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• How does fail2ban 0.9 database storage actually works?

  - by Arantir

  Fail2ban 0.9 introduce database storage to save bans on restart. But I can't find out the actual mechanism of it work. There is dbpurgeage parameter which controls lifetime of old bans, defaults to 24 hours. As I see from code research, fail2ban saves a ban to the db with timeofban equals to the moment of ban being saved. Then every dbpurgeage period it removes all bans with timeofban < MyTime.time() - self._purgeAge, in other words removes all bans have been stored more than 24 hours ago. But what if an IP was banned for the month? Does all this mean that with dbpurgeage = 86400 after restart in 24 hours I will lost all bans longer than 24 hours? I just want that all my permanent bans will be preserved in any case.

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• Several Server Errors (No database connect, can't create TCP/IP socket etc

  - by Tobias Baumeister

  My server stops taking requests on my website today. It works for some time, but then the server just stops working and throws several errors: 500 Internal Server Error Warning: mysql_connect(): Can't create TCP/IP socket (105) in [...] on line 7 Couldn't connect to database. Please try again. mysql_connect(): Host [...] is blocked because of many connection errors; unblock with 'mysqladmin flush-hosts' mod_fcgid: can't apply process slot for /var/www/cgi-bin/cgi_wrapper/cgi_wrapper (this is from Error Log) Any ideas what might cause it? operating system is Ubuntu

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• Setting up MySQL database replication [without restarting mysql]

  - by FunkyChicken

  I'm trying to setup MySQL db replication, it seems pretty straight forward. I was using this tutorial: http://www.howtoforge.com/mysql_database_replication Now I run a rather large MySQL database for a very large website, and in this tutorial it asks me to restart MySQL to apply the new settings in the /etc/my.cnf file. I'm try to avoid that step at all costs, as I know that restarting MySQL can take a few minutes on my machine (due to large logs/dbs), and I don't want any downtime. Is there a way to apply the necessary settings WITHOUT fully restarting Mysql?

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• Tool to copy errortext in "Error on page" for Microsoft Internet Explorer.

  - by user25313

  Sometimes I see an "Error on page" icon in the lower left part of Internet Explorer (e.g. version 7.0). When I click on this icon a popup-box show some error information (I do not know if the error always is an javascript error or what to be called). The popup-box can not be resized and the text cannot be copied (e.g. for use in a error report). Does anyone knows how to retrieve the information so in can be copied and used elsewhere? Maybe someone has developed a tool to do that.

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• Take all fields in a database table and put them straight into a text file

  - by DalexL

  I have an database file (mdb) file that contains a dictionary of words. A couple thousand of them. I just need the words (in the order they are already in) put into a text file. Currently they have ID's associated with them (e.g. 1, 2, 3) but I don't need it. I just need the words. What is the best way to do this? Actually, if somebody is able to find a dictionary of English words (something along the lines of a scrabble dictionary) that is free online, I'll accept that too. I just can't seem to find any good ones online.

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• Maximum execution time of 300 seconds exceeded error while importing large MySQL database

  - by Spacedust

  I'm trying to import 641 MB MySQL database with a command: mysql -u root -p ddamiane_fakty < domenyin_damian_fakty.sql but I got an error: ERROR 1064 (42000) at line 2351406: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '<br /> <b>Fatal error</b>: Maximum execution time of 300 seconds exceeded in <b' at line 253 However limits are set much higher: mysql> show global variables like "interactive_timeout"; +---------------------+-------+ | Variable_name | Value | +---------------------+-------+ | interactive_timeout | 28800 | +---------------------+-------+ 1 row in set (0.00 sec) and mysql> show global variables like "wait_timeout"; +---------------+-------+ | Variable_name | Value | +---------------+-------+ | wait_timeout | 28800 | +---------------+-------+ 1 row in set (0.00 sec)

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• Using mongodump with an auth enabled mongodb server

  - by bb-generation

  I'm trying to do a daily backup of my mongodb server (auth enabled) using the mongodump tool. mongodump provides two parameters to set the credentials: -u [ --username ] arg username -p [ --password ] arg password Unfortunately they don't provide any parameter to read the password from stdin. Therefore everytime I run this command, everyone on the server can read the password (e.g. by using ps aux). The only workaround I have found is stopping the database and directly accessing the database files using the --dbpath parameter. Is there any other solution which allows me to backup the mongodb database without stopping the server and without "publishing" my password? I am using Debian squeeze 6.0.5 amd64 with mongodb 1.4.4-3.

