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  • How to transfer SQLite db to web server on android phone

    - by Shane
    Hi, I have an application that creates an SQLite database and saves information to it over the course of a day. At the end of the day i want to export this database to a web server. Could anyone point me in the right direction for this? Should I use httppost or put. I have researched this myself online but there seems to be so many different ways to explore. The server side does not exist yet either. I have access to an apache server so i am hoping to use that. Could anyone advise me the best/most simple way to do this? Thanks

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  • Windows Server 2008 and com objects

    - by Marthin
    Hi, im moving a Dll (built in c++) from windows 2000 server to a 2008 server but im have some trouble to register it. In 2000 all you normaly have to do is a "regsrv32 name.dll" but this will not work in 2008 because you get a pointer error, iv also tried to use "gacutil /i name.dll" because someone told me this might work, but it didnt. So, im kind of desperate, is there anyone that have some solution to how i can get this c++ dll to work in 2000 server so that i can access it from an old classic asp page. EDIT: This is the error when running regsrv: " The module "name.dll" was loaded but the entry-point DllRegisterServer was not found. Make sure that "name.dll" is a valid DLL or OCX file and then try again. " Note that i cant edit the dll file in anyway =( Best Regards Marthin

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  • Other users on my Server?

    - by Jennifer Weinberg
    I'm buying a Server from a person (that I don't know really well) and I want to make sure that the previous owner hasn't got any access anymore. It's an Ubuntu Virtual Server and I already received the admin access (via shell). How can I find out if there are still other accounts left, who are still able to access my server (e.g. with a still existing shell account, ftp or another type of user account)? And how can I delete them if these accounts exist? Best regards, Jennifer

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  • Server-side technology for a game

    - by Soonts
    We’re creating a massively-multiplayer social game. We expect up to 1 million concurrent users. The game is not real-time, instead it’s turn-based. We need reliable messaging between our clients and the server, preferably over HTTP protocol. Besides the multiplayer functionality, we’ll also need a content delivery service. Could you please recommend a server-side technology for us, so we’ll start searching for the right people to hire? Is it correct assumption that no single server will hold that amount of load so it must scale horizontally? Will Windows Azure do the job? Thanks in advance.

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  • [C#] Async threaded tcp server

    - by mark_dj
    I want to create a high performance server in C# which could take about ~10k clients. Now i started writing a TcpServer with C# and for each client-connection i open a new thread. I also use one thread to accept the connections. So far so good, works fine. The server has to deserialize AMF incoming objects do some logic ( like saving the position of a player ) and send some object back ( serializing objects ). I am not worried about the serializing/deserializing part atm. My main concern is that I will have a lot of threads with 10k clients and i've read somewhere that an OS can only hold like a few hunderd threads. Are there any sources/articles available on writing a decent async threaded server ? Are there other possibilties or will 10k threads work fine ? I've looked on google, but i couldn't find much info about design patterns or ways which explain it clearly

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  • ASP.NET MVC Deployed Application Server Address

    - by Jacob Huggart
    I have an application that sends an email to a user so that they may access a web form. In the email there is just a link to the start page of this form. Currently, I have the value for the form location hardcoded. Once the app is deployed I know it is in inetpub/wwwroot/appName, which results in a URL of serverip:appPort/appName. What is the C# to get the serverip:appPort portion of the URL that I need? I think that server.mappath() might work, but for some reason I can't get to the method even though I have the necessary references.

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  • Solutions for redundant server and client code?

    - by Fragsworth
    In our system, the code which exists on the client side (in Flash and Javascript) mirrors the code that exists on the server side (e.g. in Python or PHP), normally with respect to the models, the methods available for those models, and the unit tests written for them. This becomes a problem in systems where you want to minimize data transfer (e.g. multiplayer games). I do not want to write the same code and unit tests redundantly for both the client and server, but I don't know of any standard solutions to deal with this. Basically, I want a language/compiler which can produce models and methods for three main languages: Actionscript, Javascript, and any server language. Does something like this exist?

