Hipersonik.com solutions

Oracle chooses full table scan over index while cost is equal

Issue:

Oracle 10/11 chooses in the cost based optimizer for a full table scan instead of using the index. This is done when the cost of both options are equal according to Oracle.

Solution:

There are 2 possible solutions:
1. Use a hint: It garantees that the index will be used all the time;
2. Oracle chooses alphabetically when the cost is equal: Rename your index to a place earlier in the alphabet than your table: This lets Oracle keep its behaviour but still get the index when the cost is equal.

Dataguard fails with divide by zero exception

Issue:

Oracle 10.2.0.3 dataguard fails with a divide by zero exception crashing the memory recovery proces (MRP0).

Solution:

The solution is twofold:
1. Upgrade oracle to 10.2.0.4 (see metalink for details)
2. Just restart the process:
Login with sqlplus.
The database is still running, so just type:
RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;

Recovery should continu (archive logs will be applied).

make fails with stubs32.h not found on 64bit suse 10.3

Issue:

While running make to compile a program, it fails with stubs32.h not found.

Solution:

Create a symbolic link from stubs-64.h to stubs-32.h and run make again. The problem should be solved.

Layout for view is not found

Issue:

You are trying to load a template using the Joomla 1.5 MVC model, but you run into an error 500 - Layout "templatename" not found.

Solution:

Check for typos in the view name and template name. Use lowercase only.
Do not use the word "view" to start your view with. Joomla strips the word view of the template path only (I regard this as a bug, not a feature). It tolerates the word view when resolving the view.html.php file. So for example viewCustomer is not possible. This will resolve to customer for the template name. Try lookatcustomer instead (all lowercase).

Starting JRockit Mission Control

Issue:

Bea JRockit Mission Control does not want to connect to the Bea instance. It reports connection refused.

Solution:

A possible cause is that the -Xmanagement parameter is not in the correct location in the startup string. The startup string should look like:
${JAVA_HOME}/bin/java ${JAVA_VM} ${MEM_ARGS} ${JAVA_OPTIONS} -Dweblogic.Name=${SERVER_NAME} -Djava.security.policy=${WL_HOME}/server/lib/weblogic.policy ${PROXY_SETTINGS} -Xmanagement ${SERVER_CLASS} >"${WLS_REDIRECT_LOG}" 2>&1
With the -Xmanagement parameter just before the starting class.

Howto create a custom button

Issue:

How to create a custom admin interface button in Joomla (1.5).

Solution:

The code to create the button should be as follows:
JToolBarHelper::custom("task","image1.png","image1Over.png","text for underneath the button",Check for list item (true/false),hide main menu after click (true/false));

Call to JTable object results in blank screen

Issue:

In Joomla 1.5 you try to create a new JTable object, but somehow it results in a blank screen. The apache log shows:
Call to a member function bind() on a non-object

Solution:

If it is a new JTable object from a self build component, the name and location of the object need to be in lowercase and as follows:
Location:
Use JTable::addIncludePath(JPATH_ADMINISTRATOR.DS.'components'.DS.'com_yourcomponent'.DS.'yourtablesubdirectory');
to add the path of your JTable objects to the search path of Joomla.
Use lowercase directory names and file names only.
Name the JTable class file name to the object you are trying to load:
$table = & JTable::getInstance('nameofobject','Table');.
The nameofobject has to become your file name: nameofobject.php in the locate indicated in the addIncludePath.

Adding a view results in error 500

Issue:

After adding a view to a component in Joonla 1.5 you get an error 500, view not found, on linux when trying to access this view.

Solution:

Use the view name in lowercase, and also the directory name of the view in lowercase. This (combined with typing the correct view name) should result in a different response (maybe good, maybe a different error 500).

