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Open source file upload with no timeout on IIS6 with ASP, ASP.NET 2.0 or PHP5

- by Christopher Done

I'm after a cross-platform cross-browser way of uploading files such that there is no timeout. Uploads aren't necessarily huge -- some just take a long time to upload because of the uploader's slow connection -- but the server times out anyway. I hear that there are methods to upload files in chunks so that somehow the server decides not to timeout the upload. After searching around all I can see is proprietary upload helpers and Java and Flash (SWFUpload) widgets that aren't cross-platform, don't upload in chunks, or aren't free. I'd like a way to do it in any of these platforms (ASP, ASP.NET 2.0 or PHP5), though I am not very clued up on all this .NET class/controller/project/module/visual studio/compile/etc stuff, so some kind of runnable complete project that runs on .NET 2.0 would be helpful. PHP and ASP I can assume will be more straight-forward. Unless I am completely missing something, which I suspect/hope I am, reasonable web uploads are bloody hard work in any language or platform. So my question is: how can I perform web browser uploads, cross-platform, so that they don't timeout, using free software? Is it possible at all?

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Automatically release resources RAII-style in Perl

- by Philip Potter

Say I have a resource (e.g. a filehandle or network socket) which has to be freed: open my $fh, "<", "filename" or die "Couldn't open filename: $!"; process($fh); close $fh or die "Couldn't close filename: $!"; Suppose that process might die. Then the code block exits early, and $fh doesn't get closed. I could explicitly check for errors: open my $fh, "<", "filename" or die "Couldn't open filename: $!"; eval {process($fh)}; my $saved_error = $@; close $fh or die "Couldn't close filename: $!"; die $saved_error if $saved_error; but this kind of code is notoriously difficult to get right, and only gets more complicated when you add more resources. In C++ I would use RAII to create an object which owns the resource, and whose destructor would free it. That way, I don't have to remember to free the resource, and resource cleanup happens correctly as soon as the RAII object goes out of scope - even if an exception is thrown. Unfortunately in Perl a DESTROY method is unsuitable for this purpose as there are no guarantees for when it will be called. Is there a Perlish way to ensure resources are automatically freed like this even in the presence of exceptions? Or is explicit error checking the only option?

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SQL Server Table locks in long query - Solution: NoLock?

- by Kovu

a report in my application runs a query that needs between 5 - 15 seconds (constrained to count of rows that will be returned). The query has 8 joins to nearly all main-tables of my application (Customers, sales, units etc). A little tool shows me, that in this time, all those 8 tables are locked with a shared table lock. That means, no update operation will be done in this time. A solution from a friend is, to have every join in the query, which is not mandetory to have 100% correct data (dirty read), with a NoLock, so only 1 of this 8 tables will be locked completly. Is that a good solution? For a report in which 99% of data came from one table, unlock the less prio tables?

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Stop IE users typing into the file upload input

- by Dexter

My testers have discovered that if you type free text into a file upload input then none of the buttons on the page work until that text is removed (so the page cannot be submitted). I am able to replicate this with the following ASPX code (with no code behind): <%@ Page Language="C#" AutoEventWireup="true" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <body> <form id="form1" runat="server"> <div> <asp:FileUpload ID="fuTest" runat="server" /> <asp:Button ID="btnSubmit" runat="server" Text="Submit" /> </div> </form> </body> </html> (Note that I haven't bound any handlers to the page; despite this, the page is submitted when the submit button is clicked only if no text is entered into the upload text box) Is there any way to prevent users from typing free text into a file upload control? It seems that this is only possible in IE - Firefox and Chrome natively prevent text from being entered into upload input fields. I've seen solutions elsewhere which suggest hiding input and replacing it with a label / button combo, but this seems like it might cause more problems and work inconsistently across browsers. Any thoughts?

