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  • Network architecture when using Rackspace's Cloud

    - by brianz
    I'm planning on launching a web application soon, and have decided on using Rackspace's Cloud offering with Debian. I'm not expecting that much traffic to start, but would rather get the architecture correct now even with the small VPSs. The thing I'm not quite sure about is how many VPSs I should get. At a minimum, I know I'll want three VPSs: Two Apache webservers One server for MySQL I'd also like: Nginx load balancer MySQL replication memcached I'm not sure where those last three processes should be running. Can the load balancer run on the same machine as the MySQL slave, or should they each run on their own machine? Does memcached run alongside the webservers or on different machines?

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  • Hebrew (utf8) characters in windows cmd console

    - by epeleg
    I previously asked this Q: utf8 hebrew on mysql console on debian (via putty on windows) And managed to get it working by starting mysql with --default-character-set=utf8 and setting putty to show utf8 as well. Now I need to do the same but on a windows server. The data is again the same but when I start mysql with --default-character-set=utf8 it I see multuple characters where I am supposed to see hebrew. I think the problem is with the set up of windows cmd console that it does not properly display utf8. any ideas ?

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  • How can I recover [data from] my failing USB key?

    - by moe37x3
    I have a Corsair Flash Voyager USB key, and it's almost completely failed. When I plug it into my [WinXP] computer, the OS mounts it and open up explorer to the drive's root directory. However, if I try to copy any data off, I get an error message saying that the device is not there. If I leave it plugged in, the OS seems to oscillate between seeing it and not seeing it, since the "Safely Remove Hardware" tray icon appears and disappears every few seconds. The damage was probably caused by my abuse, either from plugging it in with my keys hanging off of it or from losing the cap and keeping it in my pocket uncapped. Is there anything I can do to save the data from it or even rehabilitate the drive?

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  • Changing Word mail merge data source locations in bulk?

    - by Daft Viking
    I've just moved a number of Word mail merge files, and a number of Excel spreadsheets that are the data sources for the mail merges, from a Windows XP computer to a Windows 7 computer, and now all the paths for the merge sources are incorrect (used to be c:\documents and settings\user\my documents.... now c:\users\documents....). While I can correct the path of the data source in each file individually, I was hoping that there would be some way of updating the files in bulk, as there are a relatively large number of them. Word 2007 is what is being used, but the documents are all in the previous DOC format (not DOCX).

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  • How to configure mysqldump to avoid max_allowed_packet error

    - by Leopd
    Honestly it baffles me that with a completely default installation of mysql if I run mysqldump with default parameters it generates a SQL file that can't be imported into another completely default installation of mysql. From what I can gather it's got something to do with the max_allowed_packet setting and/or the net_buffer_length setting. I've read a bunch about this, and tried tweaking it a bunch of ways on both the export and import sides, but it still doesn't work. I keep getting the packet too big error on import. From everything I've read, here's my best guess: mysqldump --net_buffer_length=50000 myschema > giant_file.sql Because I read here that mysqldump refers to max_allowed_packet as net_buffer_length because ... uhh ... anyway. Then to import mysql --max_allowed_packet=999999 myschema < giant_file.sql But this still doesn't work. How do I export / import the database???

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  • Proftpd user-auth with mod_sql/mod_sql_passwd

    - by Zae
    I'm reading up how to interface ProFTPd with MySQL for an implementation I'm working on, I noticed it seems like all the example code or instructions I see have the user login field in MySQL set as "varchar(30)". I don't see anything saying there's a limit to the field length for ProFTPd, but I wanted to check around anyway. The project this setup is going to get mixed into was planning to have their universal usernames support "varchar(255)". Can I use that safely? or is there an FTP limitation elsewhere I'm missing? Running ProFTPd 1.3.4a(custom compiled), MySQL 5.1.54(ubuntu repos)

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  • Ganglia divide colors by rolles

    - by com
    Sorry for a silly question I am still newbie to Ganglia. In Ganglia I control few important metrics for mysql (seconds behind master and etc.). In addition I have few bunches of mysql servers (every bunch has it's own tasks, but all of the bunches should be tested for seconds behind master). I am interested if this possible to show all metrics on the one page with different colors to different bunches. Right now in metric "seconds behind master" I see all mysql servers with metric "seconds behind master" with colors to different states (red is critical, gray is ok). Can I set a color to a graph according to it's bunch? Thanks!