Bea gives error that weblogicWLStore is owned by other thread

Issue:

While using a JMS configuration with multiple persistent stores in Bea WLS 9.2, there is an error stating the following:

<[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default (self-tuning)'> <> <> <> <>
<[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default (self-tuning)'> <> <> <> <>
<[ACTIVE] ExecuteThread: '0' for queue: 'weblogic.kernel.Default (self-tuning)'> <> <> <> <1212496576272> weblogic.store.io.jdbc.JDBCStoreException: [Store:280064]280077 (server="managed_01" store="PersistentStore-01" table="weblogicWLStore")
at weblogic.store.io.jdbc.JDBCStoreIO.checkTableOwnership(JDBCStoreIO.java:1991)
at weblogic.store.io.jdbc.JDBCStoreIO.getTableOwnershipLogical(JDBCStoreIO.java:2104)
at weblogic.store.io.jdbc.JDBCStoreIO.open(JDBCStoreIO.java:382)
at weblogic.store.internal.PersistentStoreImpl.open(PersistentStoreImpl.java:353)
at weblogic.store.admin.AdminHandler.activate(AdminHandler.java:135)
at weblogic.store.admin.JDBCAdminHandler.activate(JDBCAdminHandler.java:64)
at weblogic.management.utils.GenericManagedService.activateDeployment(GenericManagedService.java:237)

Solution:

The persistent store prefix (use the admin interface, edit persistent store) can be altered to have a table per persistent store. This way no table lock conflicts rise and all managed servers can start.

Bea Weblogic 9.2 does not start after upgrade

Issue:

After an upgrade of the Bea Weblogic server, the environment does not want to start. The error from Bea is BEA-149610.

Solution:

Remove from servers your admin server and managed servers. They have something cached, which requires a rebuild from Bea, which fails because it is trying to start the admin server at the same time. After removal of the servers, the environment starts.

Weblogic jar installer in console mode reports to little disk space

Issue:

During the installation of Bea weblogic 10, the console mode installer reports to little disk space available:

Choose Product Installation Directories:
----------------------------------------

BEA Home Directory: [/opt/weblogic]

Product Installation Directories:

"Default Product Home" = [Enter new value or use default "/opt/weblogic/wlserver_10.0"]

** Insufficient disk space! The installer requires:
** 91MB for the BEA Home at /opt/weblogic,
** 362MB for the product at /opt/weblogic/wlserver_10.0 and
** 367MB temporary work space at /tmp/bea50538.tmp.
** There is only 375MB available at /tmp.

Note however that there is actually a larger number available on tmp in this case.

Solution:

Ignore the error, it is bogus.

Joomla failes component installation with SQL error

Issue:

Joomla 1.5 fails to install a component with the following error:
Component Install: SQL error or missing or unreadable SQL file. DB function reports no errors.

Solution:

The installer looks for the files within the admin files folder. This means that the files also have to be placed like standard files. Example xml config file:
<..>

sql/install.mysql.sql

<..>

Standard component name

sql/install.mysql.sql
<..>

<..>

Bea weblogic installation are jar files instead of binary

Issue:

The installation files as downloadable from Bea Weblogic are jar files instead of the executable files as mentioned in the installation manual.

Solution:

Use a different manual.
The important command is:
java -jar -mode=console

Bea Weblogic JMS fails to show in JNDI tree in cluster setup

Issue:

Bea Weblogic JMS information is not showing on any other machine in a cluster except the physical machine where the JMS is running.

Solution:

Bea implemented the JMS service standard as a high performance solution. To use this:
A JMS server has to be created per managed server (non-migratable);
The queues have to be created as (uniform) distributed queues with as target the cluster;
The connection factory also has to target the cluster.

Internet explorer does not show a div

Issue:

Unknown run time error in IE7 occurs while trying to put content in a div with javascript. No errors are to be seen in Firefox.

Solution:

Most likely a reserved keyword has been used as id for the div (like id=submit). Rename the div to another term, and the problem will most likely disappear.

dbms_output.put_line not visible in sqlplus

Issue:

While using dbms_output.put_line no output shows up at the console using sqlplus.

Solution:

Set serveroutput to on:
set serveroutput on
Now output will be visible

Using oracle plsql exceptions

Issue:

You have an custom exception you want to catch in plsql.