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• Installing Oracle11gr2 on redhat linux

  - by KItis

  I have basic question about installing applications on linux operating system. i am going to express my issue considering oracle db installation as a example. when installing oracle database , i created a user group called dba and and user in this group called ora112. so this users is allowed to install database. so my question is if ora112 uses umaks is set to 077, then no other uses will be able to configure oracle database. why do we need to follow this practice. is it a accepted procedure in application installation on Linux. please share your experience with me. thanks in advance for looking into this issue say i install java application on this way. then no other application which belongs to different user account won't be able use java running on this computer because of this access restriction.

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• Add a Graphical User Interface (GUI) to the Microsoft Robocopy Command Line Tool

  - by Lori Kaufman

  Robocopy, or “Robust File Copy,” is a command line directory replication tool from Microsoft. It is available as part of Windows 7 and Vista as a standard feature, and was available as part of the Windows Server 2003 Resource Kit. NOTE: For Windows XP, you can obtain Robocopy by downloading the resource kit. Robocopy allows you to setup simple or advanced backup strategies. It provides such features as multi-threaded copying, mirroring or synchronization mode, automatic retry, and the ability to resume the copying process. If you are comfortable with using command line tools, you can run Robocopy directly on the command line using the command syntax and options. You can also download the command line reference and usage notes for Robocopy as a PDF file. If you are more comfortable using a graphical user interface, or GUI, rather than the command line, there are a couple of options for adding a GUI to the Robocopy command line tool, making it easier to use. Both tools, RoboMirror and RichCopy, are discussed below and links to download each tool are provided. How to Factory Reset Your Android Phone or Tablet When It Won’t Boot Our Geek Trivia App for Windows 8 is Now Available Everywhere How To Boot Your Android Phone or Tablet Into Safe Mode

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• Email Alias [email protected] Replaced with New Oracle Certification Support Tool

  - by Paul Sorensen

  All Oracle Certification customer service issues previously sent to [email protected], [email protected], [email protected], or [email protected], should now be submitted as service requests via the new request tool. Support via these email aliases ends today. Managing candidate communications via this tool will enable better issue tracking capabilities and ensure that all issues are handled quickly and efficiently. The integrated tool will also help us to more easily research historical and related issues to enable improved certification communications and business processes. For now, questions related to Java, Oracle Solaris (Cluster), MySQL, NetBeans or OpenOffice.org exam or certification, will still be sent to [email protected] and resolved via email. Questions related to the status of an Oracle Certification Success Kit, will still be sent to [email protected] and resolved via email. ?We are excited about this new offering and ?c?o?n?t?i?n?u?e? ??t?o??????? ?w?o?r?k? ?t?o?w?a?r?d ?improve?d customer ?s?e?r?v?i?c?e?? for our OCP community. Thank you for your cooperation! Quick View of Oracle Certification Customer Support Oracle Certification Support: All issues that previously would have been sent to [email protected] [email protected]: All questions on Java, Oracle Solaris (Cluster), MySQL, NetBeans, OpenOffice.org exams and certifications [email protected]: All questions on the status of your Oracle Certification Success Kit

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• What is a good support knowledge base tool?

  - by Guillaume

  I have been searching for a tool to help my team organize its knowledge for resolving recurring support cases. I know this question will probably be closed, but I'll try my change anyway because I know that I can have some good answers about that. Context: our team is developing and supporting an huge applications (lots of different screens and workflow processes. We already have a good tool for managing our documentation, but we are struggling with support cases. Support action involve often quite a lot of manual steps to fix stuff and the knowledge for these actions is more 'oral transmission' than modern tools. We need an efficient way to store them in a knowledge base to be able to retrieve similar cases based on patterns (a stacktrace, an error message, a component name, a workflow step, ...) and ranked by similarity. Our wiki search is not very powerful when it come to this kind of search and the team members don't want to 'waste' time writing a report that will never be found... Do you know efficient knowledge base tool for this kind of use case ?