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  • Lingering database-connections from Feng Office

    - by Bobby
    I've installed Feng Office on our main server which is working perfectly so far. Unfortunately it seems like there's a problem with the connection to the MySQL-Database. While the connection itself works fine, it's the reuse/pooling of connections which seems to be bugged. There are lingering/sleeping connections to the server from Feng Office which won't close and don't get reused after some time (120 seconds). Of course those lingering processes/connections are piling up pretty fast. I've found a thread at the forums about this behavior, but the suggested fix is already applied (by default). I'm sure this is just a configuration issue, but I'm a little clue less because Feng is besides a MediaWiki, a DokuWiki and homebrewed PHP applications the only one with this issue. The setup is a Microsoft Windows 2003 Server with MySQL 5.0.26 and Apache 2.2. Where can I start looking for clues why this is happening and how do I get rid of lingering MySQL-Connections?

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  • Cannot Login To phpMyAdmin

    - by Zach Dziura
    I'm running a simple LAMP server at home from which I host a personal blog. The server is running Arch Linux, with the latest-and-greatest versions of Apache, MySQL, and PHP. In order to easily maintain the databases, I installed phpMyAdmin. However, I cannot login. If I were to SSH into the server and run mysql -u <user> -p <password>, no errors show up and I'm immediately placed into the MySQL prompt. No problem. However, when I try to log in with phpMyAdmin, using those exact same credentials, nothing happens. No errors, no nothing, I'm just redirected back to the login page. Did I do something wrong? Thanks in advance for any and all answers!

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  • Amazon EC2- many micro-instances vs single small/medium instance

    - by shashankaholic
    I have a chat application using stack of Openfire, Tomcat6 and MySQL. Currently, i have installed all these servers on single Linux micro-instance(613 MB memory). Even in low user base 10-20 i am encountering CPU overload which is quite obvious here. As, i am new to Amazon EC2 can somebody suggest me how to scale up my architecture according to traffic use? should i use separate micro instances for every app server(openfire,mysql,tomcat6) should i use single small or medium instance for whole server stack. Some factors in context: high reliance on MYSQL high memory usage due to file transfer web-application interacting with other Amazon service like S3,SES

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  • Amazon EC2- micro-instance vs single small/medium instance

    - by shashankaholic
    I have a chat application using stack of Openfire, Tomcat6 and MySQL. Currently, i have installed all these servers on single Linux micro-instance(613 MB memory). Even in low user base 10-20 i am encountering CPU overload which is quite obvious here. As, i am new to Amazon EC2 can somebody suggest me how to scale up my architecture according to traffic use? should i use separate micro instances for every app server(openfire,mysql,tomcat6) should i use single small or medium instance for whole server stack. Some factors in context: high reliance on MYSQL high memory usage due to file transfer web-application interacting with other Amazon service like S3,SES

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  • Unable to edit/delete/move /etc/my.cnf - Permission denied

    - by FlourishDNA
    I am trying to edit /etc/my.cnf as root user via ssh and I get following error while trying to save it I ma making changes to my.cnf as I want to tweak some values in my.cnf to meet Magento requirement like changing key_buffer_size= to higher value (128M). I assigned the value 128M to key_buffer_size= and tried to save it and then got an error. "Error writing /etc/my.cnf: Permission denied" I cant even restart MySQL successfully. [root@flourish ~]# service mysqld restart Stopping mysqld: [ OK ] MySQL Daemon failed to start. Starting mysqld: [FAILED] I can even delete or replace it with the fresh one. I tried uninstalling MySQL and re-installing but nothing worked. Permission -rw-r--r-- and Owner/Group root/root I hope there is some answer to this problem.

