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Showing posts from 2006

Java 5 crash - the saga continues

It really seems to be a problem related to the GC options mentioned here. However there seems to be more to it. With the rather aggressive setting of only 6 seconds between full GCs we were able to reproduce the problem, however only on a very specific combination of hardware, OS and Java VM.Running on RedHat 9 with Sun's Java VM 1.5.0_09 we could only see the problem on one machine that appears to be the same as all the others we use. However as this very same machine shows no problems at all when running our application with Java 1.4.2_08 or 1.6.0RC - even with the 6 seconds interval - I do not believe in faulty hardware.I removed the machine's hard drive and put it into an identical system (as far as we can see and are told by its manufacturer). In that box (and two more I tried) I cannot get any crash with either Java 1.4, 1.5 or 1.6. Strangely enough even the drive from one of those other machines mounted into the problematic box showed no problems. We really do not have …

Some progress on Java 5 on Linux crash

In two previous posts (first here and second here) I reported about Java 5 VM crashes on Linux machines.Digging deeper into the problem with external support led to some new evidence. Apparently the problem is in some way related to regular garbage collects initiated by the so called "GC Daemon" thread. It gets spawned when you use some fashion or other of RMI and calls full GCs in order to get rid of unreachable remote objects.One can specify the interval (in milliseconds) between calls to the garbage collector using -Dsun.rmi.dgc.server|client.gcInterval. With our application using RMI to call remote services we reduced this value to as little as 6 seconds. As we expected this let us reproduce the problem we have much more often than before. In 4 days we observed 8 VM crashes, each of them with very similar hs_err files.This means that my test program might have revealed even another bug, because it did produce some crashes, however it does not use anything connected with …

Follow Up: F-Secure's response

Not too long ago I wrote about a problem concerning F-Secure Anti-Virus 2007 and the Kerio Personal Firewall in this article. At the end of it I said I would inform F-Secure about the problem. I did and this is about their response.On November 13th I used the support form on F-Secure's website (Germany) to report to them the problem I had experienced. My report was about 2K long (I still have it) and included precise information about the situation, what I had found out and what to do to prevent it. I suggested having the installer issue a warning concerning 3rd party personal firewalls, especially since those seemed to be no problem with the 2006 version. I also included a link to my even more verbose blog post.On November 14th I got a response from one of their support agents. Apart from a lengthy auto-generated intro on how to issue correct problem reports (comes with every mail, does not have anything to do with your individual request) I got a very brief answer (I translated …

Java 5 crashes on Linux 2.6, too

Two and a half weeks ago I published a post about problems with random VM crashes using Java 5 on Linux with a 2.4 kernel.Most of the feedback I got suggested upgrading to a more recent kernel version. Because this represents a major undertaking for our application (several thousand clients deployed with Java 1.4.2 on RH9) we needed to be sure this would work.Because all the crash reports - see the original post - seemed to hint into the GC's direction I wrote a little test application to stress the garbage collector. What it does is to create a configurable number of threads, each of which just allocates a byte[] of variable size. In case an OutOfMemoryError occurs, the thread gets replaced with a new one. You can find the code at the bottom of this post.I started 4 instances of this tool under Ubuntu 6.06, each configured with 20 threads (first parameter) and up to 40MB of memory per thread (second parameter, in bytes).After 4 days of continuous running - we had just started to …

Amazingly simple - Collection Initialization

On Todd Huss' blog I just came about a very simple way of initializing a collection with a set of predefined values. It is so simple that it is amazing people do not use it way more often. For my part, I have seen this use of instance initializers for the first time, although they are nothing sooo special...