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• Fusion Applications Announces the Online Feature Query Tool

  - by Richard Lefebvre

  Fusion Applications Development is pleased to announce the availability of a new, online tool for viewing Fusion Features. Oracle Product Features allows you to view new features in Fusion across multiple releases, families and products. You can view online or download the data in a variety of formats, including pdf and xls. This easy-to-use tool covers the same content and therefore replaces the pdf versions of the What's New documents. You can access Oracle Product Features from the Fusion Learning Center under Featured Assets > Product Features Query Tool. It can also be found under Release Readiness > Release Overview. Oracle Product Features will be available to customers and Partners from MyOracleSupport, oracle.com and the Partner Network Fusion Learning Center in the near future.  Oracle Product Features provides you with a high level of flexibility allowing you to only see the content you want, whether it is for a single Fusion product family, such as Human Capital Management (HCM), across several releases, or to view the entire listing of new features.  Content currently incorporates all new features introduced in Releases 3, 4 and 5. Release 6 content will be added in the near future.

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• What Software or tool to ease the building of an eye catching GUI (functional) [closed]

  - by CaBieberach

  I want to make a control panel that opens different files but I'm not sure what would be the right tool/Sw to make this. In the company we have about 30 files that we use almost every day. They are all related to each other. I would like to create a "Control panel" to ease the opening and searching of these files. Kind of a control panel with 30 buttons. The only duty of this control panel is to open one of the file selected by the user. I need this "Control Panel" to: Look GREAT Open very fast Could you please recomend me some tool/Sw to acomplish this. What tool or SW is specially focused to make stunning GUIs? Note: In the company We are all using MS Windos 7. Thanks for the help! EDIT: This would be a Stand alone program installed or saved in a network drive. Each person can open the porgram and it pops the GUI. Not for the web. "Looks GREAT" is definitively a subjective matter. I want something that gives me plenty options to display/modify the objetcs that compose the GUI. So i can experiment and find what looks and works the best.

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• A Brand-new Automated Testing Tool is the Result of Telerik and ArtOfTest Merger

  Im sure youve already heard the great news about Telerik expansion and the new Telerik Automated Testing Tools division. I am excited to share what we worked on and produced for the last couple of months. New Release The latest Telerik release that went live this week added a completely new tool to Teleriks automated testing product line. The new QA Edition is tailored for QA Professionals. The QA Edition is a standalone tool that allows QAs to freely create, execute and maintain their tests without having to install Visual Studio. If you are a developer and you want something much faster and lightweight than VS, then the Standalone tool is worth trying. New IDE The QA Edition is a WPF application with interface built on top of the latest and greatest RadControls for WPF. This allowed us to configure and build intuitive and easy-to-use UI. Additionally, the rich ...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Custom Database integration with MOSS 2007

  - by Bob

  Hopefully someone has been down this road before and can offer some sound advice as far as which direction I should take. I am currently involved in a project in which we will be utilizing a custom database to store data extracted from excel files based on pre-established templates (to maintain consistency). We currently have a process (written in C#.Net 2008) that can extract the necessary data from the spreadsheets and import it into our custom database. What I am primarily interested in is figuring out the best method for integrating that process with our portal. What I would like to do is let SharePoint keep track of the metadata about the spreadsheet itself and let the custom database keep track of the data contained within the spreadsheet. So, one thing I need is a way to link spreadsheets from SharePoint to the custom database and vice versa. As these spreadsheets will be updated periodically, I need tried and true way of ensuring that the data remains synchronized between SharePoint and the custom database. I am also interested in finding out how to use the data from the custom database to create reports within the SharePoint portal. Any and all information will be greatly appreciated.

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• IList<Item> Collection Class accessing database

  - by Mike

  Hi, I have a database with Users. Users have Items. These Items can change actively. How do you access the items in a collection type format? For the user, I fill all the user properties at the time of instantiation. If I load the user's items at the time of the instantiation, and the items change, they will have old data. I was thinking, maybe I need an ItemCollection class and have that a field/property apart of the user class, that way to traverse all the user's items I could use a foreach loop. So, my question is, what is the best practice/best way of accessing the items from a database using some sort of collection? On accessing the particular Item, it needs to get the latest database information, and when the user does do a foreach loop, the latest item information must be available. I.e. What I'm trying to do Console.WriteLine(User.Items[3].ID); returns 5. //this updates the item information and saves it to the database. User.Items[3].ID = 13; //Add a new item to the database. User.Items.Add(new Item { id = 17}); foreach (Item item in User.Items) { //this would traverse all items in the database. //not some cached copy at the time of instantiation of the user. }

