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• need assistance with my.cnf - 1500% CPU usage

  - by Alan Long

  I'm running into a few issues with our new database server. It is a HP G8 with 2 INTEL XEON E5-2650 processors and 32GB of ram. This server is dedicated as a MySQL server (5.1.69) for our intranet portal. I have been having issues with this server staying alive - I notice high CPU usage during certain times of day (8% ~ 1500%+) and see very low memory usage (7 ~ 15%) based on using the 'top' command. When the CPU usage passes 1000%, that is when the app usually dies. I'm trying to see what I'm doing wrong with the config file, hopefully one of the experts can chime in and let me know what they think. See below for my.cnf file: [mysqld] default-storage-engine=InnoDB datadir=/var/lib/mysql socket=/var/lib/mysql/mysql.sock #user=mysql large-pages # Disabling symbolic-links is recommended to prevent assorted security risks symbolic-links=0 max_connections=275 tmp_table_size=1G key_buffer_size=384M key_buffer=384M thread_cache_size=1024 long_query_time=5 low_priority_updates=1 max_heap_table_size=1G myisam_sort_buffer_size=8M concurrent_insert=2 table_cache=1024 sort_buffer_size=8M read_buffer_size=5M read_rnd_buffer_size=6M join_buffer_size=16M table_definition_cache=6k open_files_limit=8k slow_query_log #skip-name-resolve # Innodb Settings innodb_buffer_pool_size=18G innodb_thread_concurrency=0 innodb_log_file_size=1G innodb_log_buffer_size=16M innodb_flush_log_at_trx_commit=2 innodb_lock_wait_timeout=50 innodb_file_per_table #innodb_buffer_pool_instances=4 #eliminating double buffering innodb_flush_method = O_DIRECT flush_time=86400 innodb_additional_mem_pool_size=40M #innodb_io_capacity = 5000 #innodb_read_io_threads = 64 #innodb_write_io_threads = 64 # increase until threads_created doesnt grow anymore thread_cache=1024 query_cache_type=1 query_cache_limit=4M query_cache_size=256M # Try number of CPU's*2 for thread_concurrency thread_concurrency = 0 wait_timeout = 1800 connect_timeout = 10 interactive_timeout = 60 [mysqldump] max_allowed_packet=32M [mysqld_safe] log-error=/var/log/mysqld.log pid-file=/var/run/mysqld/mysqld.pid log-slow-queries=/var/log/mysql/slow-queries.log long_query_time = 1 log-queries-not-using-indexes we connect to one database with 75 tables, the largest table has 1,150,000 entries and the second largest has 128,036 entries. I have also verified that our PHP queries are optimized as best as possible. Reference - MySQLtuner: >> MySQLTuner 1.2.0 - Major Hayden <[email protected]> >> Bug reports, feature requests, and downloads at http://mysqltuner.com/ >> Run with '--help' for additional options and output filtering -------- General Statistics -------------------------------------------------- [--] Skipped version check for MySQLTuner script [OK] Currently running supported MySQL version 5.1.69-log [OK] Operating on 64-bit architecture -------- Storage Engine Statistics ------------------------------------------- [--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster [--] Data in InnoDB tables: 420M (Tables: 75) [!!] Total fragmented tables: 75 -------- Security Recommendations ------------------------------------------- [!!] User '[email protected]' has no password set. -------- Performance Metrics ------------------------------------------------- [--] Up for: 1h 14m 50s (8M q [1K qps], 705 conn, TX: 6B, RX: 892M) [--] Reads / Writes: 68% / 32% [--] Total buffers: 19.7G global + 35.2M per thread (275 max threads) [!!] Maximum possible memory usage: 29.1G (93% of installed RAM) [OK] Slow queries: 0% (472/8M) [OK] Highest usage of available connections: 66% (183/275) [OK] Key buffer size / total MyISAM indexes: 384.0M/91.0K [OK] Key buffer hit rate: 100.0% (173 cached / 0 reads) [OK] Query cache efficiency: 96.2% (7M cached / 7M selects) [!!] Query cache prunes per day: 553614 [OK] Sorts requiring temporary tables: 0% (3 temp sorts / 1K sorts) [!!] Temporary tables created on disk: 49% (3K on disk / 7K total) [OK] Thread cache hit rate: 74% (183 created / 705 connections) [OK] Table cache hit rate: 97% (231 open / 238 opened) [OK] Open file limit used: 0% (17/8K) [OK] Table locks acquired immediately: 100% (432K immediate / 432K locks) [OK] InnoDB data size / buffer pool: 420.9M/18.0G -------- Recommendations ----------------------------------------------------- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance MySQL started within last 24 hours - recommendations may be inaccurate Reduce your overall MySQL memory footprint for system stability Increasing the query_cache size over 128M may reduce performance Temporary table size is already large - reduce result set size Reduce your SELECT DISTINCT queries without LIMIT clauses Variables to adjust: *** MySQL's maximum memory usage is dangerously high *** *** Add RAM before increasing MySQL buffer variables *** query_cache_size (> 256M) [see warning above] Thanks in advanced for your help!