MySQL/InnoDB slowness with Blobs

Reading about Peter Zaitsev's feature idea about Finding columns which a query needs to access - which I would really like to see implemented - reminded me of a bug report I filed in 2004 and which bit me again only a few days ago. You can find it under Bug #7074 in the MySQL bug tracking tool. Although it is filed as a feature request, I think one should be aware of this, as it may cause problems in your applications (it did in ours).Basically it is about explicitly specifying which columns you need in a result set, instead of just using SELECT *. This is generally a good idea, however if the table contains BLOB columns, it becomes even more important, as it may affect performance heavily in an unexpected manner.From the bug report:MySQL first reads all the selected columns, and only after that checks the WHERE.This may lead to long running queries, even if you do not use the BLOB column in the WHERE clause and even if there is no data to retrieve based on the query conditions.Fo…

System Lockup: F-Secure AV 2007 and Kerio Firewall

Recently I received a notification about F-Secure Anti-Virus 2007 being available. As an F-Secure customer you are entitled to upgrade from the 2006 version if your subscription is valid. So I downloaded the installation package and performed the upgrade.After the obligatory reboot things started to fall apart. My computer would not respond for more than about 30 seconds after I had logged in. Opening the Start menu would work, maybe even opening e. g. the Control Panel sub menu. However nothing else would work after this point. Using Ctrl-Alt-Del to get the Task Manager just allowed me to "wipe" the start menu from the screen, no more action would be possible.What made me suspicious was a little dialog I had to dismiss right after logging in that informed me about my Kerio Personal Firewall not being found by the system-tray GUI. Because conflicting firewalls are known to cause lockup problems like this, I originally bought F-Secure Anti-Virus instead of the whole Internet …

JavaPosse podcast on Java GPL'ing

They guys of the JavaPosse have just released a special issue of their podcast in which they interview Mark Reinhold (chief engineer for Java SE), Rich Sands (community marketing manager for Java SE) and Eric Chu (senior director of the Client Systems Group and head of its Java ME initiatives).Dick wall posted a story on Digg.com called Questions about Open Source Java? This Podcast may have the answers! which leads to the podcast. Very interesting stuff, especially concerning the famous question "Will my app have to become Open Source, too, if I use Sun's Java?".Be sure to cast your vote for the item on digg.com :)

Vista Aero and QuickTime

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Very cool behaviour of QuickTime on Vista (ok, RC1, but I do not think this will become better):This is shown when you start the QuickTime control panel applet. Notice that the publisher information is displayed as "Microsoft Windows Publisher", so you have no idea that this was really the QuickTime applet. It could have been any other process in the background, too.

Java 5 random VM crashes

We are currently evaluating the consequences of migrating our application from Java 1.4 to Java 5. While initial tests revealed only simple issues (like variables called enum etc.) we are now seeing a much more severe problem: Random VM crashes.Currently we only see this on Linux (Kernel 2.4) only, however even there we cannot reliably reproduce the problem. On a single machine we have seen two crashes in a week. Notably the application was not being used, it was just started and waiting for user input. Some background threads are running in this situation, however they do not do any work, either. They just poll some database tables for external changes, but there were none.All of a sudden a VM would crash, leaving a hs_err_pid1234.txt behind. This is what they look like (shortened): # # An unexpected error has been detected by HotSpot Virtual Machine: # # SIGSEGV (0xb) at pc=0x402989b9, pid=8736, tid=1094691632 # # Java VM: Java HotSpot(TM) Client VM (1.5.0_09-b03 mixed mode, sharin…

Beryl on Edgy Eft

As announced previously I spent some time to get Beryl to work on my newly upgraded Edgy Eft installation. Although it did not went as smoothly as I would have hoped, it was not too troublesome either.Dual head still seems to be a major problem in many areas in Linux. This definitely something the Windows people do not have to worry about just as much, but ok, this may partly be related to the hardware vendors not providing some sort of unified and/or open drivers. Nevertheless it is now working, after some changes to my xorg.conf. Before those I always got an error message from Beryl, complaining about a missing RandR extension.The effects are really nice, some of them are however too slow for my taste in the default settings. After speeding them up a little (I do not like to wait for a context-menu to wobble into view, if it wobbles for more than a fraction of a second) I really liked it. There are some issues left, but I assume this is because of the ongoing development. E. g. wind…

