so far anywhere, at least where ever I have visited. So for a guy with almost no cash, OEL is a perfect solution ;-) .

Since OEL is free of cost, oracle won’t give the critical patch updates of it freely. But they have decided to give away the RPMs of it free of cost which are other wise also available on the installation media.  Sergio posted a note about the release of the free YUM server here,

http://blogs.oracle.com/sergio/2009/03/new_oracle_public_yum_server_1.html

So I just thought , let’s give it a try. So I just checked the instructions mentioned at the Public YUM’s site, http://public-yum.oracle.com/

First we have to rename the Oracle_base file which is available at /etc/yum.repos.d. Under this , originally I had, ULN-Base.repo file which I renamed as ULN-Base.repo.disabled. Second step is to get the required file for my version through WGET, so I used,

This got the required file over my box. Next step was to locate the right section from whre I want to get the updates. So for my OEL 4 version with 6 update, I did this,

more public-yum-el4.repo
[el4_u6_base]
name=Enterprise Linux $releasever U6 – $basearch – base
baseurl=http://public-yum.oracle.com/repo/EnterpriseLinux/EL4/6/base/$basearch/
gpgkey=http://public-yum.oracle.com/RPM-GPG-KEY-oracle-el4
gpgcheck=1
enabled=1        <<—- Changed from 0 to 1

[el4_u7_base]
name=Enterprise Linux $releasever U7 – $basearch – base
baseurl=http://public-yum.oracle.com/repo/EnterpriseLinux/EL4/7/base/$basearch/
gpgkey=http://public-yum.oracle.com/RPM-GPG-KEY-oracle-el4
gpgcheck=1
enabled=0

Well, that’s all! After this, time was to test this Yum thing. So as given in the faq site , I thought to update my Firefox. Here is a long list of things which happened when I entered,

[root@oracle yum.repos.d]# yum install firefox
Setting up Install Process
Setting up repositories
Reading repository metadata in from local files
Parsing package install arguments
Resolving Dependencies
–> Populating transaction set with selected packages. Please wait.
—> Downloading header for firefox to pack into transaction set.
firefox-1.5.0.12-0.3.el4. 100% |=========================|  83 kB    00:01
—> Package firefox.i386 0:1.5.0.12-0.3.el4.0.1 set to be updated
–> Running transaction check

Dependencies Resolved

=============================================================================
Package                 Arch       Version          Repository        Size
=============================================================================
Updating:
firefox                 i386       1.5.0.12-0.3.el4.0.1  el4_u6_base        15 M

Transaction Summary
=============================================================================
Install      0 Package(s)
Update       1 Package(s)
Remove       0 Package(s)
Total download size: 15 M
Is this ok [y/N]: y
Downloading Packages:
(1/1): firefox-1.5.0.12-0 100% |=========================|  15 MB    06:14
warning: rpmts_HdrFromFdno: V3 DSA signature: NOKEY, key ID b38a8516
Public key for firefox-1.5.0.12-0.3.el4.0.1.i386.rpm is not installed
Retrieving GPG key from http://public-yum.oracle.com/RPM-GPG-KEY-oracle-el4
Importing GPG key 0xB38A8516 “Oracle OSS group (Open Source Software group) <bui ld@oss.oracle.com>”
Is this ok [y/N]: y
Key imported successfully
Running Transaction Test
Finished Transaction Test
Transaction Test Succeeded
Running Transaction
Updating  : firefox                      ######################### [1/2]
Cleanup   : firefox                      ######################### [2/2]

Updated: firefox.i386 0:1.5.0.12-0.3.el4.0.1
Complete!

Alright, so it seems that this YUM did work, cool! At least now I won’t be required to run to the DVD of OEL 4 that I have when ever I need some RPM to be installed. How about buying support? Well, I guess, in 119$ , that’s not much costly ;-) .

,

4 Comments

Virtual Index, A New Learning….

Posted by Aman Sharma in genernal on April 10, 2009

I always say that no one is perfect when it comes to a tech discussion. There is always a very fare chance that you may not be knowing something and/or have not seen/heard about it before. Almost everyday , you can learn some thing new. The same happened with me too today. While discussing about Indexes,what they are,how they work, one delegate pointed out that there  is a concept of “Virtual Indexes” in oracle from 9i onwards. As the name suggests, these indexes basically are used to test  that whether the existance of an index can be good/bad/of no effective or a column. Though these are actually created by a create command, they do not store  any data as such and just contain statistics. So if we get a recommendation from Sql Access Advisor tool of 10g, that we should be having an index on a column of our table, we can use these indexes to test that whether this index will work  for us or not? ? Sounds cool, right! Yes, its indeed is but  the only sad part was , I didn’t know about this before :-( . So when was told, I started to look for the information about these indexes and I found this,

http://www.dbazine.com/blogs/blog-cf/chrisfoot/blogentry.2007-05-31.6959101573

An excellent note by Chris Foot, explaining in gory detail about the indexes. This post had a demo page too linked with it, so I am not going to repeat the same demos again here. You may want to look at the demo page,which is mentioned in the post itself. I shall just mention one thing, which is for my reference, you can create virtual indexes by  adding a keyword, ” NOSEGMENT” to the Create Index command like this,

sql> create index tidx on test(empno) nosegment;

In order to use these indexes, you need to set an undocumented parameter, “_use_nosegment_indexes”=true like this,

sql> alter session set set “_use_nosegment_indexes”=true;

Surely enough,it was a new and informative learning at least for me as I didn’t know about these virtual indexes before. Please refer to the above mentioned blog post to read more about them. Once again, learned something new, great!

7 Comments