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  • What to monitor on MSSQL Server

    - by user361434
    Hi all I have been asked to monitor MSSQL Server (2005 & 2008) and am wondering what are good metrics to look at? I can access WMI counters but am slightly lost as to how much depth is going to be useful. Currently I have on my list: user connections logins per second latch waits per second total latch wait time dead locks per second errors per second Log and data file sizes I am looking to be able to monitor values that will indicate a degradation of performance on the machine or a potential serious issue. To this end I am also wondering at what values some of these things would be considered normal vs problematic? As I reckon it would probably be a really good question to have answered for the general community I thought i'd court some of you DBA experts out there (I am certainly not one of them!) Apologies if a rather open ended question. Ry

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  • Copying Some from a PostgreSQL Server to Another

    - by whollychao
    I am in need of an application that can periodically transmit select rows from a PostgreSQL database across a network to a second PostgreSQL server. Typically these will be the most recent row added, pulled and transmitted every 10-30 seconds. The primary servers run in a MS Windows environment with a high-latency, and occasionally intermittent, network connection. Therefore, any application would have to be tolerant of this and ideally automatically reconnect / resend data that could not be transmitted. Due to the environment and the requirements, a full-blown replication package would be unnecessary. I appreciate any help anyone has with this problem.

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  • Java + GWT + GSON on server side

    - by Jan
    Hi everybody. I already read that there is no possibility to run GSON in GWT client code, but that it is possible to run it in server code. The latter one is which I'm trying to achive, but not getting to work. I thought any class within the com.whatever.server package has access to the whole JRE namespace including reflection. It seems that that is not the point. So how managed all those developers to use GSON in GWT server code? (I'm new to GWT, so the answer may be really easy.) Thanks.

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  • Flex: client / server messaging question (RPC or socket ?)

    - by Patrick
    hi, I'm building a Flex application, which is going to perform many server requests (let's say, that almost all interactions require an update from server). At the moment I'm using remote procedure calls for it. But I was wondering if using a socket would be better. In other terms, is maybe better to keep the connection alive rather then performing many calls in sequence ? For my demo app I only have 1 client. Is the number of clients connecting to the server a factor for this choice ? thanks

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  • access vmware local server from internet

    - by goutham
    I have installed a ubuntu machine with apache server in Vmware-workstation Now how can I access apache server from internet using my IP. Details: network for vmware :NAT the ip address in ubuntu is 192.168.1.4 my host IP is *..239.232 if I type 192.168.1.4 in web browser I get the apache content... but if I type my host IP then I dont get it.. If I install a apache server on host(win7) I can access the host apache content with my host IP from anywhere .. I want to access the vmware apache content from internet using host IP ....

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  • Weblogic server lib VS instance libext

    - by Sebastien Lorber
    Hello, I use weblogic 10. Its provide an Oracle JDBC driver 10.2.0.2 (in the server/lib on weblogic home). Actually someone at work put a long time ago a 10.2.0.3 driver in instance libext folder. But in production we got a jdbc driver stack (nullpointer :O) and by reverse engineering it seems we are using driver 10.2.0.2. We know that we could change the driver in the server/lib of weblogic but i want to understand. Isn't libext supposed to override server libs like META-INF libs override libext? By the way we are in a strange situation: - We have 2 EAR, and for the exact same treatment in those 2, one will sometime throw the oracle driver nullpointer while the other doesn't - I wonder if one ear isn't using 10.2.0.2 while the other is using 10.2.0.3 (i saw a bug fixed that could fit to our problem for this version). - I need to look better but at first sight both ear use the exact same datasource set in weblogic JNDI resources Any idea?

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  • server side of adsense

    - by dole
    Hi there Google ask you to add a javascript code to your page and it will generate the links. The script has some id which are sent to the server, but I don't know how. <script type="text/javascript"><!-- google_ad_client = "ca-pub-1234567890123456"; /* snipet_name */ google_ad_slot = "123456789"; google_ad_width = 728; google_ad_height = 90; //--></script><script type="text/javascript" src="http://pagead2.googlesyndication.com/pagead/show_ads.js"></script> I'm curious to know how the client and slot ids are send to the server. Javascript is client side and I wish to know how those parameters are sent to the server in order to query a db and to return the links. A link, sample, explanation related to PHP will work great for me. TY

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  • Slow server response time - CakePHP

    - by Hasan
    I am using CakePHP 1.2 for building a website. The problem i am facing is when ever a page loads it takes a lot of time in "waiting for www.example.com". The server response time is very slow. First i thot it was my database queries, but they were executing in less than seconds time. Next i also contacted the server people. They told it was not the server. Now i am stuck very badly with "waiting for www.example.com". Is the problem is in coding or the cakePHP is mis configured. Need help badly and fast. Thanks