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  • Does replacing chrome User Data with my own - works without leaving any trace behind? Where else chrome writes data outside of User Data folder?

    - by Selin Peck
    Does replacing chrome User Data with my own - works without leaving any trace behind? Where else chrome writes data outside of User Data folder? I used to start office work by removing chrome User Data, replacing it with my own User Data copied from my external drive, saving the original User Data to other folder. Before leaving in the evening, I will take back my own User Data, and bring back the original User Data where it is originally saved. Is this process advisable? Would I be safe this way or if not, where else does chrome save data outside of User Data folder in AppData? Also, how is the process in Mozilla Firefox?

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  • Difference between key_buffers and recommendation

    - by Typeoneerror
    I'm looking to add a bit of memory to MySQL on a Linode VPS server on which I've got a small facebook (canvas app) PHP app using MySQL running. I'm not super familiar with MySQL optimization so I'm hoping to find a simple answer. I think I want to increase the key_buffer size (the default is 16M) to something like 32M to start, but I'm not sure if I need to tweak anything else as well. All I've done so far is increase the query_cache_size to 32M from 16M. There's also key_buffer under [mysqld] and key_buffer under [isamchk]. What are the difference between those two? If I have Linode 2048MB (http://www.linode.com) VPS, what would recommend I set the buffers to? I don't expect this site to have tons of visitors, but I'd like it to be as optimized as possible. Definitely way more heavy on the database access than PHP and very few HTTP requests.

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  • How do I populate multiple records of data into a PDF form like a mail-merge?

    - by user38801
    I have Acrobat Pro, and I have a PDF with a form on it. Assuming the fields in the form correspond to a data source (like rows in an RDBMS table or xml file), I want to then print multiple copies of the PDF file, with each copy having the values of a different row in the data source. It is preferable to directly interface with an actual database, rather than having to save an XML file every time I do this. If this involves programming that's cool too, I only posted here because the question didn't seem appropriate for StackOverflow. Thanks!

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  • Ways to improve completeness of files for data recovery and scanning?

    - by SteveO
    I am using R-studio for data recovery on one of my ntfs partition. There is a pdf file about 16MB, but the software can only recover 15MB of it. So I am thinking about what ways can be used to improve the quality of scanning and recovery by the software? I am looking around its preferences. I am not quite sure whether there are some adjustable parameters for scanning and recovery which can be fine-tuned to improve the quality? R-studio has a free demo version, for which scanning is free,but recovery isn't. It is downloadable from http://www.data-recovery-software.net/Data_Recovery_Download.shtml Its manual is here http://www.r-tt.com/downloads/Recovery_Manual.pdf. I have tried my best to search for answers in the manual, but failed to find one. Their technical support is not as good as their software, and helpless usually in my opinion. Thanks!

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  • my.ini optimization on Windows 2008 R2 VPS

    - by MKphpDev
    I have a vmware VPS running Windows Server 2008 R2 Enterprise that has performance issues with MySQL. Every few minutes, MySQL stall for few seconds then responed to queries. I'm sure that my.ini need to be optimized, but unfortunately, I don't have any idea of my.ini configuration. What's running on the server: 2 small wordpress blogs, 1 vbulletin forums (approx. 1.2 GB database, and increasing), small database for some sort of plug-ins (no more than 4000 records) Server Info: Processor: Intel Xeon X5550 @ 2.67GHz, RAM: 6 GB (memory useage never exceeded 2 GB), MySQL 5.5, PHP 5.3.10, IIS 7 current my.ini: [mysqld] default-storage-engine=INNODB sql-mode="STRICT_TRANS_TABLES,NO_AUTO_CREATE _USER,NO_ENGINE_SUBSTITUTION" max_connections=250 myisam_max_sort_file_size=20G innodb_additional_mem_pool_size=256M innodb_flush_log_at_trx_commit=1 innodb_log_buffer_size=8M innodb_buffer_pool_size=512MB innodb_log_file_size=128M innodb_thread_concurrency=10 key_buffer_size = 512M myisam_sort_buffer_size = 8M join_buffer_size = 256K read_buffer_size = 256K sort_buffer_size = 256K table_cache = 4000 thread_cache_size = 200 wait_timeout = 30 connect_timeout = 10 tmp_table_size = 32M max_allowed_packet = 1M max_connect_errors = 10000 query_cache_size = 16M query_cache_limit = 2M query_cache_type = 1 query_cache_min_res_unit = 1024 query_prealloc_size = 16384 query_alloc_block_size = 16384 skip-external-locking read_rnd_buffer_size=1M max_heap_table_size=16M thread_concurrency=8 [mysqld_safe] open_files_limit = 8192 [mysqldump] quick max_allowed_packet = 16M [myisamchk] key_buffer_size = 128M sort_buffer_size = 128M read_buffer = 2M write_buffer = 2M any help with that, please?

