libstdc++-libc6.2-2.so.3 on Ubuntu

error while loading shared libraries: libstdc++-libc6.2-2.so.3:
cannot open shared object file: No such file or directory

sudo apt-get install libstdc++2.10-glibc2.2

Sometimes it needs to exactly mimic Oracle's ROWNUM where is no possibility to initiate a counter in previous statement by SET @rownum:=0;.
It is still possible in a single SQL.

SELECT @rownum:=@rownum+1 rownum, t.*
FROM (SELECT @rownum:=0) r, mytable t;

check process mongrel_0 with pidfile <SOME-DIR>/shared/log/mongrel.4000.pid
    start program = "mongrel_rake.sh start_0"
    stop program  = "mongrel_rake.sh stop_0"

    if totalmem is greater than 100.0 MB for 5 cycles then restart       # eating up memory?
    if cpu is greater than 50% for 2 cycles then alert                  # s an email to admin
    if cpu is greater than 80% for 3 cycles then restart                # hung process?
    if loadavg(5min) greater than 10 for 8 cycles then restart          # bad, bad, bad
    if 3 restarts within 5 cycles then timeout                         # something is wrong, call the sys-admin

    if failed port 4000 protocol http                   # check for response
        with timeout 10 seconds
        then restart
    group mongrel

set daemon 60
set logfile monit.log
set pidfile monit.pid 
set statefile monit.state

set httpd port 9999
    use address localhost
    allow username:password

Mongrel이 말을 듣지 않으면 Kill -9

Posted by deepblue 22 days ago

mongrel_rails  stop  [options]

mongrel_rails -f -w 5

 def stop(i)
  pid = "#{APP_HOME}/shared/log/mongrel.400#{i}.pid"
  system "mongrel_rails stop -P #{pid} -c #{APP_HOME}/current"

  if File.exists?(pid)
    system "mongrel_rails stop -P #{pid} -c #{APP_HOME}/current -w 5 -f"
    system "rm #{pid}"
  end
end 

Modal Windows

Creating a popup window is reasonably easy if you just want another browser window of a specified size and you don't care if your visitors swap back and forward between the various browser windows. Where it becomes difficult (if not impossible) is where you want the new window to stay in front of the original window and not allow your visitor to interact with the original window until the new window has closed. We call a window that insists on retaining the focus like this a modal window.

The difficulty is that Javascript does not have a standard way of creating a modal popup window the way it has a standard way to create an ordinary (modeless) window by using window.open().

A number of browsers (for example Netscape 4 or any version of Opera up to and including version 9) do not allow you to make a popup window modal at all. There is simply no command that you can use that will make a window modal in those browsers.

There are two groups of browsers that do allow you to create modal windows and each uses a different method to do so.

Internet Explorer adds an entirely new method to the window object to open a modal window - window.showModalDialog(). If you use that to try to open a modal window then if your visitor is running Internet Explorer then a modal window will be opened. If they are running some other browser then all they will get is a Javascript error.

The Mozilla based browsers (Netscape 6+, Firefox, etc) use a completely different method to declare that the window that is opened should stay in front . They use the normal window.open and just add an extra attribute modal=yes to the list of atributes that define the appearance of the window (unfortunately it still doesn't actually make it modal it just forces it to stay in front which is the best that you can do with these browsers). If you try to use this to try to open a modal window then the window will open in any browser (provided that it hasn't been blocked by a popup blocker) but it will only stay in front if the browser is one of the Mozilla based family. If your visitor is running Netscape 4, any version of Opera, or Internet Explorer etc. then the window will still open it just wont stay in front.

The best that we can do to set up a window that is as modal as we can make it is to combine these two together to create code that will open a modal window in Internet Explorer, keep the window in front in Mozilla based browsers, and which will just open a non-modal window in those browsers that don't support modal windows. Of course we don't want to test which browser that the browser itself claims to be since most Opera browsers are set to report that they are Internet Explorer. Instead we test for support for the showModalDialog method itself to identify those versions of Internet Explorer that support it. Combining the code together gives us the following (with the amendments from an ordinary non-modal window shown in bold).

function modalWin() {
if (window.showModalDialog) {
window.showModalDialog("xpopupex.htm","name",
"dialogWidth:255px;dialogHeight:250px");
} else {
window.open('xpopupex.htm','name',
'height=255,width=250,toolbar=no,directories=no,status=no,
menubar=no,scrollbars=no,resizable=no ,modal=yes');
}
}

All that remains is to set up the code to call our modal window function (and of course to allow those without Javascript to have the window open in a separate non-modal browser window as well.

If you want to see what effect that using all of the above code has in your particular browser then click here and if your browser supports modal windows then that is what will open and you will have to select the close link to close that window before being able to return to this page. If your browser doesn't support modal windows then the window will still open but it will not be modal.

MySQL: Get total number of rows when using LIMIT August 11, 2006

Every now and then you need to limit the number of rows MySQL returns, i.e. use the LIMIT clause. Result set pagination is by far the most often usage of LIMIT clause, since you usually want to select only rows you’ll be displaying on certain page.