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• Writing Macros to find a specific cell and paste the value from a control cell into it

  - by G-Edinburgh

  I am having some issues writing a Macro to do the following. I have a very long list of rooms with two columns one containing the room number i.e. B-CL102 and the other containing a varying integer.I am looking to create a new column that will contain another different integer for each of the rooms. Is there any way to write a Macro so that I can use two control cells at the top of the sheet, type the room number into one and the integer matching that room into another, then run the Macro and it will automatically populate the correct cell. Then I can change the two values in the control cells and run the Macro again and so on. Thanks for your help, I have a very minimal amount of experience with Macros essentially just the basics. Thanks G

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• Need help understanding Mocks and Stubs

  - by Theomax

  I'm new to use mocking frameworks and I have a few questions on the things that I am not clear on. I'm using Rhinomocks to generate mock objects in my unit tests. I understand that mocks can be created to verify interactions between methods and they record the interactions etc and stubs allow you to setup data and entities required by the test but you do not verify expectations on stubs. Looking at the recent unit tests I have created, I appear to be creating mocks literally for the purpose of stubbing and allowing for data to be setup. Is this a correct usage of mocks or is it incorrect if you're not actually calling verify on them? For example: user = MockRepository.GenerateMock<User>(); user.Stub(x => x.Id = Guid.NewGuid()); user.Stub(x => x.Name = "User1"); In the above code I generate a new user mock object, but I use a mock so I can stub the properties of the user because in some cases if the properties do not have a setter and I need to set them it seems the only way is to stub the property values. Is this a correct usage of stubbing and mocking? Also, I am not completely clear on what the difference between the following lines is: user.Stub(x => x.Id).Return(new Guid()); user.Stub(x => x.Id = Guid.NewGuid());

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• Boundary conditions for testing

  - by Loggie

  Ok so in a programming test I was given the following question. Question 1 (1 mark) Spot the potential bug in this section of code: void Class::Update( float dt ) { totalTime += dt; if( totalTime == 3.0f ) { // Do state change m_State++; } } The multiple choice answers for this question were. a) It has a constant floating point number where it should have a named constant variable b) It may not change state with only an equality test c) You don't know what state you are changing to d) The class is named poorly I wrongly answered this with answer C. I eventually received feedback on the answers and the feedback for this question was Correct answer is a. This is about understanding correct boundary conditions for tests. The other answers are arguably valid points, but do not indicate a potential bug in the code. My question here is, what does this have to do with boundary conditions? My understanding of boundary conditions is checking that a value is within a certain range, which isn't the case here. Upon looking over the question, in my opinion, B should be the correct answer when considering the accuracy issues of using floating point values.

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• Changing the Default Install Location of an MSI

  - by PSteele

  A few months ago, I had to tweak an MSI installer.  It was installing into a specific directory (named the same as the application) underneath Program Files.  Since the location of Program Files can change from machine to machine, the MSI has a special token you can use for Program Files (as well as for the application name).  So the current value for “DefaultLocation” of the Application Folder was: [ProgramFilesFolder]\[ProductName] During installation, these tokens would be replaced by the actual location based on the current machine. I needed to change this to a specific folder underneath the users My Documents directory.  I poked around the help file and I could not find where these special tokens (like “[ProgramFilesFolder]”) were defined.  Obviously, there must be some specific set of values that are available and I’m sure My Documents is one of them. I finally found them documented so I’m posting the link here.  Hopefully, it will help someone else out.  Not sure where I found this link… System Folder Properties For me, it was as easy as changing the DefaultLocation to: [PersonalFolder]\MyToolName\Application Technorati Tags: .NET,MSI

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• When decomposing a large function, how can I avoid the complexity from the extra subfunctions?