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Opening a password encrypted access database using DAO VB.NET

- by prasoon99

I create a database like this: Sub Main() Dim wrkDefault As Workspace Dim dbE As DBEngine Dim dbs As Database 'Get default Workspace. dbE = New DBEngine wrkDefault = dbE.Workspaces(0) 'Set the database filename Dim DBFilename As String DBFilename = "c:\mydb.mdb" 'Make sure there isn't already a file with the same name of 'the new database file. If Dir(DBFilename) <> "" Then MsgBox("File already exists!") Exit Sub End If 'Create a new encrypted database with the specified 'collating order. 'lock database with the password 'hello' dbs = wrkDefault.CreateDatabase(DBFilename, _ LanguageConstants.dbLangGeneral & ";pwd=hello;", DatabaseTypeEnum.dbEncrypt) dbs.Close() End Sub How do I open this database again in VB.NET using DAO?

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Should Development / Testing / QA / Staging environments be similar?

- by Walter White

Hi all, After much time and effort, we're finally using maven to manage our application lifecycle for development. We still unfortunately use ANT to build an EAR before deploying to Test / QA / Staging. My question is, while we made that leap forward, developers are still free to do as they please for testing their code. One issue that we have is half our team is using Tomcat to test on and the other half is using Jetty. I prefer Jetty slightly over Tomcat, but regardless we using WAS for all the other environments. My question is, should we develop on the same application server we're deploying to? We've had numerous bugs come up from these differences in environments. Tomcat, Jetty, and WAS are different under the hood. My opinion is that we all should develop on what we're deploying to production with so we don't have the problem of well, it worked fine on my machine. While I prefer Jetty, I just assume we all work on the same environment even if it means deploying to WAS which is slow and cumbersome. What are your team dynamics like? Our lead developers stepped down from the team and development has been a free for all since then. Walter

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NSDateFormatterFullStyle without year (NSDateFormatter)

- by Brian Halpin

Using the user's currentLocale from the device, I want to have a date format exactly like the one generated for NSDateFormatterFullStyle minus the year: [dateFormatter setDateStyle:NSDateFormatterFullStyle]; Friday, 21 September (2012) I've noticed the iPhone app, Living Earth does this and works for all locales, so does the iPhone lock screen. A custom formatter such as, [dateFormatter setDateFormat:@"EEEE, MMMM"]; won't change with localisation. Can anyone shed some light on how to accomplish this? None of the options for date style seem to do this. Thanks

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Backwards compatibility when using Core Data

- by Alex

Could anybody shed some light as to why is my app crashing with the following error on iPhone OS 2.2.1 dyld: Symbol not found: _OBJC_CLASS_$_NSPredicate Referenced from: /var/mobile/Applications/456F243F-468A-4969-9BB7-A4DF993AE89C/AppName.app/AppName Expected in: /System/Library/Frameworks/Foundation.framework/Foundation I have weak linked CoreData.framework, and have the Base SDK set to 3.0 and Deployment Target set to SDK 2.2 The app already uses other 3.0 features when available and I did not have any problems with those. But apparently the backward-compatibility methods used for other features do not work with Core Data. The app crashes before app delegate's applicationDidFinishLaunching gets called. Here's the debugger log: [Session started at 2010-05-25 20:17:03 -0400.] GNU gdb 6.3.50-20050815 (Apple version gdb-1119) (Thu May 14 05:35:37 UTC 2009) Copyright 2004 Free Software Foundation, Inc. GDB is free software, covered by the GNU General Public License, and you are welcome to change it and/or distribute copies of it under certain conditions. Type "show copying" to see the conditions. There is absolutely no warranty for GDB. Type "show warranty" for details. This GDB was configured as "--host=i386-apple-darwin --target=arm-apple-darwin".tty /dev/ttys001 Loading program into debugger… sharedlibrary apply-load-rules all warning: Unable to read symbols from "MessageUI" (not yet mapped into memory). warning: Unable to read symbols from "CoreData" (not yet mapped into memory). Program loaded. target remote-mobile /tmp/.XcodeGDBRemote-12038-42 Switching to remote-macosx protocol mem 0x1000 0x3fffffff cache mem 0x40000000 0xffffffff none mem 0x00000000 0x0fff none run Running… [Switching to thread 10755] [Switching to thread 10755] Re-enabling shared library breakpoint 1 Re-enabling shared library breakpoint 2 Re-enabling shared library breakpoint 3 Re-enabling shared library breakpoint 4 Re-enabling shared library breakpoint 5 (gdb) continue warning: Unable to read symbols for ""/Users/alex/iPhone Projects/AppName/build/Debug-iphoneos"/AppName.app/AppName" (file not found). dyld: Symbol not found: _OBJC_CLASS_$_NSPredicate Referenced from: /var/mobile/Applications/456F243F-468A-4969-9BB7-A4DF993AE89C/AppName.app/AppName Expected in: /System/Library/Frameworks/Foundation.framework/Foundation (gdb)

