Spiralinks' Programmer's blog

Windows DHCP server problem on Xen VM hosts

2009-09-23T08:45:00.001-07:00

If your Xen hosted Windows DHCP server(s) are running on the same physical host as linux DHCP clients, then they will not receive a DHCP address.

Thanks to Loho, who quickly told me how to fix the problem - this is now solved. The trick is here (copied for posterity):

To work around this problem, turn off checksum offloading on the network adapter. To do this, follow these steps:

Click Start, click Run, type regedit, and then click OK.

Locate and then click the following registry key:

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters

In the right pane, make sure that the DisableTaskOffload registry entry exists. If this entry does not exist, follow these steps to add the entry:
1. On the Edit menu, point to New, and then click DWORD Value.
2. Type DisableTaskOffload, and then press ENTER.
Click DisableTaskOffload.
On the Edit menu, click Modify.
Type 1 in the Value data box, and then press ENTER.
Exit Registry Editor.

Useful BASH script - finding if any files exist from a wildcard

2009-09-07T04:42:00.001-07:00

This post has some details if you want to check if one or more files matching a pattern exist in a folder.

Specifically this is useful if you use

[ -f {pattern} ]

and the result contains more than one element - avoiding the error:

/usr/local/bin/{script}.sh: line x: [: too many arguments

The solution is something like the following:

files=$(ls {pattern} 2> /dev/null | wc -l)
if [ "$files" != "0" ]

Thanks for the post!

Oracle XE: Clearing out unwanted trace files

2009-08-14T02:37:00.000-07:00

If left unchecked, Oracle XE installations can balloon in size quite quickly - this is due to the trace files being written by the server. The following run in a cron script can be used to remove files more than 7 days old.

#!/bin/bash
find $ORACLE_HOME/../../../admin/$ORACLE_SID/bdump -name "*.trc" -mtime +7 -exec rm "{}" \;
find $ORACLE_HOME/../../../admin/$ORACLE_SID/udump -name "*.trc" -mtime +7 -exec rm "{}" \;
find $ORACLE_HOME/../../../admin/$ORACLE_SID/cdump -name "*.trc" -mtime +7 -exec rm "{}" \;

This tip was found and modified for XE in the following useful article 'Oracle Linux - Using the "find" command to manage files':

http://www.dba-oracle.com/t_unix_script_find_files_older_date.htm

Debian: apt-get interrupted, leaves files in bad state

2009-07-17T15:22:00.000-07:00

If you get the following error when running apt-get or dpkg on Debian / Ubuntu:

debconf: DbDriver "config": /var/cache/debconf/config.dat is locked by another process: Resource temporarily unavailable

Then the following commad will tell you what's using it:

fuser -v /var/cache/debconf/config.dat

Remote desktop 'Exceeded the number of connections' work-around

2009-05-21T05:17:00.000-07:00

You can optionally connect to the 'console' which is a screen 0 (by default screens 1 and 2 are the screens you connect to with a remote desktop client).This option is not in the Windows UI, you need to use the following command from Start->Run:

 mstsc -v:{machine address} /f -console

Windows Vista / Windows 7 use the syntax '/admin' rather than -console.

If you use a mac, you can put '/console' at the end of the machine name in the machine box.

If you use linux then add '-0' to the rdesktop command line.

Thanks to msalo and Kola Oyedeji for this information.

Keeping IE 6 (or 7) for development

2009-05-13T08:01:00.000-07:00

All,
If you are developing on IE6 and want to stop Microsoft automatic update from installing IE 7 or IE 8 please install the following updates from Microsoft:

Internet Explorer 8 blocker:
http://tinyurl.com/9yjpqw

Internet Explorer 7 blocker:
http://tinyurl.com/kwkgt

You need to run them to extract files, then go to a command prompt and run the command with a /B switch (block).

To keep IE6 you need to run both 7 and 8 blockers.

Then, you can keep your system completely up to date with old-school browsers!

HOWTO: Install 3ware 3dm2 on Ubuntu

2009-03-17T04:00:00.000-07:00

3dm2 is a very useful web management utility for 3ware's hardware RAID controllers.

This post finally gave me the clue, as there's no information on 3ware's site, and the installer simply fails if you try to run it on Ubuntu. Here it is in a nutshell:

Edit /etc/apt/sources.list

# Debian Unnoficial
deb http://ftp.debian-unofficial.org/debian stable main contrib non-free restricted

You will be warned about non-authenticated sources, but you can ignore this (can anyone tell me how to get the key for this site?)

Other notes:

By default, the site is only accessible from localhost (https://localhost:888/). To fix this, edit /etc/3dm2/3dm2.conf and set 'RemoteAccess' to 1.
The default password for User and Admin is '3ware'.