  - by missingno

  Say I have a large function like the following: function do_lots_of_stuff(){ { //subpart 1 ... } ... { //subpart N ... } } a common pattern is to decompose it into subfunctions function do_lots_of_stuff(){ subpart_1(...) subpart_2(...) ... subpart_N(...) } I usually find that decomposition has two main advantages: The decomposed function becomes much smaller. This can help people read it without getting lost in the details. Parameters have to be explicitly passed to the underlying subfunctions, instead of being implicitly available by just being in scope. This can help readability and modularity in some situations. However, I also find that decomposition has some disadvantages: There are no guarantees that the subfunctions "belong" to do_lots_of_stuff so there is nothing stopping someone from accidentally calling them from a wrong place. A module's complexity grows quadratically with the number of functions we add to it. (There are more possible ways for things to call each other) Therefore: Are there useful convention or coding styles that help me balance the pros and cons of function decomposition or should I just use an editor with code folding and call it a day? EDIT: This problem also applies to functional code (although in a less pressing manner). For example, in a functional setting we would have the subparts be returning values that are combined in the end and the decomposition problem of having lots of subfunctions being able to use each other is still present. We can't always assume that the problem domain will be able to be modeled on just some small simple types with just a few highly orthogonal functions. There will always be complicated algorithms or long lists of business rules that we still want to correctly be able to deal with. function do_lots_of_stuff(){ p1 = subpart_1() p2 = subpart_2() pN = subpart_N() return assembleStuff(p1, p2, ..., pN) }

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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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• Iozone: sensible settings for a server with lots of RAM

  - by Frank Brenner

  I have just acquired a server with: 2x quadcore Xeons 48G ECC RAM 5x 160GB SSDs on an LSI 9260-8i Before deploying the target platform, I'd like to collect as much benchmark data as possible, testing I/O with hardware RAID in various configurations, ZFS zRAID, as well as I/O performance on vSphere and with KVM virtualization. In order to see real disk I/O performance without cache effects, I tried running Iozone with a maximum file of more than twice the physical RAM as recommended in the documentation, so: iozone -a -g100G However, as one might expect, this takes far too long to be practicable. (I stopped the run after seven hours..) I'd like to reduce the range of record and file sizes to values that might reflect realistic performance for an application server, hopefully getting the run times to under an hour or so. Any ideas? Thanks.

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• Cocos-2D asteroids style movement (iOS)

  - by bwheeler96

  So I have a CCSprite subclass, well call this Spaceship. Spaceship needs to move on a loop, until I say othersise by calling a method. The method should look something like - (void)moveForeverAtVelocity { // method logic } The class Spaceship has two relevant iVars, resetPosition and targetPosition, the target is where we are headed, the reset is where we set to when we've hit our target. If they are both off-screen this creates a permanent looping effect. So for the logic, I have tried several things, such as CCMoveTo *move = [CCMoveTo actionWithDuration:2 position:ccp(100, 100)]; CCCallBlockN *repeat = [CCCallBlockN actionWithBlock: ^(CCNode *node) { [self moveForeverAtVelocity]; }]; [self runAction:[CCSequence actions: move, repeat, nil]]; self.position = self.resetPosition; recursively calling the moveForeverAtVelocity method. This is psuedo-code, so its not perfect. I have hard-coded some of the values for the sake of simplicity. Enough garble: The problem I am having, how can I make a method that loops forever, but can be called and reset at will. I'm running into issues with creating multiple instances of this method. If you can offer any assistance with creating this effect, that would be appreciated.

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• check two conditions in two different columns in excel and count the matches

  - by user1727103

  I've trying to create a Error Log to help me analyse my mistakes. So for simplicity, lets assume I have two columns "Type of Question" - with values SC,RC,CR and another column that indicates whether I got this question "right/wrong".Let's assume this is my table: Question No. | Right/Wrong | Question Type | Right | SC | Right | RC | Wrong | SC | Wrong | CR | Right | RC (Pardon my formatting skills). And I want an output table like this Type of Question | Right | Wrong | Total SC | 1 | 1 | 2 RC | 2 | 0 | 2 CR | 0 | 1 | 1 So basically what I want to do is check Column3 for SC using =COUNTIF(C1:C5,"SC"), and return the total number of SC questions, and then outta the SC , I need to find out which are Right.If I know the right and the total I can get the wrong. I have never written a macro so a formula based answer would suffice.