The problem is that for pagination you also need total number of rows in a result set, so you know how many pages you’ll have. This usually means that you need to execute query two times. First query is for counting total number of rows without LIMIT. Second query is exactly the same as the first, just without LIMIT and it will actually retrieve required data. You would need two queries like these:

SELECT COUNT(*) FROM users WHERE name LIKE 'a%';

SELECT name, email FROM users WHERE name LIKE 'a%' LIMIT 10;

Now, this is not such a big problem when you have small result sets and/or simple queries. But if you have a complex query that joins several tables and takes a while to execute - well, you probably wouldn’t want to execute it twice and waste server resources.

Luckily since MySQL 4.0.0 you can use SQL_CALC_FOUND_ROWS option in your query which will tell MySQL to count total number of rows disregarding LIMIT clause. You still need to execute a second query in order to retrieve row count, but it’s a simple query and not as complex as your query which retrieved the data.

Usage is pretty simple. In you main query you need to add SQL_CALC_FOUND_ROWS option just after SELECT and in second query you need to use FOUND_ROWS() function to get total number of rows. Queries would look like this:

SELECT SQL_CALC_FOUND_ROWS name, email FROM users WHERE name LIKE 'a%' LIMIT 10;

SELECT FOUND_ROWS();

The only limitation is that you must call second query immediately after the first one because SQL_CALC_FOUND_ROWS does not save number of rows anywhere.

Although this solution also requires two queries it’s much more faster, as you execute the main query only once.

You can read more about SQL_CALC_FOUND_ROWS and FOUND_ROWS() in MySQL docs.

퍼온 글...

주제는 my.cnf파일을 수정한 후에 create database를 euckr로 생성해야함.

====================================================

/etc/mysql/my.cnf 파일에서..

[client]
...
default-character-set = euckr

[mysqld]
...
default-character-set=euckr
init_connect = SET collation_connection = euckr_korean_ci
init_connect = SET NAMES euckr
charater-set-server = euckr
collation-server = euckr_korean_ci

[mysqldump]
...
default-character-set=euckr

[mysql]
default-character-set=euckr

수정후에 mysql을 다시 띄움

==============================================

mysql이 4.1로 업그레이드 되면서 서브쿼리가 지원되게 되어

아마도 많은 사람들이 개발시점에서 한 번쯤은 mysql4.1을 사용할지

고민했으리라 생각합니다.

그러나 아직 제대로된 버전이 아닌관계로 버젓한 메뉴얼이 없어

변화된 localization셋팅때문에 많은 분들이 고생했을 것이라 예상합니다.

mysql4.1에서는 4.0에서처럼 default character set하나만 바꿔주면 끝나질

않습니다. 서버/데이터베이스/테이블/connection/ 심지어 필드

하나하나, 스트링 하나하나까지도 character set과 collation을 설정할 수

있게 되었습니다. 그래서 4.0에서 서비스하던 사이트를 4.1로

데이터를 옮기는 과정에서 한글이 깨지는 현상이 발생합니다.

쉽게 말씀드리면 4단계에 걸쳐서 각각 character set과 collation을

변경해주시면 됩니다. 우선 데이터베이스를 다음과 같이 새로 생성합니다.

>> create database DB_NAME character set euckr collation euckr_korean_ci

그리고 4.0의 데이터를 스크립트로 복사한 다음 각각의 테이블 끝에

붙어있는 character set을 euc-kr 이나 latin1에서 euckr로 변경해줍니다.

(4.1에서 한글의 character set이름이 euc-kr에서 euckr로 변경되었습니다.)

그런 다음 mysql 을 --default-character-set=euckr --default-collation=euckr_korean_ci 의 옵션을 주어 실행시키면서 자료를 덤프받습니다.

>> mysql -uroot -p --default-character-set=euckr --default-collation=euckr_korean_ci < DB_SCRIPT.SQL 

(DB_SCRIPT.SQL파일은 4.0에서 받은 데이터 스크립트파일이겠죠.)

그렇게 하면 일단 데이터베이스 어필리케이션(예를 들면 SQLyog같은 프로그램)에서는 정상적으로 데이터를 볼 수 있을 것입니다.

하지만 JDBC를 사용해서 접속하는 경우 connection characterset을  따로

설정해주지 않으면 한글이 깨질 것입니다.

저같은 경우 어플리케이션에서 connection을 얻어오는 즉시

해당 connection을 이용하여 "SET CHARACTER SET euckr"이란

SQL명령을 executeUpdate 시켰서 해결했습니다만 아마도 더 깔끔한

방법이 있을 줄 압니다.

그렇게 하면 mysql4.1.1알파에서도 한글을 문제없이 사용할 수 있습니다.

참고로 그냥 latin1으로 설정한 상태에서도 한글이 사용이 가능하긴 합니다만 order by나 일부 한글로의 검색시에 제대로 검색이 안되는 경우가 발생합니다. 그런 경우 해당 필드만 character set을 설정해서 사용할 수도 있습니다. 예를 들면 latin1으로 저장된 한글을 euckr의 코드셋 순서로 정렬하고 싶을 때 다음과 같이 하면 됩니다.

>> SELECT * FROM table_name ORDER BY k COLLATE euckr_korean_ci

그러면 한글 순서로 정렬이 됩니다.

이 말은 만약 이제까지 latin1으로 잘 써오신 분이라면 정렬을 위해서만 추가적으로 코드를 추가해줄 경우 문제없이 잘 정렬이 됨을 의미하는 것이니 데이터베이스를 통째로 수정할 필요가 없겠지요.

저도 초보라 고생끝에 알아낸 팁입니다. 유용하게 참고하셨으면 좋겠습니다.