HOWTO: Build zaptel modules for Asterisk on Ubuntu

2009-02-06T05:49:00.000-08:00

Many people post about this, but I'm putting it here more for my future reference. A good pair of guides are here:

https://wiki.kubuntu.org/AsteriskOnUbuntu
http://codepoets.co.uk/linux_asterisk_setup_with_pstn_iax_and_sip

But, the long and the short of it is:

sudo m-a -t build zaptel
cd /usr/src
sudo dpkg -i zaptel-modules-{version}.deb
sudo modprobe zaptel
sudo modprobe {driver module e.g. wctdm}

Top 25 Website Errors

2009-01-14T05:30:00.001-08:00

We should look at all of these and think to see if we're doing the right thing to avoid them!

http://www.sans.org/top25errors/

Migrating Open Source Xen Windows Virtual Machines to XenServer

2008-12-10T09:05:00.000-08:00

This couldn't in fact be easier!

Download XenConvert from here (If this link expires, then it can be got from the Resource section of the XenServer download page).
Add a virtual disk to the guest machine (at least twice the size of the existing disk) to receive the exported VM.
Run the original guest machine and partition / format the new virtual disk (NTFS / FAT, as long as you can mount these filesystems in the host).
Install & Run XenConvert on the source guest machine.
Select 'XVA' and select the new virtual disk as the destination for the XVA image.
Shut down the source guest machine.
Work out where the new virtual partition starts - something like this:

root@eagle:/etc/xen# parted /dev/eagle-vm/act-XVA
GNU Parted 1.7.1
Using /dev/mapper/eagle--vm-act--XVA
Welcome to GNU Parted! Type 'help' to view a list of commands.
(parted) unit B                                                          
(parted) print                                                           

Disk /dev/mapper/eagle--vm-act--XVA: 26843545599B
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number  Start   End           Size          Type     File system  Flags
 1      32256B  26839088639B  26839056384B  primary  ntfs             

(parted)

Mount the new virtual disk - change 'offset' to be the value in the Start column above, replace ntfs with vfat if FAT32 was used:

mount -o ro,offset=32256 -t ntfs /dev/eagle-vm/act-XVA /mnt/t

Copy the *.xva folder from this mounted drive to somewhere accessible to the new XenServer host.
Run XenCenter on a machine and connect to the new host.
Import a new VM, select the ova.xml file from the *.xva folder, and follow the import - you'll need to setup a new Network Interface.
If required, reactivate Windows on the new guest as it starts up, and install XenServer Tools.

JBoss clustering

2008-10-21T07:42:00.001-07:00

A guide is on the JBoss website. The application doesn't yet cluster - more later!

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Oracle: Creating indexes for unindexed foreign keys

2008-10-01T05:05:00.001-07:00

This script searches for unindexed foreign keys and outputs a 'create index' script for those keys.

It will pick up unindexed views, and obviously these can't have indexes so you will see an error when running the generated script.

References: Script taken from here, via this article.

column columns format a20 word_wrapped
column table_name format a30 word_wrapped

create sequence indexname_seq start with 1 increment by 1;

select 'create index FOREIGN_KEY_IX' || indexname_seq.nextval || ' on ' || q.table_name ||
'(' || q.c1 || ');' from (

select decode( b.table_name, NULL, '****', 'ok' ) Status,
       a.table_name, a.columns c1, b.columns c2
from
( select substr(a.table_name,1,30) table_name,
        substr(a.constraint_name,1,30) constraint_name,
         max(decode(position, 1,     substr(column_name,1,30),NULL)) ||
         max(decode(position, 2,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position, 3,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position, 4,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position, 5,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position, 6,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position, 7,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position, 8,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position, 9,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position,10,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position,11,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position,12,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position,13,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position,14,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position,15,', '||substr(column_name,1,30),NULL)) ||
         max(decode(position,16,', '||substr(column_name,1,30),NULL)) columns
    from user_cons_columns a, user_constraints b
   where a.constraint_name = b.constraint_name
     and b.constraint_type = 'R'
   group by substr(a.table_name,1,30), substr(a.constraint_name,1,30) ) a,
( select substr(table_name,1,30) table_name, substr(index_name,1,30) index_name,
         max(decode(column_position, 1,     substr(column_name,1,30),NULL)) ||
         max(decode(column_position, 2,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position, 3,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position, 4,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position, 5,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position, 6,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position, 7,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position, 8,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position, 9,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position,10,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position,11,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position,12,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position,13,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position,14,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position,15,', '||substr(column_name,1,30),NULL)) ||
         max(decode(column_position,16,', '||substr(column_name,1,30),NULL)) columns
    from user_ind_columns
   group by substr(table_name,1,30), substr(index_name,1,30) ) b
where a.table_name = b.table_name (+)
and b.columns (+) like a.columns || '%') q
/

drop sequence indexname_seq;