Upgrade to Egdy Eft

Yesterday I read about the final release of Ubuntu 6.10, Edgy Eft. As for my good experiences with Dapper Drake I decided to upgrade. Having sort of a Debian history I was quite confident that a dist-upgrade would work quite flawlessly, especially since I had not made any deep modifications of my system (definitely a point for Ubuntu here! :)).PreparingI went to the Ubuntu homepage and read the Upgrade Notes. I had always wondered - however not really bothered to find out either - what this alternate install CD was. Now I know that it is used to save bandwidth in the upgrade process, because it can be used as a local repository source. I do however wonder, why this cannot be done with the regular install media. But anyways...UpgradingI ran the CD based upgrade as described in the upgrade notes. A graphical tool came up and asked me whether I wanted to download updates of more recent packages from the net. I said yes, suspecting that there would not be that many of them, as the whole …

Flash 9 beta in Ubuntu Dapper

Maybe I shouldn't do vacations anymore... This time I got a nasty flu two days after my return. Well, slowly I am feeling better and thought I might just tell you that the installation of the Flash Player 9 beta for Linux worked like a charm on my Ubuntu Dapper Drake (6.06) machine.I just downloaded the archive from Adobe Labs, uninstalled the previous version using apt-get and put the new libflashplayer.so file into my private plugin directory. Apart from the ds@yavin: ~$ sudo apt-get remove flashplugin-nonfree everything is described in the readme.txt file that comes included in the archive.It is really great to have synchronous audio/video playback for the first time under Linux. About time, but hey, thanks anyway :)

MySQL 5.0: DECIMALs queried with Strings

We are currently preparing a MySQL 4.1 to MySQL 5.0 migration. First tests showed a very nasty problem, however.One of our test cases incorporates queries against DECIMAL columns that use strings as the queried values. In MySQL 4.1 this works flawlessly. The reason behind this is that in contrast to 4.1 the newer server version does a (in my opinion very stupid) conversion from String to double, which in many cases cannot correctly store the precise value.This may lead to very subtle bugs, especially when using an optimistic locking approach as we do. We only noticed the problem, because we got a ConcurrentModificationException, as an update query that contained a string-ized BigDecimal did not match any rows.See MySQL bug reports 23260 and 22290 for more details.Right now this leaves us with little options but to not migrate to 4.1 as our application has several hundreds of thousands of lines where most of the database access is handled by an OR mapping layer, but there are also nume…

MySQL replication timeout trap

Today I spent several hours trying to find a problem in our application until I found out there was a problem on the MySQL side. In our setup we have several slave machines that replicate data from a master server. The slaves are configured with a series of replicate-do-table directives in the my.cnf file so that only parts of the schema get replicated. The remaining tables are modified locally, so to avoid conflicts they are not updated with data coming from the master.We do however have the need to replicate data from the master for some special-case tables. To solve this we usually have a column that indicates whether a record was created on a master or a slave machine and use an appropriate WHERE clause in all updates. This avoids collisions in concurrent INSERTs on the master and the slave. The application knows which of the two records to use.Due to historical reasons I do not want to elaborate on we did not use such a distinction column for one table (let's call it T1). Ins…

Windows: TCP Port conflicts above 1024

We have repeatedly run into problems with our JBoss application servers not being able to start after a Windows system reboot, because their configured network ports (e. g. 1099) had already been claimed by some other process.It took quite a while to find the reason, because often just trying again several times without stopping or starting any other programs, it would suddenly succeed.What turned out to be the reason is the dynamic port allocation for ports above 1024 (so called ephemeral ports). If any process requests a random port, it may get one of those you would like to use for your own applications.On Windows 2000/2003 Server installations as well as on Windows XP Pro you can reserve port ranges (even if they only cover a single port) for your applications. Effectively they are not reserved for anything specific, but just excluded from the dynamic allocation. To do so, create or edit the following registry value (type REG_MULTI_SZ/Multi-String Value): HKEY_LOCAL_MACHINE\SYSTEM…