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  • Export Certificate Windows Server 2008

    - by user1432032
    I need to export the private key of a self-created SSL-certificate on a Windows Server 2008. However at Microsoft Management Console (the certificate is located, if it matter, in Personal-Certificate folder) the option "Yes, export the private key" is greyed out. Reading the provided help section it tells that the certificate needed to "be made exportable" during creation. However it also says that it is ONLY a limitation if it was created using Windows Server 2003. It doesn´t say anything how to fix it though on a Windows 2008 Server. The certificate is self-signed. I want to export to PKCS12 format. I´m accessing MMC as administrator so there should not be any permission issues. How can I make this certificate "exportable"?

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  • What approach should be suitable for user authentification in simle client/server app

    - by TerryS
    My previous question was closed so I will be more specific. I need to create an application, desktop one written in C#, that will ask for user credentials and after verification opens the GUI allowing to work with DB (black box for users). It should be used from everywhere, not LAN or SQL domain. I assume I would need to do the following: Create a client and a server applications that will deal with authentification. That would mean a lot of socketing stuff.. Once the user is verified, the client queries would be sent to database (client-server-DB). The server would need to send the DB data sets back to the client. As you can see, this is just my guess but I have no idea whether its too complicated or completely wrong. The main thing is that it must be desktop app (not web based one) and accessible from everywhere. I am interested in main points how to design the system and will be extremely grateful for that.

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  • Magento: server requirements for a quite big shop to run smoothly

    - by david parloir
    Hi, I'm working on a quite big magento: it will have 50 different shops (1 magento install, 1 admin to rule them all) for start, this number is expected to raise in the future, and a catalog of more than 1k products. This catalog will be shared by all shops. I'm concerned about the server requirements I need for this to run smoothly. So far this is what I've found to get the most of it: Caching: using magento's cache with APC, MySQL's querys Images sprite in the theme use FastCGI instead of mod_php database clustering: I don't think it will be necesary for 1k products, what do you think? using Zend Server Are there other thing I can do in order to improve magento's performance? I'd like to know all I need from the beginning so I can find the right server. thanks in advance.

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  • .net load balancing for server

    - by user1439111
    Some time ago I wrote server software which is currently running at it's max. (3k users average). So I decided to rewrite certain parts so I can run the software at another server to balance it's load. I can't simply start another instance of the server since there is some data which has to be available to all users. So I was thinking of creating a small manager and all the servers connect and send their (relevant)data to the manager. But it also got me thinking about another problem. The manager could also reach it's limits which is exactly what i'm trying to prevent in the future. So I would like to know how I could fix this problem. (I have already tried to optimize critical parts of the software but I can't optimize it forever)

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  • How to move from a physical server to an online server? [closed]

    - by Tiago
    My father has a small company: 10 PCs running Windows, 1 running Windows Server 2000 and 1 Fax/Printer. I want to remove the server and make the network based on an Online server. Can I do that? If yes, how? By using a Windows VPS? Linux VPS with VMWaRE? I'm not sure if that's a viable option, if there's other, please tell me. thank you.

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  • Management and Monitoring Tools for Windows Azure