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Enabling Load Balancing on JBoss

2008-09-23T03:21:00.001-07:00

JBoss won't load balance with mod_jk or IIS without the following settings modified (see this RedHat doc):

{JBOSS_HOME}/server/{SERVER_NAME}/deploy/jboss-web.deployer/server.xml

<Engine name="jboss.web" defaultHost="localhost" jvmRoute="{NODE_NAME}">
... ...
</Engine>

Where '{NODE_NAME}' is the name of the jk worker from jk-workers.properties.

{JBOSS_HOME}/server/{SERVER_NAME}/deploy/jboss-web.deployer/META-INF/jboss-service.xml

<attribute name="UseJK">true</attribute>

If this isn't set then sticky sessions will fail to work, and you'll lose your session state between requests.

You also need to be aware that the 'domain' parameter needs to be set in the jk-workers.properties file, like this example:

worker.list=jkstatus, ajp-lb

worker.jkstatus.type=status

worker.node-1.port=8009
worker.node-1.host=node-1.spl.com
worker.node-1.type=ajp13
worker.node-1.lbfactor=1
worker.node-1.cachesize=10
worker.node-1.domain=ajp-lb
# Define preferred failover node for worker 1
#worker.node-1.redirect=node-2

worker.node-2.port=8009
worker.node-2.host=node-2.spl.com
worker.node-2.type=ajp13
worker.node-2.lbfactor=1
worker.node-2.domain=ajp-lb
worker.node-2.cachesize=10
# Disable node-2 for all requests except failover
#worker.node-2.disabled=True

worker.ajp-lb.type=lb
worker.ajp-lb.balanced_workers=node-1,node-2
worker.ajp-lb.sticky_session=true

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New method for DB schema statistics generation

2008-09-18T06:07:00.001-07:00

I have removed the comment from the db post about the dbms_utilty.analyze_schema command as it has apparently been superseded in 10g (since 8i in fact) with the command below:

EXEC DBMS_STATS.gather_schema_stats (ownname => '{{SCHEMA}}', cascade =>true,estimate_percent => dbms_stats.auto_sample_size);

Thanks to Todd at Datapipe for this info

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Java HashMap.keySet return value

2008-09-17T07:52:00.001-07:00

I came across this when trying to add the set of keys in a HashMap to a J2EE session.

HashMap.keySet() returns a Set of type HashMap$KeySet which extends AbstractSet. It IS NOT Serializable.

So, you can't add it to a distributable session, which is annoying.

I've filed a bug w/ Sun to fix this, in the meantime if you need to set a session attribute with the result of keySet() use:

session.setAttribute("blah", new HashMap(map.keySet()));

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Intellij IDEA on Ubuntu Hardy 64-bit

2008-08-16T09:47:00.001-07:00

If you see 'Too Many Open Files' or 'The JDK is corrupt' errors running IDEA 7.0.4 on Hardy then this can be fixed by editing the file 'bin/idea.vmoptions' to remove the '-ea' flag. Not sure why this is there by default, but it shouldn't be.

Another useful thing to do is add '-d64' to enable the 64-bit HotSpot VM.

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Remote Debugging JBoss with JConsole

2008-08-13T02:21:00.001-07:00

In order to monitor the memory, stack and object usage within a running JBoss application, do the following:

Unix: add the line:
JAVA_OPTS="$JAVA_OPTS -Dcom.sun.management.jmxremote"
to $JBOSS_HOME/bin/run.conf
and run JConsole on the local machine ($JAVA_HOME/bin/jconsole)

Windows: add the line:
set JAVA_OPTS=-Dcom.sun.management.jmxremote %JAVA_OPTS%
to %JBOSS_HOME%\bin\run.bat
and run JConsole on the local machine ($JAVA_HOME\bin\jconsole.exe)

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Remote Debugging with JBoss and IDEA

2008-08-13T02:08:00.001-07:00

In order to debug jboss - i.e. put in breakpoints, etc, JBoss needs to be started in debug mode. This can be done as follows:

Unix: uncomment the line:
JAVA_OPTS="$JAVA_OPTS -Xrunjdwp:transport=dt_socket,address=8787,server=y,suspend=n
in $JBOSS_HOME/bin/run.conf

Windows: uncomment the line:
set JAVA_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,address=8787,server=y,suspend=y %JAVA_OPTS%
in %JBOSS_HOME%\bin\run.bat

Then, you need to configure IDEA for debugging, which can be done by Editing the Run Configurations, then adding a 'Remote' server.
set the 'Port' entry once it is created, and give it a name. If necessary set 'Host' to the remote jboss host.
Ensure that 'Make' is checked 'Before Launch'

The hard work is now done; run JBoss on the command line of the remote server, then select the new Run Config, and click Debug.