Solution:

Create a custom exception:
declare
MISSING_DATA exception;
PRAGMA EXCEPTION_INIT(MISSING_DATA, exception_number);
begin
begin
Your SQL;
exception when MISSING_DATA then dbms_output.put_line(' exception caught');
end;
end;
/

The important part is to set the correct exception_number:
Run your sql and see what exception oracle throws as first exception (ORA-12345). Replace exception_number with -12345.

EditFailedException in Bea Weblogic 9.1

Issue:

Bea Weblogic 9.1 fails during the change of configuration using the admin console (apply changes) with the exception: weblogic.management.provider.EditFailedException

Solution:

There is 2 possible solutions: First try the solution posted by Bea.

If this does not work, try the following:
Stop Bea (with most likely a kill -4). Assign more memory to Bea. Start Bea again. This might solve your issue.
Maybe a complete reboot of your environment will work too.

How to grow a Sequoia from seed

Issue:

You are trying to grow a Sequoia (giganteum) from seed (germination) and do not know how to do this.

Solution:

The shopping list:
- Buy standard plant soil at your local garden center;
- Buy breakable plastic pots, organic pots or be prepared to kill of your flower pot when the tree grows, diameter pot about 8 cm at the top;
- Buy a germination hothouse (about 20 cm high is a nice size) with some ventilation holes, and possibility to mount a light on it;
- Buy a small light (bulb/tube: Bulb if outside since it also gives sufficient warmth, 6 to 10 watts light is enough);
- Some aluminium foil for reflecting the light.

The planting:

1) Mount the lamp onto the hothouse;
2) Coat the inside of the hothouse bottom and the sides (until halfway the height of the hothouse) with aluminium foil=> Reflection increases the efficiency of the light, so 6 to 10 watts of light is enough;
3) Take the pots and fill them to the top with soil, do not compress the soil;
4) Add a generous amount of water to the soil;
5) Put some seeds on top of the soil (about 5 per pot);
6) Put very little (1 to 2 millimeter) soil on top of the seeds;
7) Add a bit more water;
8) Put the pot(s) into the hothouse;
9) Place the pots inside your house;
10) Plugin & turn on the light. Leave the light on for about 18 hours per day (longer is allowed unless it disturbs you).

About 2.5 to 3 weeks are between sowing the seeds and the first sequoia emerging using a surrounding temperature of about 15 to 20 degrees Celsius.

If the inside of the hothouse fogs up to much, you can clean it.

Occasional sunlight will help the process (and makes it possible for you to turn of the light)

Notes:

A small percentage of seeds really grows into tiny sequoias with even less of those surviving the first year. Expect about 25% to grow with this method.

Problem creating new groups in Joomla

Issue:

Extending group management in Joomla (1.0) does not seem to work with script from http://forum.joomla.org/viewtopic.php?f=231&t=257938.

Solution:

The table structure of the jos_core_acl_aro_groups changed slightly. The new script should look like:

SET @parent_name = 'Registered';

SET @new_name = 'Support';



-- Select the parent node to insert after

SELECT @ins_id := group_id, @ins_lft := lft, @ins_rgt := rgt

FROM jos_core_acl_aro_groups

WHERE name = @parent_name;



SELECT @new_id := MAX(group_id) + 1 FROM jos_core_acl_aro_groups;



-- Make room for the new node

UPDATE jos_core_acl_aro_groups SET rgt=rgt+2 WHERE rgt>=@ins_rgt;

UPDATE jos_core_acl_aro_groups SET lft=lft+2 WHERE lft>@ins_rgt;



-- Insert the new node

INSERT INTO jos_core_acl_aro_groups (group_id,parent_id,name,lft,rgt)

VALUES (@new_id,@ins_id,@new_name,@ins_rgt,@ins_rgt+1);

Oracle 11g installer fails

Issue:

The Oracle installer fails with the following error on SuSE 10.3:
java: xcb_xlib.c:52: xcb_xlib_unlock: Assertion `c->xlib.lock' failed