    - by BuckWoody
    With such a large platform, Windows Azure has a lot of moving parts. We’ve done our best to keep the interface as simple as possible, while giving you the most control and visibility we can. However, as with most Microsoft products, there are multiple ways to do something – and I’ve always found that to be a good strength. Depending on the situation, I might want a graphical interface, a command-line interface, or just an API so I can incorporate the management into my own tools, or have third-party companies write other tools. While by no means exhaustive, I thought I might put together a quick list of a few tools you can use to manage and monitor Windows Azure components, from our IaaS, SaaS and PaaS offerings. Some of the products focus on one area more than another, but all are available today. I’ll try and maintain this list to keep it current, but make sure you check the date of this post’s update – if it’s more than six months old, it’s most likely out of date. Things move fast in the cloud. The Windows Azure Management Portal The primary tool for managing Windows Azure is our portal – most everything you need is there, from creating new services to querying a database. There are two versions as of this writing – a Silverlight client version, and a newer HTML5 version. The latter is being updated constantly to be in parity with the Silverlight client. There’s a balance in this portal between simplicity and power – we’re following the “less is more” approach, with increasing levels of detail as you work through the portal rather than overwhelming you with a single, long “more is more” page. You can find the Portal here: http://windowsazure.com (then click “Log In” and then “Portal”) Windows Azure Management API You can also use programming tools to either write your own interface, or simply provide management functions directly within your solution. You have two options – you can use the more universal REST API’s, which area bit more complex but work with any system that can write to them, or the more approachable .NET API calls in code. You can find the reference for the API’s here: http://msdn.microsoft.com/en-us/library/windowsazure/ee460799.aspx  All Class Libraries, for each part of Windows Azure: http://msdn.microsoft.com/en-us/library/ee393295.aspx  PowerShell Command-lets PowerShell is one of the most powerful scripting languages I’ve used with Windows – and it’s baked into all of our products. When you need to work with multiple servers, scripting is really the only way to go, and the Windows Azure PowerShell Command-Lets allow you to work across most any part of the platform – and can even be used within the services themselves. You can do everything with them from creating a new IaaS, PaaS or SaaS service, to controlling them and even working with security and more. You can find more about the Command-Lets here: http://wappowershell.codeplex.com/documentation (older link, still works, will point you to the new ones as well) We have command-line utilities for other operating systems as well: https://www.windowsazure.com/en-us/manage/downloads/  Video walkthrough of using the Command-Lets: http://channel9.msdn.com/Events/BUILD/BUILD2011/SAC-859T  System Center System Center is actually a suite of graphical tools you can use to manage, deploy, control, monitor and tune software from Microsoft and even other platforms. This will be the primary tool we’ll recommend for managing a hybrid or contiguous management process – and as time goes on you’ll see more and more features put into System Center for the entire Windows Azure suite of products. You can find the Management Pack and README for it here: http://www.microsoft.com/en-us/download/details.aspx?id=11324  SQL Server Management Studio / Data Tools / Visual Studio SQL Server has two built-in management and development, and since Version 2008 R2, you can use them to manage Windows Azure Databases. Visual Studio also lets you connect to and manage portions of Windows Azure as well as Windows Azure Databases. You can read more about Visual Studio here: http://msdn.microsoft.com/en-us/library/windowsazure/ee405484  You can read more about the SQL tools here: http://msdn.microsoft.com/en-us/library/windowsazure/ee621784.aspx  Vendor-Provided Tools Microsoft does not suggest or endorse a specific third-party product. We do, however, use them, and see lots of other customers use them. You can browse to these sites to learn more, and chat with their folks directly on how they support Windows Azure. Cerebrata: Tools for managing from the command-line, graphical diagnostics, graphical storage management - http://www.cerebrata.com/  Quest Cloud Tools: Monitoring, Storage Management, and costing tools - http://communities.quest.com/community/cloud-tools  Paraleap: Monitoring tool - http://www.paraleap.com/AzureWatch  Cloudgraphs: Monitoring too -  http://www.cloudgraphs.com/  Opstera: Monitoring for Windows Azure and a Scale-out pattern manager - http://www.opstera.com/products/Azureops/  Compuware: SaaS performance monitoring, load testing -  http://www.compuware.com/application-performance-management/gomez-apm-products.html  SOASTA: Penetration and Security Testing - http://www.soasta.com/cloudtest/enterprise/  LoadStorm: Load-testing tool - http://loadstorm.com/windows-azure  Open-Source Tools This is probably the most specific set of tools, and the list I’ll have to maintain most often. Smaller projects have a way of coming and going, so I’ll try and make sure this list is current. Windows Azure MMC: (I actually use this one a lot) http://wapmmc.codeplex.com/  Windows Azure Diagnostics Monitor: http://archive.msdn.microsoft.com/wazdmon  Azure Application Monitor: http://azuremonitor.codeplex.com/  Azure Web Log: http://www.xentrik.net/software/azure_web_log.html  Cloud Ninja:Multi-Tennant billing and performance monitor -  http://cnmb.codeplex.com/  Cloud Samurai: Multi-Tennant Management- http://cloudsamurai.codeplex.com/    If you have additions to this list, please post them as a comment and I’ll research and then add them. Thanks!