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Oracle SQLPlus arrow keys on Linux

2008-07-25T02:19:00.000-07:00

This blog post shows how to get arrow keys working properly on linux-based systems in SQLPlus. In a nutshell, run this as the SQLPlus user:

sudo apt-get install rlfe
echo "alias sqlplus='rlfe sqlplus'" >> ~/.bashrc
source ~/.bashrc

Then run SQLPlus normally

Using Chainsaw with JBoss

2008-07-14T11:51:00.001-07:00

To use Chainsaw to debug applications on JBoss edit the file jboss/server/{server}/conf/jboss-log4j.xml as follows:

Add the following to the top of the file, below the other <appender/> entries:

<appender name="SOCKET" class="org.apache.log4j.net.SocketAppender">
        <param name="remoteHost" value="localhost"/>
        <param name="port" value="4445"/>
        <param name="locationInfo" value="true"/>
</appender>

And add the following to the bottom of the <root/> entry (below the other appender-ref lines):

<appender-ref ref="SOCKET"/>

Run chainsaw from here and create a default (old style) listener on port 4445.

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Enabling external access to jboss

2008-07-14T09:50:00.001-07:00

JBoss 4.2.x doesn't by default allow external network access. To allow access from anywhere, add '-b 0' to the run.sh command line.

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Cloning linux VMs

2008-06-26T05:02:00.001-07:00

Steps for cloning linux VMs under Xen:

Create snapshot of source VM: lvcreate -s -n {snap name} -L {snap size} {vg path}
Create destination LV and copy: dd if={snap path} of={dest LV path} bs=10M
Copy xen config file.
Edit file, rename vm, change disk paths and comment mac= in vif (i.e. vif=[ '' ]).
xm create -c {vm name}
Once booted, sudo rm /etc/udev/rules.d/*persistent-net.rules
Edit /etc/network/interfaces and ensure network interface is set to eth0
Then remove SSH host key: sudo rm /etc/ssh/ssh_host_{dsa,rsa}_key*
And regenerate it: sudo dpkg-reconfigure -plow openssh-server
Modify hostname: sudo vi /etc/hostname
Reboot vm
Check MAC address of eth0 (ifconfig)
Paste MAC into vif = [ 'mac={}' ] of VM config file
Reboot vm, verify IP address has changed

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Disabling directory listings in tomcat

2008-03-20T05:56:00.000-07:00

This article is useful. Among other things it shows how to disable directory listings (which are on by default) on Tomcat.

Seagate FreeAgent Drives on Linux

2008-03-10T06:18:00.000-07:00

If you've bought a Seagate FreeAgent drive with a view to running it on Linux, be aware that it won't work out-of-the-box. In fact, we bought one, then I sent it back for RMA, only to find the same issue with the new replacement.

The issue is that after about 1min of use the drive spins down and closes the USB connection, causing mounts to fail and the device to be unusable.

It turns out that the drives include some cunning/annoying (delete as applicable) power saving logic which only correctly works in Windows. The solution, as a number of posts mention is to run the following command (or more cunningly put this command in the hotplug subsystem so it's always run on connection):

sdparm -clear STANDBY -6 /dev/sdX

SQL Server Express Management Studio 2005 backups of MSDE databases

2008-03-06T05:38:00.000-08:00

If you try to take a backup of a MSDE database with SQL Server 2005 Management Studio then it fails with the message 'Property Backup Directory is not available for settings...'. This link talks about the reason why - a missing registry entry.

The key is KEY_LOCAL_MACHINE\Software\Microsoft\MSSQLServer\MSSQLServer pre SP4. Add BackupDirectory value = c:

For MSDE SP4 however, it seems that this registry location has changed - to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSDE\MSSQLServer Adding the BackupDirectory value = c: worked for me.