Video colors wrong on Ubuntu

Today I was suprised to see a video in Totem with very strange colors. It almost looks as if one color component is missing. I was alredy looking for problems with Totem on the net, when I noticed that on the second screen of my dual head setup everything was fine. Moving the window half-way between the two screens gives me one half with the right and one half with wrong colors.It seems to affect different players (Xine and Mplayer, too) and all sorts of video material (tried DVD, mpg and xvid).Though I do not know for sure, I suspect the latest upgrade package that also upgraded the nvidia driver. If I do not find another solution I will try downgrading to the previous version again.

MySQL Index Analyzer: 0.04 released

Over on the MySQL Index Analyzer site I have just released version 0.04 as a downloadable package.This is the first GUI version that allows real analysis and has more features than the command line version.A quick overview of what is new:Swing GUIAnalysis features as on the command lineCopying of generated ALTER TABLE statements to the clipboardInformation on data and index size distributionRudimentary analysis of possible disk space savingsSo go have a look :)

The Register: Interesting Article on software standards

"The Register" has an interesting article called Dumb customers and dumber software standards that I recommend reading.It is about interoperability between companies and their software products and that much innovation could be gained on all sides should they aim to work closer together. A core sentence is Customers should not be deterred from participating in standards groups for fear of giving away business plans or valuable competitive information, Snow added. [...] "We have stuff we do in the financial services business - I don't speak about that stuff at places like this or in standards organizations because there's a potential loss of competitive advantage. On the other hand, we have a lot of other stuff that isn't core to our business that we'd be better served to commodify [sic]," he said..I definitely recommend having a look.

MySQL Index Analyzer: First GUI version

Over on my MySQL Index Analyzer blog I just posted two screenshots of the first working GUI drafts. If you are interested, you will have to check this version out from the SVN repository, I will prepare a new distribution package soon.

Ubuntu kernel update broke X11

Yesterday I installed an Ubuntu (Dapper Drake) kernel upgrade through the system upgrade mechanism. The new version is 2.6.15-27-686. Today, when I tried to boot, I just got a console logon, X11 refused to start because of problems with the configuration.The following log was output to /var/log/Xorg.0.log, but from what I could see, the messages were contradictory. First the NVIDIA GPU is found and several messages from the module are displayed, but at the end of the log it says Failed to load the NVIDIA kernel module!. (II) NVIDIA X Driver 1.0-8762 Mon May 15 13:09:21 PDT 2006 (II) NVIDIA Unified Driver for all Supported NVIDIA GPUs (II) Primary Device is: PCI 01:00:0 (--) Chipset NVIDIA GPU found (--) Chipset NVIDIA GPU found ... (II) Setting vga for screen 0. (II) Setting vga for screen 1. (**) NVIDIA(0): Depth 24, (--) framebuffer bpp 32 (==) NVIDIA(0): RGB weight 888 (==) NVIDIA(0): Default visual is TrueColor (==) NVIDIA(0): Using gamma correction (1.0, 1.0, 1.0) (**) NVIDIA(0…

Prevent Windows automatic updates reboot

Another one of those reminder posts: How to prevent the reboot triggered by the Windows automatic update feature.Disable automatic updates completely. Not recommended.Change the policy. Recommended.Start - Run - gpedit.mscLocal Group Policy - Computer Configuration - Administrative Templates - Windows - Components - Windows UpdatesIf you do not see the last element, use the context menu on Administrative Templates to add a new template. Pick the wuau.adm template and close the dialogs. Windows Updates should now show up.Activatge "No auto-restart for scheduled Automatic Updates Installations" and/or use a different warning interval.On XP Home go to or create the following registry key/value HKEY_LOCAL_MACHINE \Software\Policies \Microsoft\Windows \WindowsUpdate\AU\NoAutoRebootWithLoggedOnUsers (Dword) and set it to either 0 (allow reboots) or 1 (disallow reboots).