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  • Management and Monitoring Tools for Windows Azure

    - by BuckWoody
    With such a large platform, Windows Azure has a lot of moving parts. We’ve done our best to keep the interface as simple as possible, while giving you the most control and visibility we can. However, as with most Microsoft products, there are multiple ways to do something – and I’ve always found that to be a good strength. Depending on the situation, I might want a graphical interface, a command-line interface, or just an API so I can incorporate the management into my own tools, or have third-party companies write other tools. While by no means exhaustive, I thought I might put together a quick list of a few tools you can use to manage and monitor Windows Azure components, from our IaaS, SaaS and PaaS offerings. Some of the products focus on one area more than another, but all are available today. I’ll try and maintain this list to keep it current, but make sure you check the date of this post’s update – if it’s more than six months old, it’s most likely out of date. Things move fast in the cloud. The Windows Azure Management Portal The primary tool for managing Windows Azure is our portal – most everything you need is there, from creating new services to querying a database. There are two versions as of this writing – a Silverlight client version, and a newer HTML5 version. The latter is being updated constantly to be in parity with the Silverlight client. There’s a balance in this portal between simplicity and power – we’re following the “less is more” approach, with increasing levels of detail as you work through the portal rather than overwhelming you with a single, long “more is more” page. You can find the Portal here: http://windowsazure.com (then click “Log In” and then “Portal”) Windows Azure Management API You can also use programming tools to either write your own interface, or simply provide management functions directly within your solution. You have two options – you can use the more universal REST API’s, which area bit more complex but work with any system that can write to them, or the more approachable .NET API calls in code. You can find the reference for the API’s here: http://msdn.microsoft.com/en-us/library/windowsazure/ee460799.aspx  All Class Libraries, for each part of Windows Azure: http://msdn.microsoft.com/en-us/library/ee393295.aspx  PowerShell Command-lets PowerShell is one of the most powerful scripting languages I’ve used with Windows – and it’s baked into all of our products. When you need to work with multiple servers, scripting is really the only way to go, and the Windows Azure PowerShell Command-Lets allow you to work across most any part of the platform – and can even be used within the services themselves. You can do everything with them from creating a new IaaS, PaaS or SaaS service, to controlling them and even working with security and more. You can find more about the Command-Lets here: http://wappowershell.codeplex.com/documentation (older link, still works, will point you to the new ones as well) We have command-line utilities for other operating systems as well: https://www.windowsazure.com/en-us/manage/downloads/  Video walkthrough of using the Command-Lets: http://channel9.msdn.com/Events/BUILD/BUILD2011/SAC-859T  System Center System Center is actually a suite of graphical tools you can use to manage, deploy, control, monitor and tune software from Microsoft and even other platforms. This will be the primary tool we’ll recommend for managing a hybrid or contiguous management process – and as time goes on you’ll see more and more features put into System Center for the entire Windows Azure suite of products. You can find the Management Pack and README for it here: http://www.microsoft.com/en-us/download/details.aspx?id=11324  SQL Server Management Studio / Data Tools / Visual Studio SQL Server has two built-in management and development, and since Version 2008 R2, you can use them to manage Windows Azure Databases. Visual Studio also lets you connect to and manage portions of Windows Azure as well as Windows Azure Databases. You can read more about Visual Studio here: http://msdn.microsoft.com/en-us/library/windowsazure/ee405484  You can read more about the SQL tools here: http://msdn.microsoft.com/en-us/library/windowsazure/ee621784.aspx  Vendor-Provided Tools Microsoft does not suggest or endorse a specific third-party product. We do, however, use them, and see lots of other customers use them. You can browse to these sites to learn more, and chat with their folks directly on how they support Windows Azure. Cerebrata: Tools for managing from the command-line, graphical diagnostics, graphical storage management - http://www.cerebrata.com/  Quest Cloud Tools: Monitoring, Storage Management, and costing tools - http://communities.quest.com/community/cloud-tools  Paraleap: Monitoring tool - http://www.paraleap.com/AzureWatch  Cloudgraphs: Monitoring too -  http://www.cloudgraphs.com/  Opstera: Monitoring for Windows Azure and a Scale-out pattern manager - http://www.opstera.com/products/Azureops/  Compuware: SaaS performance monitoring, load testing -  http://www.compuware.com/application-performance-management/gomez-apm-products.html  SOASTA: Penetration and Security Testing - http://www.soasta.com/cloudtest/enterprise/  LoadStorm: Load-testing tool - http://loadstorm.com/windows-azure  Open-Source Tools This is probably the most specific set of tools, and the list I’ll have to maintain most often. Smaller projects have a way of coming and going, so I’ll try and make sure this list is current. Windows Azure MMC: (I actually use this one a lot) http://wapmmc.codeplex.com/  Windows Azure Diagnostics Monitor: http://archive.msdn.microsoft.com/wazdmon  Azure Application Monitor: http://azuremonitor.codeplex.com/  Azure Web Log: http://www.xentrik.net/software/azure_web_log.html  Cloud Ninja:Multi-Tennant billing and performance monitor -  http://cnmb.codeplex.com/  Cloud Samurai: Multi-Tennant Management- http://cloudsamurai.codeplex.com/    If you have additions to this list, please post them as a comment and I’ll research and then add them. Thanks!