Installing JBoss 4.2.1.GA as a service

2008-02-29T06:45:00.001-08:00

The JBoss wiki now recommends JavaServiceWrapper as the installation method of choice for running JBoss as a service on Windows, and it seems to work well. Follow the instructions on the Wiki page. I've modified the config slightly as follows:

wrapper.java.command=%JAVA_HOME%/bin/java

wrapper.java.mainclass=org.tanukisoftware.wrapper.WrapperSimpleApp

wrapper.java.classpath.1=%JBOSS_HOME%/lib/wrapper.jar
wrapper.java.classpath.2=%JAVA_HOME%/bin/java/lib/tools.jar
wrapper.java.classpath.3=./run.jar

wrapper.java.library.path.1=%JBOSS_HOME%/lib

# these are the JAVA_OPTS
wrapper.java.additional.1=-server
# enviroment variables - define the ones that match your desired environment
wrapper.java.additional.2=-Denviromnment.variable=value
# memory parameters - define the ones that match your desired environment
wrapper.java.additional.3=-Xms256m
wrapper.java.additional.4=-Xmx768m
# If you need serialization suppport
wrapper.java.additional.5=-Dsession.serialization.jboss=true

wrapper.app.parameter.1=org.jboss.Main
# Parameters to be passed to the application (Jboss)
# Define server name (configuration) - If you need a config that is different than the "default" or need to run multiple configs
#wrapper.app.parameter.2=-c default
# Define listening IP - If you have more than one IP or want to indicate to listen on a specific IP
#wrapper.app.parameter.3=-b aaa.bbb.ccc.ddd
# wrapper log location
wrapper.logfile=%JBOSS_HOME%/server/DEFAULT/log/wrapper.log

# You must not change below parameters without first uninstall the service
# service name
wrapper.ntservice.name=JbossDEFAULT
# service display name
wrapper.ntservice.displayname=JBoss Server DEFAULT

Change 'DEFAULT' where necessary and enable wrapper.app.parameter.2 if you're using a different server configuration.

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Gutsy install - libnss-ldap authentication

2008-01-31T01:40:00.001-08:00

Steps to complete a reliable libnss-ldap authentication setup:

apt-get install libnss-ldap
Select 'No' to debconf configuration
Use defaults (we're going to trash them soon anyway)
rm /etc/ldap.conf
ln -s /etc/ldap/ldap.conf /etc/ldap.conf
Update /etc/ldap.conf:
suffix "dc=spl.com,o=top"

uri ldap://{server1}:389/ ldap://{server2}:389/
pam_password exop

ldap_version 3
pam_filter objectclass=posixAccount
pam_login_attribute uid
nss_base_passwd ou=People,dc=spl.com,o=top
nss_base_shadow ou=People,dc=spl.com,o=top
nss_base_group ou=Groups,dc=spl.com,o=top
nss_base_hosts ou=Hosts,dc=spl.com,o=top

bind_policy soft

scope one

nss_reconnect_tries 1
nss_reconnect_sleeptime 1
nss_reconnect_maxsleeptime 8
nss_reconnect_maxconntries 2
cp /etc/nsswitch.conf /etc/nsswitch.conf.noldap
Add ldap [UNAVAIL=return] to the end of passwd, group, shadow lines
cp /etc/nsswitch.conf /etc/nsswitch.conf.ldap
Edit new file /etc/network/if-down.d/nsswitch-noldap
#!/bin/bash
cp /etc/nsswitch.conf.noldap /etc/nsswitch.conf
Edit new file /etc/network/if-up.d/nsswitch-ldap
#!/bin/bash
cp /etc/nsswitch.conf.ldap /etc/nsswitch.conf
chmod +x both the files created above
Add:
account sufficient pam_ldap.so debug
above the first real line of /etc/pam.d/common-account
Add:
auth sufficient pam_ldap.so debug
above the first real line of /etc/pam.d/common-auth
Add:
password sufficient pam_ldap.so debug
above the first real line of /etc/pam.d/common-password
(For auto-creation of home dirs) add:
session required pam_mkhomedir.so skel=/etc/skel/
Between the 2 real lines of /etc/pam.d/common-session
Reboot and CHECK ALL IS WELL before relying on the server. Bad symptoms include long time to boot, udev errors and login timeouts... If necessary edit the grub boot string, adding 'single' to the end of the kernel parameters and remove the above changes before seeking advice...

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Thunderbird installation woes

2008-01-21T02:20:00.000-08:00

<Thanks to Andrew for his time frustration and perseverance in getting a solution here!>

If you are running Thunderbird 1.5 xx, you are probably going to get an upgrade forced on you whether you want it or not. The upgrade will fail. So you try to upgrade to v2.0.0.9, the current release. It will fail. (do they even pretend to test this stuff?)

Go to the Thunderbird directory, rename mozMAPI.dll (to .bak or whatever). Try re-installing Thunderbird. It will work.

JBoss port numbers

2008-01-04T02:06:00.000-08:00

The link above is a very useful page outlining the port numbers used by JBoss and where to configure them. In case the page dies, here's a copy of the useful bit - the table...