Log Buffer #9: a Carnival of the Vanities for DBAs

As did last week's Craig Mullins of dbazine.com I wrote a short post about the LogBuffer recently when I found it in my Blog's referrer list and was promptly asked if I would like to compile one myself. So here am I am, welcoming all of you to the the 9th issue of the Log Buffer, a Carnival of the Vanities for the DBA community. Once again you will find a plethora of links to all sorts of information on the one thing that keeps many of us both fed and sometimes close to blank despair. Myself being some sort of a mixture between a software developer and database admin I have had a fair amount of time over the last years to get experience especially with MySQL. I did some work with the MS SQL server, too, so I am happy to have at least one item to cover for this faction: Joseph Sack made sort of a mental note about SQL Server 2005 Instant File Initialization on his SQL Server blog. If you have been unnerved by waiting for your SQL Server to physically fill up its data files bef…

MySQL Index Analyzer 0.02 package ready for download

I just uploaded the first ready-to-use package of the MySQL Index Analyzer (version 0.02). You can download it via its download site.I recommend going to the MIA homepage to see what's new and how to use it.

Old (Bad) habits die hard

Recently I was reminded painfully of the fact that habits you have taken to once hardly ever get laid off.I usually consider myself someone who tries to write software after I have thought it through. I do not mean "over-engineering", "over-abstracting" and "over-prepare-for-anything-that-might-ever-come'ing". However I also believe that starting hacking blindly is not a good thing either. And I try to write "nice" code, even though it might be a little more work, as long as it is easier to read or just plain more stable (which is often the same).Sometimes however, especially under a tight schedule, by force of habit I (and probably any developer out there) tend to do things that upon later review make me feel deeply embarrassed. Just so I did a couple of weeks ago...I had to write a component that translates data from a legacy system, stored in plain text files, into a relational database, accessed through an object relational mapping lay…

MySQL Index Analyzer (MIA): Refactoring, Part 1

Development of a more structured version is in progress. I just committed a set of changes to the repository that changes the current, rather monolithic, single-class design to what will be the first step of a more modular one.Currently the generation of ALTER TABLE statements has been removed and the output format of the analysis is slightly different. But that is mere cosmetic.What is much more important is that now the gathering of database schema information is based on a pluggable system, designed around an interface called IndexDescriptorProvider. Up to now I have just ported the MySQL 4 stuff that was already in the first version to this new architecture. Please feel free to have a look at it and tell me what you think.Next thing I'll do is implement a provider based on the INFORMATION_SCHEMA database available in MySQL 5.x to see if I missed anything.Go to http://mysql-index-analyzer.blogspot.com for details.

MySQL Index Analyzer Basic Documentation

I posted some Basic Documentation for MySQL Index Analyzer including a simple example. This is intented to get started with the tool without having to read the code.Any ideas and suggestions for improvements are appreciated :)

Windows compressed folders... again

I wrote about the "buggyness" of the Windows Compressed Folders feature before. However today I found out an even more unbelievable bug.I copied a ZIP file containing several thousand files onto a Windows 2003 Server machine (with SP1). Once it was there I connected via RDP and right-clicked the file in the Explorer, choosing "Extract All" from the context menu.After clicking "Next" to get past the "Welcome to the Decompression Idio^H^H^H^HWizard" I chose the target directory and hit "Next" again. Immediately I was asked whether I wanted to overwrite a file already existing in the target location. As I had created a new folder to hold the archive contents I was somewhat suprised by this dialog; so I cancelled the operation and tried again.Now you won't believe it: Once the decompression starts upon clicking the second "Next" button, this very same button remains enabled and functioning! Obviously I had (by accident) click…

MySQL Index Analysis Tool

Back in January I posted a simple MySQL duplicate index finder tool. Because I read requests for such a tool on the MySQL Performance Blog I decided to open a new project on Google's code hosting service as well as a new blog to track it.So if you are interested and maybe even want to contribute to it, go have a look.