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• Connecting to database on web host in Visual Studio

  - by Anders Svensson

  I have a web site developed locally with a local Sql Server database. I also have a web host that provides one Sql Server database for my site. Now I want to deploy the application, and I would like to be able to manage the remote database from the Server Explorer in Visual Studio. I have the connection string used in the application, which works fine for adding, say, a datasource to a control etc. But I don't know if there's any way to use it to connect the database inside the Server Explorer so that I can add tables etc. I have read that you're supposed to be able to this instead of using the Sql Server Management Studio, but I have'nt read anything about how to connect to the remote database in it. What I have tried so far is this: I have selected Add database in Server Explorer. This brings up first a dialog where I choose Sql Server. And then I get a dialog where I can set Server name (which I tried using the ip address in the connection string below), and Authentication (where I chose Sql Server Authentication, with the user id and password from below). But when I test the connection it fails. Here's the connection string, which works fine when used for datasources in the application (obviously with different user name and password): Any help appreciated!

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• How to choose light version of database system

  - by adopilot

  I am starting one POS (Point of sale) project. Targeting system is going to be written in C# .NET 2 WinForms and as main database server We are going to use MS-SQL Server. As we have a lot of POS devices in chain for one store I will love to have backend local data base system on each POS device. Scenario are following: When main server goes down!! POS application should continue working "off-line" with local database, until connection to main server come up again. Now I am in dilemma which local database is going to be most adoptable for me. Here is some notes for helping me point me in right direction: To be Light "My POS devices art usually old and suffering with performances" To be Free "I have a lot of devices and I do not wont additional cost beside main SQL serer" One day Ill love to try all that port on Mono and Linux OS. Here is what I've researched so far: Simple XML "Light but I am afraid of performance, My main table of items is average of 10K records" SQL-Express "I am afraid that my POS devices is poor with hardware for SQLExpress, and also hard to install on each device and configure" Less known Advantage Database Server have free distribution of offline ADT system. DBF with extended Library,"Respect for good old DBFs but that era is behind Me with clipper and DBFs" MS Access Sqlite "Mostly like for now, but I am afraid how it is going to pair with MS SQL do they have same Data types". I know that in this SO is a lot of subjective data, but at least can someone recommended some others lite database system, or things that I shod most take attention before I choice database.

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• Looking for combinations of server and embedded database engines

  - by codeelegance

  I'm redesigning an application that will be run as both a single user and multiuser application. It is a .NET 2.0 application. I'm looking for server and embedded databases that work well together. I want to deploy the embedded database in the single user setup and of course, the server in the multiuser setup. Past releases have been based on MSDE but in the past year we've been having a lot of install issues: new installs hanging and leaving the system in an unknown state, upgrades disconnecting the database, etc. I migrated the application to SQL Server 2005 and the install is more reliable (as long as a user doesn't try to install over a broken MSDE installation). Since next year's release will be a complete redesign I figured now's the best time to address the database issue as well. The database has been abstracted from the rest of the application so I just need to choose which database(s) to use and write an implementation for each one. So far I've considered: SQL Server/ SQL Server Compact Edition Firebird (same DB engine is available in two different server modes and an embedded dll) Each has its own merits but I'm also interested in any other suggestions. This is a fairly simple program and its data requirements are simple as well. I don't expect it to strain whatever database I eventually choose. So easy configuration and deployment hold more weight than performance.

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• connecting to secure database from website host

  - by jim

  Hello all, I've got a requirement to both read and write data via a .net webservice to a sqlserver database that's on a private network. this database is currently accessed via a vpn connection by remote client software (on standard desktop machines) to get latest product prices and to upload product stock sales. I've been tasked with finding a way to centralise this access from a webservice that the clients then access, rather than them using the vpn route to connect directly to the database. My question is related to my .net service's relationship to the sqlserver database. What are the options for connecting to a private network vpn from a domain host in order to achive the functionality of allowing the webservice to both read and write data to the database. For now, I'm not too concerned about the client connectivity and security (tho i appreciate that this will have to be worked out too), I'm really just interested in discovering the options available in order to allow my .net webservice to connect to the private network in as painless and transparent a way as posible. The option of switching the database onto public hosting is not an option, so I have to work with the sdcenario as described above for now, unless there's a compelling rationale presented to do otherwise. thanks all... jim

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• Is it better to use a relational database or document-based database for an app like Wufoo?