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SQL Server Clustered Index: (Physical) Data Page Order

- by scherand

I am struggling understanding what a clustered index in SQL Server 2005 is. I read the MSDN article Clustered Index Structures (among other things) but I am still unsure if I understand it correctly. The (main) question is: what happens if I insert a row (with a "low" key) into a table with a clustered index? The above mentioned MSDN article states: The pages in the data chain and the rows in them are ordered on the value of the clustered index key. And Using Clustered Indexes for example states: For example, if a record is added to the table that is close to the beginning of the sequentially ordered list, any records in the table after that record will need to shift to allow the record to be inserted. Does this mean that if I insert a row with a very "low" key into a table that already contains a gazillion rows literally all rows are physically shifted on disk? I cannot believe that. This would take ages, no? Or is it rather (as I suspect) that there are two scenarios depending on how "full" the first data page is. A) If the page has enough free space to accommodate the record it is placed into the existing data page and data might be (physically) reordered within that page. B) If the page does not have enough free space for the record a new data page would be created (anywhere on the disk!) and "linked" to the front of the leaf level of the B-Tree? This would then mean the "physical order" of the data is restricted to the "page level" (i.e. within a data page) but not to the pages residing on consecutive blocks on the physical hard drive. The data pages are then just linked together in the correct order. Or formulated in an alternative way: if SQL Server needs to read the first N rows of a table that has a clustered index it can read data pages sequentially (following the links) but these pages are not (necessarily) block wise in sequence on disk (so the disk head has to move "randomly"). How close am I? :)

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SQL Server Process Queue Race Condition

- by William Edmondson

I have an order queue that is accessed by multiple order processors through a stored procedure. Each processor passes in a unique ID which is used to lock the next 20 orders for its own use. The stored procedure then returns these records to the order processor to be acted upon. There are cases where multiple processors are able to retrieve the same 'OrderTable' record at which point they try to simultaneously operate on it. This ultimately results in errors being thrown later in the process. My next course of action is to allow each processor grab all available orders and just round robin the processors but I was hoping to simply make this section of code thread safe and allow the processors to grab records whenever they like. So Explicitly - Any idea why I am experiencing this race condition and how I can solve the problem. BEGIN TRAN UPDATE OrderTable WITH ( ROWLOCK ) SET ProcessorID = @PROCID WHERE OrderID IN ( SELECT TOP ( 20 ) OrderID FROM OrderTable WITH ( ROWLOCK ) WHERE ProcessorID = 0) COMMIT TRAN SELECT OrderID, ProcessorID, etc... FROM OrderTable WHERE ProcessorID = @PROCID

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How can I limit access to a particular class to one caller at a time in a web service?

- by MusiGenesis

I have a web service method in which I create a particular type of object, use it for a few seconds, and then dispose it. Because of problems arising from multiple threads creating and using instances of this class at the same time, I need to restrict the method so that only one caller at a time ever has one of these objects. To do this, I am creating a private static object: private static object _lock = new object(); ... and then inside the web service method I do this around the critical code: lock (_lock) { using (DangerousObject do = new DangerousObject()) { do.MakeABigMess(); do.CleanItUp(); } } I'm not sure this is working, though. Do I have this right? Will this code ensure that only one instance of DangerousObject is instantiated and in use at a time?