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  • Squeezing hardware

    - by [email protected]
    It's very common that high availability means duplicate hardware so costs grows up.Nowadays, CIOs and DBAs has the main challenge of reduce the money spent increasing the performance and the availability. Since Grid Infrastructure 11gR2, there is a new feature that helps them to afford this challenge: Server PoolsNow, in Grid Infrastructure 11gR2, you can define server pools across the cluster setting up the minimum number of servers, the maximum and how important is the pool.For example:Consider  that "Velasco, Boixeda & co"  has 3 apps in a 6 servers cluster.First One is the main core business appSecond one is Mid RangeAnd third it's a database not very important.We Define the following resource requirements for expected workload:1- Main App 2 servers required2- Mid Range App requires 1 server3- Is not a required app in case of disasterThe we define 3 server pools across the cluster:1- Main pool min two servers, max three servers, importance four2- Mid pool, min one server max two servers, importance two3- test pool,min zero servers, max one server, importance oneSo the initial configuration is:-Main pool has three servers-Mid pool has two servers-Test pool has one serverLogically, we can see the cluster like this:If any server fails, the following algorithm will be applied:1.-The server pool of least importance2.-IF server pools are of the same importance,   THEN then the Server Pool that has more than its defined minimum servers Is chosenHope it helps 

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  • SQL Server Table Polling by Multiple Subscribers