  - by mboyle

  I'm working on an application that's similar to Wufoo in that it allows our users to create their own databases and collect/present records with auto generated forms and views. Since every user is creating a different schema (one user might have a database of their baseball card collection, another might have a database of their recipes) our current approach is using MySQL to create separate databases for every user with its own tables. So in other words, the databases our MySQL server contains look like: main-web-app-db (our web app containing tables for users account info, billing, etc) user_1_db (baseball_cards_table) user_2_db (recipes_table) .... And so on. If a user wants to set up a new database to keep track of their DVD collection, we'd do a "create database ..." with "create table ...". If they enter some data in and then decide they want to change a column we'd do an "alter table ....". Now, the further along I get with building this out the more it seems like MySQL is poorly suited to handling this. 1) My first concern is that switching databases every request, first to our main app's database for authentication etc, and then to the user's personal database, is going to be inefficient. 2) The second concern I have is that there's going to be a limit to the number of databases a single MySQL server can host. Pretending for a moment this application had 500,000 user databases, is MySQL designed to operate this way? What if it were a million, or more? 3) Lastly, is this method going to be a nightmare to support and scale? I've never heard of MySQL being used in this way so I do worry about how this affects things like replication and other methods of scaling. To me, it seems like MySQL wasn't built to be used in this way but what do I know. I've been looking at document-based databases like MongoDB, CouchDB, and Redis as alternatives because it seems like a schema-less approach to this particular problem makes a lot of sense. Can anyone offer some advice on this?

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• connecting to secure database on private network from website host

  - by jim

  Hello all, I've got a requirement to both read and write data via a .net webservice to a sqlserver database that's on a private network. this database is currently accessed via a vpn connection by remote client software (on standard desktop machines) to get latest product prices and to upload product stock sales. I've been tasked with finding a way to centralise this access from a webservice that the clients then access, rather than them using the vpn route to connect directly to the database. My question is related to my .net service's relationship to the sqlserver database. What are the options for connecting to a private network vpn from a domain host in order to achive the functionality of allowing the webservice to both read and write data to the database. For now, I'm not too concerned about the client connectivity and security (tho i appreciate that this will have to be worked out too), I'm really just interested in discovering the options available in order to allow my .net webservice to connect to the private network in as painless and transparent a way as posible. [edit] the webservice will also be available to the retail website in order for it to lookup product info as well as allocate stock transfers to the same sqlserver db. it will therefore be located on the same domain as the retail site The option of switching the database onto public hosting is not feasible, so I have to work with the scenario as described above for now, unless there's a compelling rationale presented to do otherwise. thanks all... jim

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• Database choices

  - by flobadob

  I have a prickly design issue regarding the choice of database technologies to use for a group of new applications. The final suite of applications would have the following database requirements... Central databases (more than one database) using mysql (myst be mysql due to justhost.com). An application to be written which accesses the multiple mysql databases on the web host. This application will also write to local serverless database (sqlite/firebird/vistadb/whatever). Different flavors of this application will be created for windows (.NET), windows mobile, android if possible, iphone if possible. So, the design task is to minimise the quantity of code to achieve this. This is going to be tricky since the languages used are already c# / java (android) and objc (iphone). Not too worried about that, but can the work required to implement the various database access layers be minimised? The serverless database will hold similar data to the mysql server, so some kind of inheritance in the DAL would be useful. Looking at hibernate/nhibernate and there is linq to whatever. So many choices!

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• Fragmented Log files could be slowing down your database