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Read assembly Guid without locking the DLL in an appdomain in medium trust ASP.Net

- by ggonsalv

Is it possible to read the GUID from the Assembly without actually loading it in the current App Domain. Normally Assembly.Load loads the DLL into the app domain. I just want to read the value. The description of the GUID is 'The following GUID is for the ID of the typelib ' if this project is exposed to COM <Assembly: Guid("DEDDE61CD-928E-4ACD-8C25-3B8577284819")> The main thing is I don't want to lock the file so that there are no errors 'Another process is accessing the file' error.

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Useful Eclipse Java Code Templates

- by Jon

You can create various Java code templates in Eclipse via the Window->Preferences->Java -> Editor -> Templates e.g. sysout is expanded to: System.out.println(${word_selection}${});${cursor} You can activate this by typing sysout followed by CTRL+SPACE What useful Java code templates do you currently use? Include the name and description of it and why it's awesome. There's an open bounty on this for an original/novel use of a template rather than a built-in existing feature. Create Log4J logger Get swt color from display Syncexec - Eclipse Framework Singleton Pattern/Enum Singleton Generation Readfile Const Traceout Format String Comment Code Review String format Try Finally Lock Message Format i18n and log Equalsbuilder Hashcodebuilder Spring Object Injection Create FileOutputStream

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video calling (center)

- by rrejc

We are starting to develop a new application and I'm searching for information/tips/guides on application architecture. Application should: read the data from an external (USB) device send the data to the remote server (through internet) receive the data from the remote server perform a video call with to the calling (support) center receive a video call call from the calling (support) center support touch screens In addition: some of the data should also be visible through the web page. So I was thinking about: On the server side: use the database (probably MS SQL) use ORM (nHibernate) to map the data from the DB to the domain objects create a layer with business logic in C# create a web (WCF) services (for client application) create an asp.net mvc application (for item 7.) to enable data view through the browser On the client side I would use WPF 4 application which will communicate with external device and the wcf services on the server. So far so good. Now the problem begins. I have no idea how to create a video call (outgoing or incoming) part of the application. I believe that there is no problem to communicate with microphone, speaker, camera with WPF/C#. But how to communicate with the call center? What protocol and encoding should be used? I think that I will need to create some kind of server which will: have a list of operators in the calling center and track which operator is occupied and which operator is free have a list of connected end users receive incoming calls from end users and delegate call to free operator delegate calls from calling center to the end user Any info, link, anything on where to start would be much appreciated. Many thanks!

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Volatile or synchronized for primitive type?

- by DKSRathore

In java, assignment is atomic if the size of the variable is less that or equal to 32 bits but is not if more than 32 bits. What(volatile/synchronized) would be more efficient to use in case of double or long assignment. like, volatile double x = y; synchronized is not applicable with primitive argument. How do i use synchronized in this case. Of course I don't want to lock my class. so this should not be used.

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Submitting R jobs using PBS

- by Tony

I am submitting a job using qsub that runs parallelized R. My intention is to have R programme running on 4 different cores rather than 8 cores. Here are some of my settings in PBS file: #PBS -l nodes=1:ppn=4 .... time R --no-save < program1.R > program1.log I am issuing the command "ta job_id" and I'm seeing that 4 cores are listed. However, the job occupies a large amount of memory(31944900k used vs 32949628k total). If I were to use 8 cores, the jobs got hang due to memory limitation. top - 21:03:53 up 77 days, 11:54, 0 users, load average: 3.99, 3.75, 3.37 Tasks: 207 total, 5 running, 202 sleeping, 0 stopped, 0 zombie Cpu(s): 30.4%us, 1.6%sy, 0.0%ni, 66.8%id, 0.0%wa, 0.0%hi, 1.2%si, 0.0%st Mem: 32949628k total, 31944900k used, 1004728k free, 269812k buffers Swap: 2097136k total, 8360k used, 2088776k free, 6030856k cached Here is a snapshot when issuing command ta job_id PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 1794 x 25 0 6247m 6.0g 1780 R 99.2 19.1 8:14.37 R 1795 x 25 0 6332m 6.1g 1780 R 99.2 19.4 8:14.37 R 1796 x 25 0 6242m 6.0g 1784 R 99.2 19.1 8:14.37 R 1797 x 25 0 6322m 6.1g 1780 R 99.2 19.4 8:14.33 R 1714 x 18 0 65932 1504 1248 S 0.0 0.0 0:00.00 bash 1761 x 18 0 63840 1244 1052 S 0.0 0.0 0:00.00 20016.hpc 1783 x 18 0 133m 7096 1128 S 0.0 0.0 0:00.00 python 1786 x 18 0 137m 46m 2688 S 0.0 0.1 0:02.06 R How can I prevent other users to use the other 4 cores? I like to mask somehow that my job is using 8 cores with 4 cores idling. Could anyone kindly help me out on this? Can this be solved using pbs? Many Thanks