    - by Daniel Hester
    Background Designing Stored Procedures that are safe for multiple subscribers (to call simultaneously) can be challenging.  For example let’s say that you want multiple worker processes to poll a shared work queue that’s encapsulated as a SQL Table. This is a common scenario and through experience you’ll find that you want to use Table Hints to prevent unwanted locking when performing simultaneous queries on the same table. There are three table hints to consider: NOLOCK, READPAST and UPDLOCK. Both NOLOCK and READPAST table hints allow you to SELECT from a table without placing a LOCK on that table. However, SELECTs with the READPAST hint will ignore any records that are locked due to being updated/inserted (or otherwise “dirty”), whereas a SELECT with NOLOCK ignores all locks including dirty reads. For the initial update of the flag (that marks the record as available for subscription) I don’t use the NOLOCK Table Hint because I want to be sensitive to the “active” records in the table and I want to exclude them.  I use an Update Lock (UPDLOCK) in conjunction with a WHERE clause that uses a sub-select with a READPAST Table Hint in order to explicitly lock the records I’m updating (UPDLOCK) but not place a lock on the table when selecting the records that I’m going to update (READPAST). UPDATES should be allowed to lock the rows affected because we’re probably changing a flag on a record so that it is not included in a SELECT from another subscriber. On the UPDATE statement we should explicitly use the UPDLOCK to guard against lock escalation. A SELECT to check for the next record(s) to process can result in a shared read lock being held by more than one subscriber polling the shared work queue (SQL table). It is expected that more than one worker process (or server) might try to process the same new record(s) at the same time. When each process then tries to obtain the update lock, none of them can because another process has a shared read lock in place. Thus without the UPDLOCK hint the result would be a lock escalation deadlock; however with the UPDLOCK hint this condition is mitigated against. Note that using the READPAST table hint requires that you also set the ISOLATION LEVEL of the transaction to be READ COMMITTED (rather than the default of SERIALIZABLE). Guidance In the Stored Procedure that returns records to the multiple subscribers: Perform the UPDATE first. Change the flag that makes the record available to subscribers.  Additionally, you may want to update a LastUpdated datetime field in order to be able to check for records that “got stuck” in an intermediate state or for other auditing purposes. In the UPDATE statement use the (UPDLOCK) Table Hint on the UPDATE statement to prevent lock escalation. In the UPDATE statement also use a WHERE Clause that uses a sub-select with a (READPAST) Table Hint to select the records that you’re going to update. In the UPDATE statement use the OUTPUT clause in conjunction with a Temporary Table to isolate the record(s) that you’ve just updated and intend to return to the subscriber. This is the fastest way to update the record(s) and to get the records’ identifiers within the same operation. Finally do a set-based SELECT on the main Table (using the Temporary Table to identify the records in the set) with either a READPAST or NOLOCK table hint.  Use NOLOCK if there are other processes (besides the multiple subscribers) that might be changing the data that you want to return to the multiple subscribers; or use READPAST if you're sure there are no other processes (besides the multiple subscribers) that might be updating column data in the table for other purposes (e.g. changes to a person’s last name).  NOLOCK is generally the better fit in this part of the scenario. See the following as an example: CREATE PROCEDURE [dbo].[usp_NewCustomersSelect] AS BEGIN -- OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON -- DECLARE TEMP TABLE -- Note that this example uses CustomerId as an identifier; -- you could just use the Identity column Id if that’s all you need. DECLARE @CustomersTempTable TABLE ( CustomerId NVARCHAR(255) ) -- PERFORM UPDATE FIRST -- [Customers] is the name of the table -- [Id] is the Identity Column on the table -- [CustomerId] is the business document key used to identify the -- record globally, i.e. in other systems or across SQL tables -- [Status] is INT or BIT field (if the status is a binary state) -- [LastUpdated] is a datetime field used to record the time of the -- last update UPDATE [Customers] WITH (UPDLOCK) SET [Status] = 1, [LastUpdated] = GETDATE() OUTPUT [INSERTED].[CustomerId] INTO @CustomersTempTable WHERE ([Id] = (SELECT TOP 100 [Id] FROM [Customers] WITH (READPAST) WHERE ([Status] = 0) ORDER BY [Id] ASC)) -- PERFORM SELECT FROM ENTITY TABLE SELECT [C].[CustomerId], [C].[FirstName], [C].[LastName], [C].[Address1], [C].[Address2], [C].[City], [C].[State], [C].[Zip], [C].[ShippingMethod], [C].[Id] FROM [Customers] AS [C] WITH (NOLOCK), @CustomersTempTable AS [TEMP] WHERE ([C].[CustomerId] = [TEMP].[CustomerId]) END In a system that has been designed to have multiple status values for records that need to be processed in the Work Queue it is necessary to have a “Watch Dog” process by which “stale” records in intermediate states (such as “In Progress”) are detected, i.e. a [Status] of 0 = New or Unprocessed; a [Status] of 1 = In Progress; a [Status] of 2 = Processed; etc.. Thus, if you have a business rule that states that the application should only process new records if all of the old records have been processed successfully (or marked as an error), then it will be necessary to build a monitoring process to detect stalled or stale records in the Work Queue, hence the use of the LastUpdated column in the example above. The Status field along with the LastUpdated field can be used as the criteria to detect stalled / stale records. It is possible to put this watchdog logic into the stored procedure above, but I would recommend making it a separate monitoring function. In writing the stored procedure that checks for stale records I would recommend using the same kind of lock semantics as suggested above. The example below looks for records that have been in the “In Progress” state ([Status] = 1) for greater than 60 seconds: CREATE PROCEDURE [dbo].[usp_NewCustomersWatchDog] AS BEGIN -- TO OVERRIDE THE DEFAULT ISOLATION LEVEL SET TRANSACTION ISOLATION LEVEL READ COMMITTED -- SET NOCOUNT ON SET NOCOUNT ON DECLARE @MaxWait int; SET @MaxWait = 60 IF EXISTS (SELECT 1 FROM [dbo].[Customers] WITH (READPAST) WHERE ([Status] = 1) AND (DATEDIFF(s, [LastUpdated], GETDATE()) > @MaxWait)) BEGIN SELECT 1 AS [IsWatchDogError] END ELSE BEGIN SELECT 0 AS [IsWatchDogError] END END Downloads The zip file below contains two SQL scripts: one to create a sample database with the above stored procedures and one to populate the sample database with 10,000 sample records.  I am very grateful to Red-Gate software for their excellent SQL Data Generator tool which enabled me to create these sample records in no time at all. References http://msdn.microsoft.com/en-us/library/ms187373.aspx http://www.techrepublic.com/article/using-nolock-and-readpast-table-hints-in-sql-server/6185492 http://geekswithblogs.net/gwiele/archive/2004/11/25/15974.aspx http://grounding.co.za/blogs/romiko/archive/2009/03/09/biztalk-sql-receive-location-deadlocks-dirty-reads-and-isolation-levels.aspx