  - by Fatherjack

  Something that is sometimes forgotten by a lot of DBAs is the fact that database log files get fragmented in the same way that you get fragmentation in a data file. The cause is very different but the effect is the same – too much effort reading and writing data. Data files get fragmented as data is changed through normal system activity, INSERTs, UPDATEs and DELETEs cause fragmentation and most experienced DBAs are monitoring their indexes for fragmentation and dealing with it accordingly. However, you don’t hear about so many working on their log files. How can a log file get fragmented? I’m glad you asked. When you create a database there are at least two files created on the disk storage; an mdf for the data and an ldf for the log file (you can also have ndf files for extra data storage but that’s off topic for now). It is wholly possible to have more than one log file but in most cases there is little point in creating more than one as the log file is written to in a ‘wrap-around’ method (more on that later). When a log file is created at the time that a database is created the file is actually sub divided into a number of virtual log files (VLFs). The number and size of these VLFs depends on the size chosen for the log file. VLFs are also created in the space added to a log file when a log file growth event takes place. Do you have your log files set to auto grow? Then you have potentially been introducing many VLFs into your log file. Let’s get to see how many VLFs we have in a brand new database. USE master GO CREATE DATABASE VLF_Test ON ( NAME = VLF_Test, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test.mdf', SIZE = 100, MAXSIZE = 500, FILEGROWTH = 50 ) LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 5MB, MAXSIZE = 250MB, FILEGROWTH = 5MB ); go USE VLF_Test go DBCC LOGINFO; The results of this are firstly a new database is created with specified files sizes and the the DBCC LOGINFO results are returned to the script editor. The DBCC LOGINFO results have plenty of interesting information in them but lets first note there are 4 rows of information, this relates to the fact that 4 VLFs have been created in the log file. The values in the FileSize column are the sizes of each VLF in bytes, you will see that the last one to be created is slightly larger than the others. So, a 5MB log file has 4 VLFs of roughly 1.25 MB. Lets alter the CREATE DATABASE script to create a log file that’s a bit bigger and see what happens. Alter the code above so that the log file details are replaced by LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 1GB, MAXSIZE = 25GB, FILEGROWTH = 1GB ); With a bigger log file specified we get more VLFs What if we make it bigger again? LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 5GB, MAXSIZE = 250GB, FILEGROWTH = 5GB ); This time we see more VLFs are created within our log file. We now have our 5GB log file comprised of 16 files of 320MB each. In fact these sizes fall into all the ranges that control the VLF creation criteria – what a coincidence! The rules that are followed when a log file is created or has it’s size increased are pretty basic. If the file growth is lower than 64MB then 4 VLFs are created If the growth is between 64MB and 1GB then 8 VLFs are created If the growth is greater than 1GB then 16 VLFs are created. Now the potential for chaos comes if the default values and settings for log file growth are used. By default a database log file gets a 1MB log file with unlimited growth in steps of 10%. The database we just created is 6 MB, let’s add some data and see what happens. USE vlf_test go -- we need somewhere to put the data so, a table is in order IF OBJECT_ID('A_Table') IS NOT NULL DROP TABLE A_Table go CREATE TABLE A_Table ( Col_A int IDENTITY, Col_B CHAR(8000) ) GO -- Let's check the state of the log file -- 4 VLFs found EXECUTE ('DBCC LOGINFO'); go -- We can go ahead and insert some data and then check the state of the log file again INSERT A_Table (col_b) SELECT TOP 500 REPLICATE('a',2000) FROM sys.columns AS sc, sys.columns AS sc2 GO -- insert 500 rows and we get 22 VLFs EXECUTE ('DBCC LOGINFO'); go -- Let's insert more rows INSERT A_Table (col_b) SELECT TOP 2000 REPLICATE('a',2000) FROM sys.columns AS sc, sys.columns AS sc2 GO 10 -- insert 2000 rows, in 10 batches and we suddenly have 107 VLFs EXECUTE ('DBCC LOGINFO'); Well, that escalated quickly! Our log file is split, internally, into 107 fragments after a few thousand inserts. The same happens with any logged transactions, I just chose to illustrate this with INSERTs. Having too many VLFs can cause performance degradation at times of database start up, log backup and log restore operations so it’s well worth keeping a check on this property. How do we prevent excessive VLF creation? Creating the database with larger files and also with larger growth steps and actively choosing to grow your databases rather than leaving it to the Auto Grow event can make sure that the growths are made with a size that is optimal. How do we resolve a situation of a database with too many VLFs? This process needs to be done when the database is under little or no stress so that you don’t affect system users. The steps are: BACKUP LOG YourDBName TO YourBackupDestinationOfChoice Shrink the log file to its smallest possible size DBCC SHRINKFILE(FileNameOfTLogHere, TRUNCATEONLY) * Re-size the log file to the size you want it to, taking in to account your expected needs for the coming months or year. ALTER DATABASE YourDBName MODIFY FILE ( NAME = FileNameOfTLogHere, SIZE = TheSizeYouWantItToBeIn_MB) * – If you don’t know the file name of your log file then run sp_helpfile while you are connected to the database that you want to work on and you will get the details you need. The resize step can take quite a while This is already detailed far better than I can explain it by Kimberley Tripp in her blog 8-Steps-to-better-Transaction-Log-throughput.aspx. The result of this will be a log file with a VLF count according to the bullet list above. Knowing when VLFs are being created By complete coincidence while I have been writing this blog (it’s been quite some time from it’s inception to going live) Jonathan Kehayias from SQLSkills.com has written a great article on how to track database file growth using Event Notifications and Service Broker. I strongly recommend taking a look at it as this is going to catch any sneaky auto grows that take place and let you know about them right away. Hassle free monitoring of VLFs If you are lucky or wise enough to be using SQL Monitor or another monitoring tool that let’s you write your own custom metrics then you can keep an eye on this very easily. There is a custom metric for VLFs (written by Stuart Ainsworth) already on the site and there are some others there are very useful so take a moment or two to look around while you are there. Resources MSDN – http://msdn.microsoft.com/en-us/library/ms179355(v=sql.105).aspx Kimberly Tripp from SQLSkills.com – http://www.sqlskills.com/BLOGS/KIMBERLY/post/8-Steps-to-better-Transaction-Log-throughput.aspx Thomas LaRock at Simple-Talk.com – http://www.simple-talk.com/sql/database-administration/monitoring-sql-server-virtual-log-file-fragmentation/ Disclosure I am a Friend of Red Gate. This means that I am more than likely to say good things about Red Gate DBA and Developer tools. No matter how awesome I make them sound, take the time to compare them with other products before you contact the Red Gate sales team to make your order.