File	Service	What	Parameter	Port	NewPort
deploy/http-invoker.sar/META-INF/jboss-service.xml	Tomcat		InvokerURLSuffix	8080	11080
deploy/jboss-ws4ee.sar/META-INF/jboss-service.xml	Tomcat		WebServicePort	8080	11080
			WebServiceSecurePort	8443	11443
deploy/jbossweb-tomcat55.sar/server.xml	Tomcat	HTTP	port	8080	11080
		HTTP	redirectPort	8443	11443
		AJP	port	8009	11009
		SSL	port	8443	11443
conf/jboss-service.xml	JBoss	WebService	Port	8080	11080
		Naming	Port	1099	11099
		Naming	RmiPort	1098	11098
		invoker,type=jrmp	RMIObjectPort	4444	14444
		invoker,type=pooled	ServerBindPort	4445	14445
deploy/jms/uil2-service.xml	JMS		ServerBindPort	1093	11093
deploy/hsqldb-ds.xml	HSQLDB	Hypersonic	Port	1701	11701
deploy/cache-invalidation-service.xml			ProviderUrl	1099	11099

Removing SQL Server

2007-11-09T01:58:00.000-08:00

This blog post provides very useful guidance on how to get rid of pesky SQL Server installations.
However, a couple of additions:

Ensure you are running the command prompt in priviliged mode before trying the smartmsizap tool.
You may have to manually stop services, then remove the Microsoft SQL Server directory in c:\program files\ after these steps.
There will still be a few residual bits in the Registry - do a search for 'SQL Server' and nuke them also.

Meet the team

2007-10-12T20:12:00.000-07:00

Not a serious blog here, but as the team have been feeling photogenic this week I thought I'd post a few pictures...

Oracle XE Default HTTP Port and listen on address

2007-09-24T05:03:00.000-07:00

To change the default Oracle XE HTTP Listening port (8080), just run the following from sqlplus as sysdba:

exec dbms_xdb.sethttpport(NEW_PORT_NUM);

Useful for when it conflicts with default jboss/tomcat ports.

By default, it only listens on localhost. You can modify this by going to the homepage (will require a browser, or SSH tunnel to that machine)

Java 1.5 'static import' feature

2007-09-21T09:56:00.000-07:00

A neat new-ish Java feature, which I just stumbled upon:

The static import construct allows unqualified access to static members without inheriting from the type containing the static members. Instead, the program imports the members, either individually:

import static java.lang.Math.PI;

or en masse:

import static java.lang.Math.*;

Once the static members have been imported, they may be used without qualification:

double r = cos(PI * theta);

Installing MSDE 2000

2007-09-19T10:52:00.000-07:00

Run the installer, decompress the MSDERelA directory to somewhere (not c:\mssql)
Open a command window to this directory, and enter the command-line shown below to run the installer in silent-mode.
The log file for the installation is written into a file named setup.log within the current working directory. You can place the file any where you want by updating the pathname noted after the /L*v switch.
Since the installation runs silently without reporting errors, you must open the log file after setup completes to check for a successful status at the end of the file.

setup sapwd="{PASSWORD}" securitymode=sql
datadir="{DATA DRIVE}\mssql\data"
targetdir="{INSTALL DRIVE}\mssql"
disablenetworkprotocols=0 instancename="{INSTANCE}" /L*v setup.log

UPDATE 4-MAR-2008:

SP4 is now available for MSDE - this can be downloaded from here. Be sure to download the MSDE version, the run the installer to decompress the setup files.

Note that this is not an upgrade, rather the full version of the installer so do not follow the instructions above with the MSDERelA installer, instead start in the folder generated by the SP4 decompression.

Oracle useful management commands

2007-09-19T09:32:00.001-07:00

Delete duplicate rows (thanks to http://www.devx.com/tips/Tip/13943)

delete {table}
where rowid not in
  (select min(rowid) from {table}
    group by {columns});

Where {columns} are index column(s) (comma-separated)

Copy a table's contents into a new table (thanks to http://www.ilook.fsnet.co.uk/ora_sql/sql_01.htm)

CREATE TABLE BOOK_COPY AS
SELECT * FROM BOOK

Kill user sessions (thanks to http://www.adp-gmbh.ch/ora/sql/alter_system.html#kill_session)

Get session ID & session serial:

select username,sid,serial#,schemaname from v$session;

-- add "where schemaname='{schema}'" to the end if you want to filter by schema

Kill session(s)

alter system kill session '{sid},{serial#}'

Modify sys/system users and passwords

sqlplus / as sysdba
alter user sys identified by <NEW PASSWORD>

Create tablespace

create tablespace {name} datafile
'/home/oracle/databases/ora10/{name}.dbf'
size                                  10M
autoextend on maxsize                200M
extent management local uniform size  64K;