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• JavaScript and the User Experience

  5 sites I commonly vist at home: Google.com Gmail.com Linkedin.com Capella.edu Codeplex.com All of the top 5 sites I visit at home use JavaScript and is applied in various ways for various reasons. Gmail and Google make use of Ajax to retrieve information without the user having to call another page. In addition, all 5 of the websites use JavaScript to enhance a user's experience. Examples of this can be found in content rotation on Capella's main site and the displaying and hiding of specific content sections from within our course room. Codeplex uses Ajax and JavaScript to show dynamic content on its homepage and allow users to page through the data. I think there use of JavaScript is well placed and enhances the viewing experience of the user because it reduces the amount of interaction a user has to perform for them to obtain information they are looking to see. I have used JavaScript in various ways. One of the most memorable ways was to enable an HTML table to be able to have its rows paged and sorted based on the values in each table row.  

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• Matlab: Why is '1' + 1 == 50? [migrated]

  - by phi

  Matlab has weak dynamic typing, which is what causes this weird behaviour. What I do not understand is what exactly happens, as this result really surprises me. Edit: To clarify, what I'm describing is clearly a result of Matlab storing chars in ASCII-format, which was also mentioned in the comments. I'm more interested in the way Matlab handles its variables, and specifically, how and when it assigns a type/tag to the values. Thanks. '1' is a 1-by-1 matrix of chars in matlab and '123' is a 1-by-3 matrix of chars. As expected, 1 returns a 1-by-1 double. Now if I enter '1' + 1 I get 50 as a 1-by-1 double, and if I enter '123' + 1 I get a 1-by-3 double [ 50 51 52 ] Furthermore, if I type 'a' + 1 the result is 98 in a 1-by-1 double. I assume this has to do with how Matlab stores char-variables in ascii form, but how exactly is it handling these? Are the data actually unityped and tagged, or how does it work? Thanks.

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• Quick Fix for GlassFish/MySQL NoPasswordCredential Found

  - by MarkH

  Just the other day, I stood up a GlassFish 3.1.2 server in preparation for a new web app we've developed. Since we're using MySQL as the back-end database, I configured it for MySQL (driver) and created the requisite JDBC resource and supporting connection pool. Pinging the finished pool returned a success, and all was well. Until we fired up the app, that is -- in this case, after a weekend. Funny how things seem to break when you leave them alone for a couple of days. :-) Strangely, the error indicated "No PasswordCredential found". Time to re-check that pool. All the usual properties and values were there (URL, driverClass, serverName, databaseName, portNumber, user, password) and were populated correctly. Yes, the password field, too. And it had pinged successfully. So why the problem? A bit of searching online produced enough relevant material to offer promise. I didn't take notes as I was investigating the cause (note to self), but here were the general steps I took to resolve the issue: First, per some guidance I had found, I tried resetting the password value to nothing (using () for a value). Of course, this didn't fix anything; the database account requires a password. And when I tried to put the value back, GlassFish politely refused. Hmm. I'd seen that some folks created a new pool to replace the "broken" one, and while that did work for them, it seemed to simply side-step the issue. So I deleted the password property - which GlassFish allowed me to do - and restarted the domain. Once I was back in, I re-added the password property and its value, saved it, and pinged...success! But now to the app for the litmus test. The web app worked, and everything and everyone was now happy. Not bad for a Monday.  :-D Hope this helps, Mark

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• How to modify partitions after install?

  - by ChocoDeveloper

  I wanted to have Ubuntu with full disk encryption on one big partition, and Windows on a small one. In 12.04, only the Server Edition installer has full disk encryption, so I used that and then installed ubuntu-desktop. When it asked for the size, I reduced it from ~999GB to ~750gb. Now after the install, on both gparted and disk utility I see /dev/sda2 taking ~931GB, and nothing unallocated, so I can't create a partition for windows. I got the size right, because when I right-click inside a folder, then hit 'properties', I see Free space: ~690GB (I don't know why it's not ~750GB, but at least it's not 900). The command df -h shows the same. So what can I do? Normally I would just resize a partition with gparted to create unallocated space, then create the partition. But here I have two problems: gparted does not seem to be showing the correct values, and also it says it does not support LUKS so I'm afraid it will mess things up. Any thoughts?