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• SQL University: Database testing and refactoring tools and examples

  - by Mladen Prajdic

  This is a post for a great idea called SQL University started by Jorge Segarra also famously known as SqlChicken on Twitter. It’s a collection of blog posts on different database related topics contributed by several smart people all over the world. So this week is mine and we’ll be talking about database testing and refactoring. In 3 posts we’ll cover: SQLU part 1 - What and why of database testing SQLU part 2 - What and why of database refactoring SQLU part 3 - Database testing and refactoring tools and examples This is the third and last part of the series and in it we’ll take a look at tools we can test and refactor with plus some an example of the both. Tools of the trade First a few thoughts about how to go about testing a database. I'm firmily against any testing tools that go into the database itself or need an extra database. Unit tests for the database and applications using the database should all be in one place using the same technology. By using database specific frameworks we fragment our tests into many places and increase test system complexity. Let’s take a look at some testing tools. 1. NUnit, xUnit, MbUnit All three are .Net testing frameworks meant to unit test .Net application. But we can test databases with them just fine. I use NUnit because I’ve always used it for work and personal projects. One day this might change. So the thing to remember is to be flexible if something better comes along. All three are quite similar and you should be able to switch between them without much problem. 2. TSQLUnit As much as this framework is helpful for the non-C# savvy folks I don’t like it for the reason I stated above. It lives in the database and thus fragments the testing infrastructure. Also it appears that it’s not being actively developed anymore. 3. DbFit I haven’t had the pleasure of trying this tool just yet but it’s on my to-do list. From what I’ve read and heard Gojko Adzic (@gojkoadzic on Twitter) has done a remarkable job with it. 4. Redgate SQL Refactor and Apex SQL Refactor Neither of these refactoring tools are free, however if you have hardcore refactoring planned they are worth while looking into. I’ve only used the Red Gate’s Refactor and was quite impressed with it. 5. Reverting the database state I’ve talked before about ways to revert a database to pre-test state after unit testing. This still holds and I haven’t changed my mind. Also make sure to read the comments as they are quite informative. I especially like the idea of setting up and tearing down the schema for each test group with NHibernate. Testing and refactoring example We’ll take a look at the simple schema and data test for a view and refactoring the SELECT * in that view. We’ll use a single table PhoneNumbers with ID and Phone columns. Then we’ll refactor the Phone column into 3 columns Prefix, Number and Suffix. Lastly we’ll remove the original Phone column. Then we’ll check how the view behaves with tests in NUnit. The comments in code explain the problem so be sure to read them. I’m assuming you know NUnit and C#. T-SQL Code C# test code USE tempdbGOCREATE TABLE PhoneNumbers( ID INT IDENTITY(1,1), Phone VARCHAR(20))GOINSERT INTO PhoneNumbers(Phone)SELECT '111 222333 444' UNION ALLSELECT '555 666777 888'GO-- notice we don't have WITH SCHEMABINDINGCREATE VIEW vPhoneNumbersAS SELECT * FROM PhoneNumbersGO-- Let's take a look at what the