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  • 24 Hours of PASS – first reflections

    - by Rob Farley
    A few days after the end of 24HOP, I find myself reflecting on it. I’m still waiting on most of the information. I want to be able to discover things like where the countries represented on each of the sessions, and things like that. So far, I have the feedback scores and the numbers of attendees. The data was provided in a PDF, so while I wait for it to appear in a more flexible format, I’ve pushed the 24 attendee numbers into Excel. This chart shows the numbers by time. Remember that we started at midnight GMT, which was 10:30am in my part of the world and 8pm in New York. It’s probably no surprise that numbers drooped a bit at the start, stayed comparatively low, and then grew as the larger populations of the English-speaking world woke up. I remember last time 24HOP ran for 24 hours straight, there were quite a few sessions with less than 100 attendees. None this time though. We got close, but even when it was 4am in New York, 8am in London and 7pm in Sydney (which would have to be the worst slot for attracting people), we still had over 100 people tuning in. As expected numbers grew as the UK woke up, and even more so as the US did, with numbers peaking at 755 for the “3pm in New York” session on SQL Server Data Tools. Kendra Little almost reached those numbers too, and certainly contributed the biggest ‘spike’ on the chart with her session five hours earlier. Of all the sessions, Kendra had the highest proportion of ‘Excellent’s for the “Overall Evaluation of the session” question, and those of you who saw her probably won’t be surprised by that. Kendra had one of the best ranked sessions from the 24HOP event this time last year (narrowly missing out on being top 3), and she has produced a lot of good video content since then. The reports indicate that there were nearly 8.5 thousand attendees across the 24 sessions, averaging over 350 at each one. I’m looking forward to seeing how many different people that was, although I do know that Wil Sisney managed to attend every single one (if you did too, please let me know). Wil even moderated one of the sessions, which made his feat even greater. Thanks Wil. I also want to send massive thanks to Dave Dustin. Dave probably would have attended all of the sessions, if it weren’t for a power outage that forced him to take a break. He was also a moderator, and it was during this session that he earned special praise. Part way into the session he was moderating, the speaker lost connectivity and couldn’t get back for about fifteen minutes. That’s an incredibly long time when you’re in a live presentation. There were over 200 people tuned in at the time, and I’m sure Dave was as stressed as I was to have a speaker disappear. I started chasing down a phone number for the speaker, while Dave spoke to the audience. And he did brilliantly. He started answering questions, and kept doing that until the speaker came back. Bear in mind that Dave hadn’t expected to give a presentation on that topic (or any other), and was simply drawing on his SQL expertise to get him through. Also consider that this was between midnight at 1am in Dave’s part of the world (Auckland, NZ). I would’ve been expecting just to welcome people, monitor questions, probably read some out, and in general, help make things run smoothly. He went far beyond the call of duty, and if I had a medal to give him, he’d definitely be getting one. On the whole, I think this 24HOP was a success. We tried a different platform, and I think for the most part it was a popular move. We didn’t ask the question “Was this better than LiveMeeting?”, but we did get a number of people telling us that they thought the platform was very good. Some people have told me I get a chance to put my feet up now that this is over. As I’m also co-ordinating a tour of SQLSaturday events across the Australia/New Zealand region, I don’t quite get to take that much of a break (plus, there’s the little thing of squeezing in seven SQL 2012 exams over the next 2.5 weeks). But I am pleased to be reflecting on this event rather than anticipating it. There were a number of factors that could have gone badly, but on the whole I’m pleased about how it went. A massive thanks to everyone involved. If you’re reading this and thinking you wish you could’ve tuned in more, don’t worry – they were all recorded and you’ll be able to watch them on demand very soon. But as well as that, PASS has a stream of content produced by the Virtual Chapters, so you can keep learning from the comfort of your desk all year round. More info on them at sqlpass.org, of course.

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