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C#: Why am I still getting an RCW error when exiting my application?

- by shifuimam

To be specific, the error is: An attempt has been made to free an RCW that is in use. The RCW is in use on the active thread or another thread. Attempting to free an in-use RCW can cause corruption or data loss. The application in question is a small applet that displays the current clock speed of the CPU as a system tray icon. I'm using a System.Timers.Timer object to refresh the systray icon at an interval of 2.5 seconds. There's a single context menu item to exit the application, which uses the following function to unload everything: public void ExitApp(object sender, EventArgs e) { //stop and disable the timer theInterval.Stop(); theInterval.Enabled = false; //unload the system tray icon TheIcon.Visible = false; //exit the application Application.Exit(); } If I take out everything but Application.Exit(); I get an RCW error and the systray icon doesn't go away until I mouse over it. Everything was working perfectly until I changed the window style of the hidden form used to initialize the systray icon and the timer. If it helps any, I'm using C# 2010 Express.

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Do programmers need a union?

- by James A. Rosen

In light of the acrid responses to the intellectual property clause discussed in my previous question, I have to ask: why don't we have a programmers' union? There are many issues we face as employees, and we have very little ability to organize and negotiate. Could we band together with the writers', directors', or musicians' guilds, or are our needs unique? Has anyone ever tried to start one? If so, why did it fail? (Or, alternatively, why have I never heard of it, despite its success?) later: Keith has my idea basically right. I would also imagine the union being involved in many other topics, including: legal liability for others' use/misuse of our work, especially unintended uses evaluating the quality of computer science and software engineering higher education programs -- unlike many other engineering disciplines, we are not required to be certified on receiving our Bachelor's degrees evangelism and outreach -- especially to elementary school students certification -- not doing it, but working with the companies like ISC(2) and others to make certifications meaningful and useful continuing education -- similar to previous conferences -- maintain a go-to list of organizers and other resources our members can use I would see it less so as a traditional trade union, with little emphasis on: pay -- we tend to command fairly good salaries outsourcing and free trade -- most of use tend to be pretty free-market oriented working conditions -- we're the only industry with Aeron chairs being considered anything like "standard"

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How do I actually use Authorization Services?

- by abrahamvegh

I've been searching and experimenting for nearly four hours now, so I'm gonna just ask straight up: How can I correctly use the Authorization Services API to show the user a system-level authorization window, the same one you see when you click a lock icon in System Preferences? From what I can tell, there is no way to do it using Cocoa if you want to do it programmatically, and if your goal is to call an executable that normally needs to be called via sudo (in my case, /usr/bin/pmset) you're up a creek without a paddle. I challenge you, I implore you: Please, enlighten me. Thank you. :)

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FoxPro to C#: What best method between ODBC, OLE DB or another?

- by Martin Labelle

We need to read data from FoxPro 8 with C#. I'm gonna do some operations, and will push some of thoses data to an SQL Server database. We are not sure what's best method to read those data. I saw OLE DB and ODBC; what's best? REQUIRMENTS: The export program will run each night, but my company runs 24h a day. The DBF could sometimes be huge. We DON'T need to modify data. Our system, wich use FoxPro, is quite unstable: I need to find a way that ABSOLUTELY do not corrupt data, and, ideally, do not lock DBF files while reading. Speed is a minor requirement: it must be quick, but requirement #4 is most important.

