Pythian Group Blog » Blog Archive » Pythian Goodies: The Answer to Free Memory, Swap, Oracle, and Everything

Pythian Group Blog » Blog Archive » Pythian Goodies: The Answer to Free Memory, Swap, Oracle, and Everything:

"# Linux Oracle servers must use HugePages.
# Being low on free memory is not an issue.
# Using DirectIO is important to maintaining a useful file system cache."

"If the system is capable of running 64-bit Linux then it should. Using the VLM workaround adds significant overhead to database cache access."

real world sql tuning tips

1. only CBO. RBO is dead.
2. 90-9-1 stats methodology. Don't touch optimizer parameters, refine your stats!
3. check the cardinality, compare the optimizer estimated and the actual one.

SQL> alter session set statistics_level=all;
SQL>
SQL> select * from table(dbms_xplan.display_cursor(null,null,'allstats last'));you can also find actual plan with stats from v$sql_plan_statistics_all

4. notice when stats are not enough and optimizer exceptions

A tip for changing JDK used by JDeveloper

Web Services on Drugs: Changing the version of JDK used by JDeveloper
In short, move (rename) the embedded JDK to another place. Then restart JDev.

How to find out JDBC statement leaks in Oracle

Serious leaks can be identified with then following SQL (10g):
select oc.inst_id, oc.sid, oc.hash_value, oc.sql_text, count(*)
from gv$open_cursor oc
where sql_text not like 'COMMIT%'
group by inst_id, sid, hash_value, sql_text
having count(*) > 5
order by 5;

9i or belower use v$open_cursor instead of gv$open_cursor

Java packages management system

Linux has RPM/APT, Mac has Fink, Ruby has RubyGems, why Java hasn't a good packages management system yet? Experienced Java developers know the "Jar-Hell". They know the difficulties to management the dependencies of various jar files. They know the problems when J2EE applications use different versions of common libraries...
Will this Jar-Hell be solved by JSR 277: Java Module System or anything else?

Text of Steve Jobs' Commencement address (2005)

Text of Steve Jobs' Commencement address (2005)
Steve Jobs says:
...
You can't connect the dots looking forward; you can only connect them looking backwards. So you have to trust that the dots will somehow connect in your future. You have to trust in something — your gut, destiny, life, karma, whatever. This approach has never let me down, and it has made all the difference in my life.
...
Sometimes life hits you in the head with a brick. Don't lose faith. I'm convinced that the only thing that kept me going was that I loved what I did. You've got to find what you love. And that is as true for your work as it is for your lovers. Your work is going to fill a large part of your life, and the only way to be truly satisfied is to do what you believe is great work. And the only way to do great work is to love what you do. If you haven't found it yet, keep looking. Don't settle. As with all matters of the heart, you'll know when you find it. And, like any great relationship, it just gets better and better as the years roll on. So keep looking until you find it. Don't settle.
...
And most important, have the courage to follow your heart and intuition. They somehow already know what you truly want to become.

7 Habits For Effective Text Editing 2.0 - Google Video

Basic rules:
find inefficiency; find a quicker way; make it a habit


Habit 1: Moving around quickly
/ to search
use * again and again. * - search for next
use folding

Habit 2: Don't type it twice
Ctrl-N - keyword completion
Omni-completion in Vim 7

Habit 3: Fix it when it's wrong
spellchecker in Vim 7
add new abbrevation - :iabbrev teh the
add keyword for spellcheck - : syntax keyword WordError teh

Habit 4: A file seldom comes alone
ways to find your old files.
:!ctags -R . generate tags for all files under current directory (and sub directory)
:tag init
:tnext
:grep "\\>" **/*.h
:cnext

Go to the file
gf

Habit 5: Let's work together
copy text from vi to Word or other editors.

Habit 6: Text is structured
how to go from warnings/errors to source
map
:cfile %

Habit 7: Sharpen the saw
keep on tuning the set of commands you use
folding
automatic indenting
Plugins
edit files over a network
advanced scripting

2007 Annual Dinner

2007 Annual Dinner

It's a wonderful evening. People present a tons of funny staff, make everyone laugh all the time. Laddies' dance, Shui Hu video, YMCA, OOTV, Xiang Sheng brought by Frank & Minmin, song name guessing and Pascal's 'singing'... There are so many wonderful things, I couldn't count them all. I also showed my voice - not singing, but narrating in our team's stage play, In the Mood for Love. Fortunately I didn't ruin this, as the show was interrupted by applause dozens times :)

Someone said, Life is full, full of surprises. So, to be surprised, I took a 'first-class' seat this evening - right beside Pascal! Yeah, it's a real exciting & funny experience for me :) And, I picked a '018' number and wan a first-lass prize at Lucky Draw, an iPod shuffle! I am a lucky man :) I believe it's a sign of good fortune in 2007, year of pig. Wish everyone in OARDC have a fruitful piggy year too!

An awesome demo movie about integrating Forms & JSF!

An awesome demo movie about integrating Forms & JSF!
It is created by Wilfred van der Deijl, from oraTransplant. He is also going to present his work in ODTUG 2007. Looking forward his great paper:)
www.oraTransplant.nl, it's a good site with many useful material of oracle develop tools. Why I didn't find it ealier?