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  • Web-Server directory permissions

    - by MLS
    Hello All, I would like some help understanding web-server directory permissions. Apache, CentOS, PHP, Mysql Example, I have multiple sites in /var/www/html They are in paths like: /var/www/html/www_domainname_com inside each site I might have a path like /lib/mysql/ like PHP connect stuff, database config, etc. What should me permissions be so that someone cannot just browse to that directory? Should I just .htaccess them? I have apache:apache as the owner of all my web directories. Can I prevent someone from crawling certain directories of my web-server? I have a robots.txt, but what is to say the crawler obeys it? So to sum up: 1. What is the best owner/permission set for my sensitive files that the web-server or php or mysql needs, but I dont want people browsing to? Can I prevent straight out crawling of portions?

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  • Using Microsoft's Chart Controls In An ASP.NET Application: Serializing Chart Data

    In most usage scenarios, the data displayed in a Microsoft Chart control comes from some dynamic source, such as from a database query. The appearance of the chart can be modified dynamically, as well; past installments in this article series showed how to programmatically customize the axes, labels, and other appearance-related settings. However, it is possible to statically define the chart's data and appearance strictly through the control's declarative markup. One of the demos examined in the Getting Started article rendered a column chart with seven columns whose labels and values were defined statically in the <asp:Series> tag's <Points> collection. Given this functionality, it should come as no surprise that the Microsoft Chart Controls also support serialization. Serialization is the process of persisting the state of a control or an object to some other medium, such as to disk. Deserialization is the inverse process, and involves taking the persisted data and recreating the control or object. With just a few lines of code you can persist the appearance settings, the data, or both to a file on disk or to any stream. Likewise, it takes just a few lines of codes to reconstitute a chart from the persisted information. This article shows how to use the Microsoft Chart Control's serialization functionality by examining a demo application that allows users to create custom charts, specifying the data to plot and some appearance-related settings. The user can then save a "snapshot" of this chart, which persists its appearance and data to a record in a database. From another page, users can view these saved chart snapshots. Read on to learn more! Read More >

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  • Oracle Database Security Protecting the Oracle IRM Schema

    - by Simon Thorpe
    Acquiring the Information Rights Management technology in 2006 was part of Oracle's strategic security vision and IRM compliments nicely the overall Oracle security set of solutions. A year ago I spoke about how Oracle has solutions that can help companies protect information throughout its entire life cycle. With our acquisition of Sun this set of solutions has solidified and has even extended down to the operating system and hardware level. Oracle can now offer customers technology that protects their data from the disk, through the database to documents on the desktop! With the recent release of Oracle IRM 11g I was tasked to configure demonstration and evaluation environments and I thought it would make a nice story to leverage some of the security features in the latest release of the Oracle Database. After building these environments I thought I would put together a simple video demonstrating how both Database Advanced Security and Information Rights Management combined can provide a very secure platform for protecting your information. Have a look at the following which highlights these database security options.Transparent Data Encryption protecting the communication from the Oracle IRM server to the Database server. Encryption techniques provide confidentiality and integrity of the data passing to and from the IRM service on the back end. Transparent Data Encryption protecting the Oracle IRM database schema. Encryption is used to provide confidentiality of the IRM data whilst it resides at rest in the database table space. Database Vault is used to ensure only the Oracle IRM service has access to query and update the information that resides in the database. This is an excellent method of ensuring that database administrators cannot look at or make changes to the Oracle IRM database whilst retaining their ability to administrate the database. The last thing you want after deploying an IRM solution is for a curious or unhappy DBA to run a query that grants them rights to your company financial data or documents pertaining to a merger or acquisition.