Note: For XE the path to the DB files is: /usr/lib/oracle/xe/oradata/XE

List all available users

SELECT username FROM all_users ORDER BY username;

Change Oracle XE's XML DB default port (8080)

call dbms_xdb.cfg_update(updateXML(
         dbms_xdb.cfg_get()
       ,
       '/xdbconfig/sysconfig/protocolconfig/httpconfig/http-port/text()'
       , 8081))
  /

Useful DB-related snippets

Backup the db on SQL01:

Change dir to ~/data-backup

exp {user}/{password} file={user}_{YYYYMMDD}.dmp

ZIP all DMP files in a folder (unix / cygwin)

find -name "*.dmp" -exec zip -9 "{}".zip "{}" \;

Move all indices to a different tablespace

SET PAGESIZE 0
spool c:\index_build.sql
CREATE 'ALTER INDEX '||index_name||' REBUILD
TABLESPACE <tablespace_name>;' from user_indexes;
spool off

Run a script:

sqlplus {user}/{password}
@@{scriptname}.sql

Drop & Recreate a user:

sqlplus system/{sys-password}
DROP USER {user} CASCADE;
CREATE USER {user} IDENTIFIED BY {password}
DEFAULT TABLESPACE {tablespace};
GRANT CONNECT,RESOURCE,DBA TO {user};

Import a dump file (full - normally preceeded by a user drop & recreate / partial):

imp {user}/{password}file={filename}.dmp
fromuser={fromuser} touser={user}

If you encounter an ORACLE 12560 error (TNS Protocol), try this:

set ORACLE_SID={SID} e.g. set ORACLE_SID=spldev01

SQL Server user fix

2007-09-19T08:58:00.000-07:00

This is very useful after a restore of a DB to reassign the correct system user to the db user:

sp_change_users_login 'Update_One',
'{db user}','{sys user}'

SQL check for duplicates

2007-09-19T02:55:00.000-07:00

Search for duplicate entries in a table that is supposed to have unique whatevers (Departments in this case)

select distinct deptid, count(*)
  from ps_dept_tbl
  group by deptid
    having count(*) > 1

Fixing Windows Vista

2007-09-11T02:34:00.001-07:00

So I've been bugged for about 2 months now as to why my Vista install on my laptop refuses:

To run Windows Media Player.
To do much interactive stuff in Internet Explorer.
To open the 'Extended' view in the Services control panel.

Well, I've found the answer thanks to this post. It seems that some installation somewhere (I blame OneCare, but this blame is frankly unfounded) has unregistered the VB and Java script DLLs on the system, both of which it seems are required to run WMP and display funky folder properties, etc. There's a simple fix:

regsvr32 jscript.dll
regsvr32 vbscript.dll

So congratulations to the post writer, and I now don't need to reinstall my tablet; that is, if I can get my shiny new T-Mobile 3g modem working!

SVN Performance Fix

2007-08-17T07:27:00.001-07:00

Nearly forgot to post about this one! A few weeks back I made some changes to the apache conf files which are what resulted in our SVN performance increase. Specifically, the addition of the

SVNPathAuthz off

directive. The reason this helps so much is simple enough: apparently, mod_dav_svn spends a ridiculous amount of time ensuring/enforcing per-directory path authentication restrictions. Since we have none of these restrictions in place at any rate, this option is irrelevant - and thus can be disabled!

Returning a table from a function in Oracle

2007-08-14T13:32:00.000-07:00

This is a great article on how to create a function which returns mutliple values.

Windows Symlinks

2007-08-09T07:51:00.000-07:00

It turns out NTFS has supported *nix-esque "symlinks" for a while.

It's easily accessible in Vista using the mklink command, however this same functionality can [essentially] be added to Win 2K/XP by using this neat sysinternals tool:

http://www.microsoft.com/technet/sysinternals/FileAndDisk/Junction.mspx

Very useful, esp. for linking "spldev" in a branch to its real location (saves you from copying it in every time..)

MultiTouch Demo

2007-08-08T05:11:00.000-07:00

This is insane - if you thought the iPhone was revolutionary - think again! Jeff Han has been demoing this stuff at TED for years. Here's his latest demo from his new company Perceptive Pixel:

http://link.brightcove.com/services/link/bcpid607757611/bctid422563006

I admit, this isn't particularly related to Spiralinks in any fashion.. But it's just so damn neat I couldn't pass up the opportunity to share it with you here :-)

Wonderful Java presentations

2007-08-07T06:16:00.001-07:00

This is a wonderful presentation series from the guys at Sun on Java. It turns out that in programming - as in life - there is sometimes much more going on than meets the eye. :-)

http://video.google.com/videoplay?docid=9214177555401838409&q=Advanced+Topics+in+Programming+Languages%3A+Java+Puzzlers&total=2&start=0&num=10&so=0&type=search&plindex=0

Be warned though - each presentation is over an hour long, and once you start I almost guarantee you won't be able to stop watching.