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Setting slime-enable-evaluate-in-emacs

- by Tyler

Hi, I am using SBCL with slime, and have the following code: (swank::eval-in-emacs '(with-current-buffer (slime-repl-buffer) (insert (propertize "foo" 'font-lock-face '(:foreground "red"))))) (print "here is some text") In general if I try to execute anything with swank:: prefixed to it emacs will give a security error, and this particular one tells me I need to set slime-enable-evaluate-in-emacs to true. Where is this value? I haven't been able to find a slime or swank config. & settings file. Thanks much.

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Optimize Use of Ramdisk for Eclipse Development

- by Eric J.

We're developing Java/SpringSource applications with Eclipse on 32-bit Vista machines with 4GB RAM. The OS exposes roughly 3.3GB of RAM due to reservations for hardware etc. in the virtual address space. I came across several Ramdisk drivers that can create a virtual disk from the OS-hidden RAM and am looking for suggestions how best to use the 740MB virtual disk to speed development in our environment. The slowest part of development for us is compiling as well as launching SpringSource dm Server. One option is to configure Vista to swap to the Ramdisk. That works, and noticeably speeds up development in low memory situations. However, the 3.3GB available to the OS is often sufficient and there are many situations where we do not use the swap file(s) much. Another option is to use the Ramdisk as a location for temporary files. Using the Vista mklink command, I created a hard link from where the SpringSource dm Server's work area normally resides to the Ramdisk. That significantly improves server startup times but does nothing for compile times. There are roughly 500MB still free on the Ramdisk when the work directory is fully utilized, so room for plenty more. What other files/directories might be candidates to place on the Ramdisk? Eclipse-related files? (Parts of) the JDK? Is there a free/open source tool for Vista that will show me which files are used most frequently during a period of time to reduce the guesswork?

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How can I limit access to a particular class to one caller at a time in an ASMX web service?

- by MusiGenesis

I have a web service method in which I create a particular type of object, use it for a few seconds, and then dispose it. Because of problems arising from multiple threads creating and using instances of this class at the same time, I need to restrict the method so that only one caller at a time ever has one of these objects. To do this, I am creating a private static object: private static object _lock = new object(); ... and then inside the web service method I do this around the critical code: lock (_lock) { using (DangerousObject do = new DangerousObject()) { do.MakeABigMess(); do.CleanItUp(); } } I'm not sure this is working, though. Do I have this right? Will this code ensure that only one instance of DangerousObject is instantiated and in use at a time? Or does each caller get their own copy of _lock, rendering my code here laughable?

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Help! The log file for database 'tempdb' is full. Back up the transaction log for the database to fr

- by michael.lukatchik

We're running SQL Server 2000. In our database, we have an "Orders" table with approximately 750,000 rows. We can perform simple SELECT statements on this table. However, when we want to run a query like SELECT TOP 100 * FROM Orders ORDER BY Date_Ordered DESC, we receive the following message: Error: 9002, Severity: 17, State: 6 The log file for database 'tempdb' is full. Back up the transaction log for the database to free up some log space. We have other tables in our database which are similar in size of the amount of records that are in the tables (i.e. 700,000 records). On these tables, we can run any queries we'd like and we never receive a message about 'tempdb being full'. To resolve this, we've backed up our database, shrunk the actual database and also shrunk the database and files in the tempdb system database, but this hasn't resolved the issue. The size of our log file is set to autogrow. We're not sure where to go next. Are there any ideas why we still might be receiving this message? Error: 9002, Severity: 17, State: 6 The log file for database 'tempdb' is full. Back up the transaction log for the database to free up some log space.

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Locking NFS files in PHP

- by Oli

Part of my latest webapp needs to write to file a fair amount as part of its logging. One problem I've noticed is that if there are a few concurrent users, the writes can overwrite each other (instead of appending to file). I assume this is because of the destination file can be open in a number of places at the same time. flock(...) is usually superb but it doesn't appear to work on NFS... Which is a huge problem for me as the production server uses a NFS array. The closest thing I've seen to an actual solution involves trying to create a lock dir and waiting until it can be created. To say this lacks elegance is understatement of the year, possibly decade. Any better ideas? Edit: I should add that I don't have root on the server and doing the storage in another way isn't really feasible any time soon, not least within my deadline.

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