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  • Join our webcast: Discover What’s New in Oracle Data Integrator and Oracle GoldenGate

    - by Irem Radzik
    Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:"Times New Roman","serif"; mso-fareast-font-family:"Times New Roman";} Data integration team has organized a series of webcasts for this summer. We are kicking it off this Thursday June 30th at 10am PT with a product update webcast: Discover What’s New in Oracle Data Integrator and Oracle GoldenGate. In this webcast you will hear from product management about the new patch updates to both GoldenGate 11g R1 and ODI 11gR1. Jeff Pollock, Sr. Director of Product Management for ODI will talk about the new features in Oracle Data Integrator 11.1.1.5, including the data lineage integration with OBI EE, enhanced web services to support flexible architectures as well as capabilities for efficient object execution such as Load Plans. Jeff will discuss support for complex files and performance enhancements. Chris McAllister, Sr. Director of Product Management for Oracle GoldenGate will cover the new features of Oracle GoldenGate 11.1.1.1 such as increased data security by supporting Oracle Database Advanced Security option, deeper integration with Oracle Database, and the expanded list of heterogeneous databases GoldenGate supports . Chris will also talk about the new Oracle GoldenGate 11gR1 release for HP NonStop platform and will provide information on our strategic direction for product development. Join us this Thursday at 10am PT/ 1pm ET to hear directly from Data Integration Product Management . You can register here for the June 30th webcast as well as for the upcoming ones in our summer webcast series.

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  • SQL SERVER – Concurrency Basics – Guest Post by Vinod Kumar