Anonymous class initialization

2007-08-07T04:59:00.000-07:00

Easy way to define an initializer (psuedo-"constructor") within an anonymous class:


c.addActionListener(new ActionListener() {
  {
      // initialize something
  }

  public void actionPerformed(ActionEvent e) {
      // handle action
  }
});

Java inheritance magic

2007-08-06T03:55:00.000-07:00

I've been bugged for a long time by not being able to access superclass methods in an inner class. And it turns out that it's dead easy to do - if you know how:

{ParentClass}.this.{function}

Hibernate 'instance associated with more than one sessions'

2006-07-25T09:09:00.000-07:00

Argh! This (perfectly reasonable) error occurs quite frequently when building multi-threaded swing applications such as the admin tool.

I've created a useful debugging tool for this kind of thing in my HibernateUtil session factory:


private static HashMap allSessions = new HashMap();
public static Session currentSession(String identifier) {
<snip>
    allSessions.put(getThreadId(identifier), s);
<snip>
}
private static String getThreadId() {
    return Thread.currentThread().getName();
}
public static String findObject(Object ob) {
    String ret = "Object \"" + ob.toString() + "\" is in: ";
    HashMap h = (HashMap) session.get();
    Iterator it = allSessions.entrySet().iterator();
    while( it.hasNext() ) {
        Map.Entry cur = (Map.Entry) it.next();
        if( ((Session) cur.getValue()).contains(ob) )
            ret += cur.getKey() + ", ";
    }
        return ret;
}

Tora on Ubuntu

2006-06-15T03:59:00.000-07:00

This was stolen from CERN's hints and tips but modified:

Ensure that you have the instant client from www.oracle.com - and also install the SDK files.

Use apt-get to install the latest tora source package and the needed libraries :

apt-get install kdelibs4-dev kdebase-bin libqscintilla-dev
cd 
apt-get source tora
cd tora-1.3.21

Now modify the debian/rules file : you have to remove the --without-oracle in the line that contains configure :

vim debian/rules
/--without-oracle
Remove it and save
Add --with-oci-version=10 to the end of the same line
Add exports for LD_LIBRARY_PATH and ORACLE_HOME to the top of this file

In the instantclient directory run:

ln -s . lib

Now compile :

dpkg-buildpackage -us -uc -rfakeroot

This results in the following packages in /usr/src :

tora_1.3.21-1_i386.deb

And install :

dpkg -i ../tora_1.3.21-1_i386.deb

Last point if you don't want dselect to update the package when you do a full update, just mark it with an '=', or use synaptic to lock the package version.

HTTP NTLM Authentication with jCIFS

2006-04-28T05:09:00.000-07:00

Well, finally worked out what was going wrong with this on our client site...

You _don't_ need to enable authentication with the IIS server; the jcifs installation does all the negotiating for your; enabling IIS means that the default domain is incorrect, and so the authentication fails; every time.

So, it's sorted, at last!

I'll put more detailed info here if I can be bothered later.

DNS DDOS attack warning

2006-04-03T08:19:00.000-07:00

My ISP just warned me that my site was an Open Recursive DNS Server...

I looked into it, and it is true, by default, NetMax is. The solution is to add a firewall rule that drops all NEW/INVALID connections with dest port 53.

Hopefully this will also clear up the issue that we were having with named on NetMax falling over from time to time...

HTTP NTLM Authentication with jCIFS

2006-04-03T08:16:00.000-07:00

Well, jCIFS really works!

Installed a test .war file on our client's Windows 2003 domain and once we'd cleared up whether to use a domain name, or a domain server name (The latter if you don't use WINS), it worked - out of the box, just like that - as a Servlet filter.

Very good stuff - I recommend you check it out!

Clustering on JBoss

2006-03-28T00:43:00.000-08:00

Well, I've finally (thanks to Ron Schmalz) worked out a solution - as yet untested - for the session management nightmare.

The answer lies in an HttpSessionListener; basically the 'Session Factory' that was created with nasty static members for sessions becomes a listener, and on create / destroy, an 'SPL Session' is created with the real HttpSession object so that all comes good with session replication - hopefully! Watch this space for the results...

Clustering on JBoss

2006-03-27T09:46:00.000-08:00

It seems I'm now an expert at clustering on JBoss...

Unfortunately the application uses static member variables rather than container-managed sessions to store 'session' attributes.

I'm trying to work out how to get the container session from the string session ID. Not sure that this is possible due to the security restrictions on the container, but am still looking...