LogBuffer

Looking at the list of referrers for my 1st blog, I found one coming from Mike Kruckenberg. First of all it is a nice post to read for anyone who (has to) work with databases, so be sure you take a look.Moreover I learned about LogBuffer which I did not know before. So if anyone else dealing with databases does not know it yet, maybe you will it as interesting as I did.

Windows XP image preview broken

Today a friend called, asking if I had any idea why his Windows XP machine did not display any picture miniature in the "My Pictures" folder anymore. He had already tried to reset file type associations and some other experiments, but without any luck. Moreover using JPG files as desktop background did not work anymore.After some thinking he rembered that the problem might first have occured after installing the first WMF hotfix published by Ilfak Guilfanov even before Microsoft provided a patch.This led us to the solution. First we made sure that the patch was uninstalled by issuing the following command: msiexec.exe /X{E1CDC5B0-7AFB-11DA-8CD6-0800200C9A66}If it tells you, the program is not installed currently, you should be able to remove it from the "Add/Remove Software" control panel applet or by running "c:\Program Files\WindowMetafile\Fixunins000.exe".Finally we re-registered the Windows picture and fax viewer library by issuing this commands: reg…

From JRoller to Blogger?

This is my first entry to my freshly opened blog at blogger.com. I will try this out for a little to see if I like it more than JRoller, where I currently keep my blog. I will probably keep the two in sync for a while to get an idea of which one suits me better.

Ubuntu Framebuffer Console

Just another one of those "reminder" posts. After installing Ubuntu it booted with the splash screen in 640x480. As I can never remember the mode number for 1280x1024, here it is: kernel /boot/vmlinuz-2.6.15-25-686 root=/dev/hda1 ro quiet splash vga=794 This of course also lets you see much more text on a VT.

X11 Dual Head with nVidia

This is more a reminder for myself than a regular post. Because I have been fiddling around with the xorg.conf to get my Linux desktop right with dual head and the right resolution on each screen, I post my configuration here. If anybody finds it useful, they are welcome to copy it.I am currently using Ubuntu 6.06 (Dapper Drake) which comes with X.Org 7.0. My machine has a GeForce 5600XT based graphics board by LeadTek. It has a DVI-I and a VGA port. I installed the closed-source nvidia driver to get hardware acceleration and extended features the X.Org nv driver does not provide. Moreover I could not get dual head right with the X.Org driver.The following configuration sets up two screens, one for the left display (analogue TFT, 1280x1024) and one for the right (CRT, 1024x768). # /etc/X11/xorg.conf (xorg X Window System server configuration file) # # This file was generated by dexconf, the Debian X Configuration tool, using # values from the debconf database. # # Edit this file with …

Fedora Core 5, Part 1

Now this is the late "Part 1 of 2" (Part 2 was published first). Took me longer than expected, but I finally got it done.In the beginning there was Windows...I have been working with all versions of Windows starting with 3.0 on a 386SX16. Over the years I have gained extensive knowledge about many aspects of the inner workings, the weaknesses and strengths. Up to now I have been using Windows XP as my "main" operating system. It certainly has its flaws, but all told it is a fine piece of software.I also believe to have a somewhat profound insight into Linux. I started with Debian Potato and have since used both newer Debian versions (Woody and Sarge) as well as several flavors of Red Hat (beginning with RH9, up to FC5) and some SuSE, too. Right now I am using Ubuntu Dapper Drake 6.06 to write this. However the majority of the Linux systems I work with are servers, most of them without even running X11.While I have always liked Windows as a desktop OS I have become…

