w i c k e d    l u s h !

I have a cron job on a web server that periodically runs mysqldump and emails me a zip file containing the database backups. I looked at one of them recently, and instead of the full DB dump, all it had in was this:

-- MySQL dump 10.11
--
-- Host: localhost    Database: dbname
-- ------------------------------------------------------
-- Server version	5.0.37-standard-log

/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8 */;
/*!40103 SET @OLD_TIME_ZONE=@@TIME_ZONE */;
/*!40103 SET TIME_ZONE='+00:00' */;
/*!40014 SET @OLD_UNIQUE_CHECKS=@@UNIQUE_CHECKS, UNIQUE_CHECKS=0 */;
/*!40014 SET @OLD_FOREIGN_KEY_CHECKS=@@FOREIGN_KEY_CHECKS,
FOREIGN_KEY_CHECKS=0 */;
/*!40101 SET @OLD_SQL_MODE=@@SQL_MODE, SQL_MODE
='NO_AUTO_VALUE_ON_ZERO' */;
/*!40111 SET @OLD_SQL_NOTES=@@SQL_NOTES, SQL_NOTES=0 */;

…and when I try running sqldump from the command line I get:

mysqldump: Got error: 1044: Access denied for user ‘usrname’@'%’ to database ‘dbname’ when using LOCK TABLES

After lots of fruitless Googling, I came across this page, which says the problem can be overcome by using the “–skip-lock-tables” flag, like this:

  mysqldump --skip-lock-tables -u usrname -p  dbname >  backup.sql

Worked perfectly!

I was using Visual Studio.NET 2005 on my Windows XP box last night (don’t flame me - I also program in Java and have several Macs), when suddenly the machine just restarted itself for no apparent reason; no blue screen, nothing - just a reboot.

When it started again, i got a pop-up dialog at the login screen. The title bar said “DfrgNtfs.exe - System Error”, and the message in the box was the unbelievably helpful “Unknown Hard Error”.

I tried looking in the system Event Log to see if I could find any clues there… - oops! I got the same “Unknown Hard Error” popup dialog - this time, with “mmc.exe - System Error” in the title bar. I tried opening a command prompt - nothing happened.

In order to try to read the crash dump file (C:WINDOWSMinidumpMini120105-01.dmp), I downloaded the microsoft free Windows debugger - WinDbg - as described in this good article:

http://www.networkworld.com/news/2005/041105-windows-crash.html?page=1

However - when I try to install it, I get another “Unknown Hard Error” popup, with “msiexec.exe” in the title bar (starting to see a pattern, here…??)

I googled, and found several people saying it could be a hardware problem - notably hard disk or ram - so I did a full disk check - no improvement. I then figured that maybe the crash was caused by some other problem, but that it must have left some system files in a corrupted state, which, in turn, caused the pop-ups.

I eventually found a discussion group where someone (unfortunately, I didn’t save the link) recommended the windows command-line command: sfc /scannow - that checks all the win system files for corruption (and possibly bribery), and repairs them from your Windows XP install disk if problems are found. I ran that from the “start menu -> run” dialog, and some of the popups stopped…, well…, popping up (notably the DfrgNtfs.exe ones), but i still got them when trying to view the event log or trying to install software.

Finally, I found the answer. The files that the System, Application and Security events are written to (the ones you view from the Event Viewer) had been corrupted - so I guess whenever I tried to do something that would create an entry in one of these logs, I got an error. The solution was found on this page:

“How to Delete Corrupt Event Viewer Log Files”
http://support.microsoft.com/?kbid=172156

…which basically says - disable the event logging service in the “Services” dialog; reboot; delete the following files from C:WINDOWSsystem32config: AppEvent.Evt, SecEvent.Evt and SysEvent.Evt (or rename them as a backup); set the event logging service back to “automatic” startup; reboot

That solved all my problems…