view returns -- If we add a new columns and rows both tests will failSELECT *FROM vPhoneNumbers GO -- DoesViewReturnCorrectColumns test will SUCCEED -- DoesViewReturnCorrectData test will SUCCEED -- refactor to split Phone column into 3 partsALTER TABLE PhoneNumbers ADD Prefix VARCHAR(3)ALTER TABLE PhoneNumbers ADD Number VARCHAR(6)ALTER TABLE PhoneNumbers ADD Suffix VARCHAR(3)GO-- update the new columnsUPDATE PhoneNumbers SET Prefix = LEFT(Phone, 3), Number = SUBSTRING(Phone, 5, 6), Suffix = RIGHT(Phone, 3)GO-- remove the old columnALTER TABLE PhoneNumbers DROP COLUMN PhoneGO-- This returns unexpected results!-- it returns 2 columns ID and Phone even though -- we don't have a Phone column anymore.-- Notice that the data is from the Prefix column-- This is a danger of SELECT *SELECT *FROM vPhoneNumbers -- DoesViewReturnCorrectColumns test will SUCCEED -- DoesViewReturnCorrectData test will FAIL -- for a fix we have to call sp_refreshview -- to refresh the view definitionEXEC sp_refreshview 'vPhoneNumbers'-- after the refresh the view returns 4 columns-- this breaks the input/output behavior of the database-- which refactoring MUST NOT doSELECT *FROM vPhoneNumbers -- DoesViewReturnCorrectColumns test will FAIL -- DoesViewReturnCorrectData test will FAIL -- to fix the input/output behavior change problem -- we have to concat the 3 columns into one named PhoneALTER VIEW vPhoneNumbersASSELECT ID, Prefix + ' ' + Number + ' ' + Suffix AS PhoneFROM PhoneNumbersGO-- now it works as expectedSELECT *FROM vPhoneNumbers -- DoesViewReturnCorrectColumns test will SUCCEED -- DoesViewReturnCorrectData test will SUCCEED -- clean upDROP VIEW vPhoneNumbersDROP TABLE PhoneNumbers [Test]public void DoesViewReturnCoorectColumns(){ // conn is a valid SqlConnection to the server's tempdb // note the SET FMTONLY ON with which we return only schema and no data using (SqlCommand cmd = new SqlCommand("SET FMTONLY ON; SELECT * FROM vPhoneNumbers", conn)) { DataTable dt = new DataTable(); dt.Load(cmd.ExecuteReader(CommandBehavior.CloseConnection)); // test returned schema: number of columns, column names and data types Assert.AreEqual(dt.Columns.Count, 2); Assert.AreEqual(dt.Columns[0].Caption, "ID"); Assert.AreEqual(dt.Columns[0].DataType, typeof(int)); Assert.AreEqual(dt.Columns[1].Caption, "Phone"); Assert.AreEqual(dt.Columns[1].DataType, typeof(string)); }} [Test]public void DoesViewReturnCorrectData(){ // conn is a valid SqlConnection to the server's tempdb using (SqlCommand cmd = new SqlCommand("SELECT * FROM vPhoneNumbers", conn)) { DataTable dt = new DataTable(); dt.Load(cmd.ExecuteReader(CommandBehavior.CloseConnection)); // test returned data: number of rows and their values Assert.AreEqual(dt.Rows.Count, 2); Assert.AreEqual(dt.Rows[0]["ID"], 1); Assert.AreEqual(dt.Rows[0]["Phone"], "111 222333 444"); Assert.AreEqual(dt.Rows[1]["ID"], 2); Assert.AreEqual(dt.Rows[1]["Phone"], "555 666777 888"); }}   With this simple example we’ve seen how a very simple schema can cause a lot of problems in the whole application/database system if it doesn’t have tests. Imagine what would happen if some outside process would depend on that view. It would get wrong data and propagate it silently throughout the system. And that is not good. So have tests at least for the crucial parts of your systems. And with that we conclude the Database Testing and Refactoring week at SQL University. Hope you learned something new and enjoy the learning weeks to come. Have fun!

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