Enhanced MySQL Administrator Graphs

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Update: MySQL 4 and 5 behave differently.
In MySQL5 there is a steady activity on some handlers, probably caused by the status queries themselves. This does not happen in 4.1. I have issued a support call with MySQL and will see what to do about it.
Update 2: See the follow-up post for more information on how to work around this.MySQL Administrator is one of the graphical tools MySQL provide to manage their database servers. Apart from other things like server daemon control and a log file viewer this tool includes visual controls to display the load of the database server.Even though the out-of-the-box configuration already contains some useful diagrams, I added some new and modified the existing. If you'd like to use them, please feel free to do so, they can be downloaded here: mysqladmin_health.xml. Please notice, that this is not a java file, but I had to rename it to be able to upload it to JRoller. Just remove the ".java" from the filename.There is a file in the Ad…

MySQL 5.0, Bug 10210

In my previous post about enhancing the graphs the MySQL Administrator displays I added a remark that there seems to be a difference between MySQL 4.1 and 5.0.As it seems this has already been reported as MySQL Bug #10210 and fixed, however only for 5.1. Summarizing the bug report is easy: They implemented Heisenberg (or better: the observer effect). You cannot query the counters for e. g. the number of temporary tables created without modifiying it as you go. In 4.1 all the SHOW STATUS... commands (see the manual page) could be executed without modifying the values displayed, because they were immediately sent to the client. In 5.0 a temporary table with the result is created and then sent. This allows the use of the data in stored procedures.It is however very annoying, because it increases the noise in measuring significantly. One (somewhat clumsy) workaround is to modify the formula for the graphs you define in MySQL Administrator by subtracting the number that would otherwise be …

Fedora Core 5, Part 2

The title of this might seem a little strange as there has not been a "part one" yet, however I feel that I'd like to share this first nonetheless. Part 1 is going to be a little more exhaustive on several aspects of my searching for an alternative to Windows XP as a desktop system.This one might also be called "DVD playback on Fedora Core 5".One of the more disappointing aspects of my new Fedora Core 5 install is the apparent lack for multimedia support. Sure, there is the default totem player, but I got the impression that it tried hard to avoid playing back anything I would have liked to see or hear.Especially DVDs were a concern for me. I have bought lots of movies and TV series over the years and I surely like to watch them once in a while, if it even is only a background windows playing Star Wars (to be honest, as often as I have seen those, I would not need the picture anymore anyway ;-).I was close to revert back to Windows when I could not find any pre…

MySQL Replication: Error 1053

When setting up MySQL replication there are some things to remember. Although the setup is quite easy if you thoroughly read the documentation on MySQL's developer site you might still hit some issues.We have quite a large scale replication setup (MySQL 4.1.12) with several hundred slaves. Today we saw a very strange situation: All of the slaves stopped replicating and claimed that a statement had been partially executed on the master side. The exact message was Query partially completed on the master (error on master: 1053) and was aborted. There is a chance that your master is inconsistent at this point. If you are sure that your master is ok, run this query manually on the slave and then restart the slave with SET GLOBAL SQL_SLAVE_SKIP_COUNTER=1; START SLAVE; The error code 1053 which means as much as "server shutdown".We checked the master and could not find anything unusual. The server had not been shut down at all and nothing seemed wrong with the master replicatio…

XP activation hassles

As I wrote in my previous post I just bought a new notebook computer that came with a preinstalled Windows XP Home Edition. After I had reinstalled it, XP Home's activation would fail with a message about an invalid product key.Already suspecting something nasty going on, I searched the net for a while and found, that in April 2005 Microsoft published a Technet article titled Preserving OEM Pre-Activation when Re-installing Windows XP. From what it says Microsoft disabled the internet activation for all OEM products to prevent system builders from pre-activating their machines and selling the product keys separately.I was trying to activate at 0100h in the morning, and of course nobody was available at Microsoft. I thought that was ok, because you have 30 days to activate, but when I went to windowsupdate.com it told me that I had to activate first, because otherwise it could not run the Genuine Advantage check! Now that's to my liking! As a paying customer you have to wait ti…