    - by pinaldave
    This guest post is by Vinod Kumar. Vinod Kumar has worked with SQL Server extensively since joining the industry over a decade ago. Working on various versions from SQL Server 7.0, Oracle 7.3 and other database technologies – he now works with the Microsoft Technology Center (MTC) as a Technology Architect. Let us read the blog post in Vinod’s own voice. Learning is always fun when it comes to SQL Server and learning the basics again can be more fun. I did write about Transaction Logs and recovery over my blogs and the concept of simplifying the basics is a challenge. In the real world we always see checks and queues for a process – say railway reservation, banks, customer supports etc there is a process of line and queue to facilitate everyone. Shorter the queue higher is the efficiency of system (a.k.a higher is the concurrency). Every database does implement this using checks like locking, blocking mechanisms and they implement the standards in a way to facilitate higher concurrency. In this post, let us talk about the topic of Concurrency and what are the various aspects that one needs to know about concurrency inside SQL Server. Let us learn the concepts as one-liners: Concurrency can be defined as the ability of multiple processes to access or change shared data at the same time. The greater the number of concurrent user processes that can be active without interfering with each other, the greater the concurrency of the database system. Concurrency is reduced when a process that is changing data prevents other processes from reading that data or when a process that is reading data prevents other processes from changing that data. Concurrency is also affected when multiple processes are attempting to change the same data simultaneously. Two approaches to managing concurrent data access: Optimistic Concurrency Model Pessimistic Concurrency Model Concurrency Models Pessimistic Concurrency Default behavior: acquire locks to block access to data that another process is using. Assumes that enough data modification operations are in the system that any given read operation is likely affected by a data modification made by another user (assumes conflicts will occur). Avoids conflicts by acquiring a lock on data being read so no other processes can modify that data. Also acquires locks on data being modified so no other processes can access the data for either reading or modifying. Readers block writer, writers block readers and writers. Optimistic Concurrency Assumes that there are sufficiently few conflicting data modification operations in the system that any single transaction is unlikely to modify data that another transaction is modifying. Default behavior of optimistic concurrency is to use row versioning to allow data readers to see the state of the data before the modification occurs. Older versions of the data are saved so a process reading data can see the data as it was when the process started reading and not affected by any changes being made to that data. Processes modifying the data is unaffected by processes reading the data because the reader is accessing a saved version of the data rows. Readers do not block writers and writers do not block readers, but, writers can and will block writers. Transaction Processing A transaction is the basic unit of work in SQL Server. Transaction consists of SQL commands that read and update the database but the update is not considered final until a COMMIT command is issued (at least for an explicit transaction: marked with a BEGIN TRAN and the end is marked by a COMMIT TRAN or ROLLBACK TRAN). Transactions must exhibit all the ACID properties of a transaction. ACID Properties Transaction processing must guarantee the consistency and recoverability of SQL Server databases. Ensures all transactions are performed as a single unit of work regardless of hardware or system failure. A – Atomicity C – Consistency I – Isolation D- Durability Atomicity: Each transaction is treated as all or nothing – it either commits or aborts. Consistency: ensures that a transaction won’t allow the system to arrive at an incorrect logical state – the data must always be logically correct.  Consistency is honored even in the event of a system failure. Isolation: separates concurrent transactions from the updates of other incomplete transactions. SQL Server accomplishes isolation among transactions by locking data or creating row versions. Durability: After a transaction commits, the durability property ensures that the effects of the transaction persist even if a system failure occurs. If a system failure occurs while a transaction is in progress, the transaction is completely undone, leaving no partial effects on data. Transaction Dependencies In addition to supporting all four ACID properties, a transaction might exhibit few other behaviors (known as dependency problems or consistency problems). Lost Updates: Occur when two processes read the same data and both manipulate the data, changing its value and then both try to update the original data to the new value. The second process might overwrite the first update completely. Dirty Reads: Occurs when a process reads uncommitted data. If one process has changed data but not yet committed the change, another process reading the data will read it in an inconsistent state. Non-repeatable Reads: A read is non-repeatable if a process might get different values when reading the same data in two reads within the same transaction. This can happen when another process changes the data in between the reads that the first process is doing. Phantoms: Occurs when membership in a set changes. It occurs if two SELECT operations using the same predicate in the same transaction return a different number of rows. Isolation Levels SQL Server supports 5 isolation levels that control the behavior of read operations. Read Uncommitted All behaviors except for lost updates are possible. Implemented by allowing the read operations to not take any locks, and because of this, it won’t be blocked by conflicting locks acquired by other processes. The process can read data that another process has modified but not yet committed. When using the read uncommitted isolation level and scanning an entire table, SQL Server can decide to do an allocation order scan (in page-number order) instead of a logical order scan (following page pointers). If another process doing concurrent operations changes data and move rows to a new location in the table, the allocation order scan can end up reading the same row twice. Also can happen if you have read a row before it is updated and then an update moves the row to a higher page number than your scan encounters later. Performing an allocation order scan under Read Uncommitted can cause you to miss a row completely – can happen when a row on a high page number that hasn’t been read yet is updated and moved to a lower page number that has already been read. Read Committed Two varieties of read committed isolation: optimistic and pessimistic (default). Ensures that a read never reads data that another application hasn’t committed. If another transaction is updating data and has exclusive locks on data, your transaction will have to wait for the locks to be released. Your transaction must put share locks on data that are visited, which means that data might be unavailable for others to use. A share lock doesn’t prevent others from reading but prevents them from updating. Read committed (snapshot) ensures that an operation never reads uncommitted data, but not by forcing other processes to wait. SQL Server generates a version of the changed row with its previous committed values. Data being changed is still locked but other processes can see the previous versions of the data as it was before the update operation began. Repeatable Read This is a Pessimistic isolation level. Ensures that if a transaction revisits data or a query is reissued the data doesn’t change. That is, issuing the same query twice within a transaction cannot pickup any changes to data values made by another user’s transaction because no changes can be made by other transactions. However, this does allow phantom rows to appear. Preventing non-repeatable read is a desirable safeguard but cost is that all shared locks in a transaction must be held until the completion of the transaction. Snapshot Snapshot Isolation (SI) is an optimistic isolation level. Allows for processes to read older versions of committed data if the current version is locked. Difference between snapshot and read committed has to do with how old the older versions have to be. It’s possible to have two transactions executing simultaneously that give us a result that is not possible in any serial execution. Serializable This is the strongest of the pessimistic isolation level. Adds to repeatable read isolation level by ensuring that if a query is reissued rows were not added in the interim, i.e, phantoms do not appear. Preventing phantoms is another desirable safeguard, but cost of this extra safeguard is similar to that of repeatable read – all shared locks in a transaction must be held until the transaction completes. In addition serializable isolation level requires that you lock data that has been read but also data that doesn’t exist. Ex: if a SELECT returned no rows, you want it to return no. rows when the query is reissued. This is implemented in SQL Server by a special kind of lock called the key-range lock. Key-range locks require that there be an index on the column that defines the range of values. If there is no index on the column, serializable isolation requires a table lock. Gets its name from the fact that running multiple serializable transactions at the same time is equivalent of running them one at a time. Now that we understand the basics of what concurrency is, the subsequent blog posts will try to bring out the basics around locking, blocking, deadlocks because they are the fundamental blocks that make concurrency possible. Now if you are with me – let us continue learning for SQL Server Locking Basics. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology Tagged: Concurrency