Solution:
The java based installer is not compiled on the local machine and is expecting certain libraries with a certain version. The comparison of these libraries can be relaxed by setting the following environment parameter:
export LIBXCB_ALLOW_SLOPPY_LOCK=0

Try to run the installer again. It should start.

proxy: No protocol handler was valid for the URL

Issue:

Page with an apache2 http proxy gives a 403 error using SuSE linux. The logfile shows:
[Sun Dec 16 18:46:20 2007] [warn] proxy: No protocol handler was valid for the URL /. If you are using a DSO version of mod_proxy, make sure the proxy submodules are included in the configuration using LoadModule.
[Sun Dec 16 18:46:20 2007] [warn] proxy: No protocol handler was valid for the URL /error/HTTP_FORBIDDEN.html.var. If you are using a DSO version of mod_proxy, make sure the proxy submodules are included in the configuration using LoadModule.

Solution:
Add the following to /etc/sysconfig/apache2:
APACHE_MODULES=".. proxy proxy_connect proxy_ftp proxy_http"
In which .. are the modules you already have in place.

java.lang.NoClassDefFoundError: javax/mail/Authenticator

Issue:

java.lang.NoClassDefFoundError: javax/mail/Authenticator in Tomcat while using javamail.

Solution:

Javamail contains a slight issue with locating the activation jar file from JAF.
Place the mail jars and activation.jar in tomcat/common/lib. This will solve the problem.

Problem installing PEAR

Issue:

You have a problem installing pear:
Installing PEAR environment: /usr/local/php5/lib/php/

Notice: unserialize(): Error at offset 255 of 987 bytes in phar://install-pear-nozlib.phar/PEAR/Config.php on line 1007

Fatal error: Call to undefined method PEAR_Error::getLayers() in phar://install-pear-nozlib.phar/index.php on line 66
make[1]: *** [install-pear-installer] Segmentation fault
make: *** [install-pear] Error 2

Solution:
Delete your pear.conf from where ever it is (usually /etc or your php $basedir/etc). It contains different data than expected by the installer, causing the installer to crash.

QMail delivers message many times after mailbox migration

Issue:
Qmail delivers message many times after migration from Plesk to vpopmail setup.

Solution:
Remove "|autoresponder" from .qmail configuration for the troubled user. The queue will than empty itself delivering the messages 1 last time.

Qmail bounces messages after mailbox migration

Issue:
Qmail bounces email after migration of some mailboxes (from Plesk to vpopmail setup).

The bounce mail from vpopmail:
Hi. This is the qmail-send program at xyz.com.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

:
This message is looping: it already has my Delivered-To line. (#5.4.6)

Solution:
You setting contains a forward which is not understood by the vpopmail setup of qmail. Replace the .qmail-default file content for this domain with:
| /home/vpopmail/bin/vdelivermail '' bounce-no-mailbox

Bea weblogic logrotate fails

Issue:

The logrotate of Bea Weblogic does not seem to work, while in the rotated files directory created by the admin, files are created. The logfiles just keep growing untill the disk is full.

Solution:
The issue is that Bea weblogic wants an absolute path in the configuration for the logrotate, but appearently can live with a relative path when writing to the logfiles itself. Replace all the paths to the logfiles and also to the rotation location with absolute paths, and the problem should be solved. Restart admin server to verify it works.

Pop-up Greybox frame with Flash

Issue:
Greybox provides pop-up frames by altering the href with javascript code. The onclick gets defined.
When wanting to use the same code from Flash, there are some problems with the transparancy of the greybox code.

Solution:
To get the greybox pop-up working correctly, call the javascript from flash with the following function (from greybox examples.html file):
getUrl("javacript:GBFlashCall(caption,url,height,width)");

In which you can set the caption, url, height and width yourself.
Add a script link in the header of you html file after the greybox files, also add the GB_ROOT_DIR, else it will not work:

Create the GBFlashCall.js file with the following content on the correct loction as defined in the