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  • Announcing Sesame Data Browser

    - by Fabrice Marguerie
    At the occasion of MIX10, which is currently taking place in Las Vegas, I'd like to announce Sesame Data Browser.Sesame will be a suite of tools for dealing with data, and Sesame Data Browser will be the first tool from that suite.Today, during the second MIX10 keynote, Microsoft demonstrated how they are pushing hard to get OData adopted. If you don't know about OData, you can visit the just revamped dedicated website: http://odata.org. There you'll find about the OData protocol, which allows you to publish and consume data on the web, the OData SDK (with client libraries for .NET, Java, Javascript, PHP, iPhone, and more), a list of OData producers, and a list of OData consumers.This is where Sesame Data Browser comes into play. It's one of the tools you can use today to consume OData.I'll let you have a look, but be aware that this is just a preview and many additional features are coming soon.Sesame Data Browser is part of a bigger picture than just OData that will take shape over the coming months. Sesame is a project I've been working on for many months now, so what you see now is just a start :-)I hope you'll enjoy what you see. Let me know what you think.

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  • Methodology behind fetching large XML data sets in pieces

    - by Jerry Dodge
    I am working on an HTTP Server in Delphi which simply sends back a custom XML dataset. I am not following any type of standard formatting, such as SOAP. I have the system working seamlessly, except one small flaw: When I have a very large dataset to send back to the client, it might take up to 2 minutes for all the data to be transferred. The HTTP Server I'm building is essentially an XML Data based API around a database, implementing the common business rule - therefore, the requests are specific to the data behind the system. When, for example, I fetch a large set of product data, I would like to break this down and send it back piece by piece. However, a single HTTP request calls for a single response. I can't necessarily keep feeding the client with multiple different XML packets unless the client explicitly requests it. I don't have any session management, but rather an API Key. I know if I had sessions, I could keep-alive a dataset temporarily for a client, and they could request bits and pieces of it. However, without session management, I would have to execute the SQL query multiple times (for each chunk of data), and in the mean-time, if that data changes, the "pages" might get messed up, therefore causing items to show on the wrong pages, after navigating to a different page. So how is this commonly handled? What's the methodology behind breaking down a large XML dataset into chunks to save the load?

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