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• Getting Center and Radius of Irregural Object

  - by Moaz ELdeen

  I have drawn an asteroid object manually , and would like to get its center/radius by a specific equation. I think I can get them by calculated and hard-coded values. The code to draw the asteroid: void Asteroid::Draw() { float ratio = app::getWindowWidth()/app::getWindowHeight(); gl::pushMatrices(); gl::translate(m_Pos*ratio); gl::scale(3.5*ratio,3.5*ratio,3.5*ratio); gl::color(ci::Color(1,1,1)); gl::drawLine(Vec2f(-15,0),Vec2f(-10,-5)); gl::drawLine(Vec2f(-10,-5),Vec2f(-5,-5)); gl::drawLine(Vec2f(-5,-5),Vec2f(-5,-8)); gl::drawLine(Vec2f(-5,-8),Vec2f(5,-8)); gl::drawLine(Vec2f(5,-8),Vec2f(5,-5)); gl::drawLine(Vec2f(5,-5),Vec2f(10,-5)); gl::drawLine(Vec2f(10,-5),Vec2f(15,0)); gl::drawLine(Vec2f(15,0),Vec2f(10,5)); gl::drawLine(Vec2f(10,5),Vec2f(-10,5)); gl::drawLine(Vec2f(-10,5),Vec2f(-10,5)); gl::drawLine(Vec2f(-15,0),Vec2f(-10,5)); gl::popMatrices(); } According to the answer I have written that code to calculate the radius, is it correct or not ? cinder::Vec2f Asteroid::getCenter() { return ci::Vec2f(m_Pos.x, m_Pos.y); } double Asteroid::getRadius() { ci::Vec2f _vec = (getCenter()- Vec2f(15,5)); return _vec.length()*0.3f; }

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• gmetric data submitted doesn't follow dmax value

  - by 580farm

  I have a custom script that is querying a metric port for an application that I'm running and submitting parsed values to ganglia via gmetric. The script runs every minute, so I submit the data to ganglia using the following gmetric options: /usr/sbin/gmetric -g ec2 -s positive -t uint32 -d 600 -n "$NAME" -v $VALUE -x 60 But for some reason there are still gaps in the graphing data: Is there something in my formatting that is preventing the dmax/ttl of the last metric received from being honored? Is there anyone who does custom metric collection that has run into this problem before that can shed some insight or provide some tips as to how to best correct this?

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• Apache mod_header rule to change all cookies to secure

  - by Supowski

  I would like to change all cookies to be secure and http-only. It works fine for one cookie, but doesn't work when multiple cookies are set in response. Apache mod_header rule should change cookies from: Set-Cookie cookie1=value; Path=/somePath Set-Cookie cookie2=value; Path=/somePath to Set-Cookie cookie1=value; Path=/somePath; Secure; Http-Only Set-Cookie cookie2=value; Path=/somePath; Secure; Http-Only I use mod_headers for it with following rule: Header edit Set-Cookie ^(.*)$ $1;Secure;HttpOnly It works fine when only one cookie is set, but if there is more than one, it just removes all the following and they are not set at all. Any help how to write mod_headers rule for multiple values? or the problem is in something else?

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• What problem does double or triple buffering solve in modern games?

  - by krokvskrok

  I want to check if my understanding of the causes for using double (or triple) buffering is correct: A monitor with 60Hz refresh's the monitor-display 60 times per second. If the monitor refresh the monitor-display, he updates pixel for pixel and line for line. The monitor requests the color values for the pixels from the video memory. If I run now a game, then this game is constantly manipulating this video memory. If this game don't use a buffer strategy (double buffering etc.) then the following problem can happen: The monitor is now refreshing his monitor-display. At this moment the monitor had refreshed the first half monitor-display already. At the same time, the game had manipulated the video memory with new data. Now the monitor accesses for the second half monitor-display this new manipulated data from the video memory. The problems can be tearing or flickering. Is my understanding of cases of using buffer strategy correct? Are there other reasons?

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• Intermittent sound

  - by ej159

  The sound on my machine (Medion Akoya S5610) works intermittently. If I reboot enough times I do get sound. This happened before I upgraded, when running Oneiric too. I have fiddled around with alsa-base.conf, putting in different values for model in options snd-hda-intel model=but still the issue persists (although I get the impression that I am more like to have sound on the next reboot if I have edited that file although I can't be sure of this). Adding index=0 does not help the situation either. I have been thinking that this problem could be related some how to the order that driver modules are loaded. The snd-hda-intel module is also used for the sound card (ALC888) in my graphics card. Could it be that these are some how competing? If so, how do I add a preference when they are using the same module? This is the result of lspci -nn | grep Audio (when sound was not working): 00:1b.0 Audio device [0403]: Intel Corporation 82801I (ICH9 Family) HD Audio Controller [8086:293e] (rev 03) 01:00.1 Audio device [0403]: Advanced Micro Devices [AMD] nee ATI RV620 HDMI Audio [Radeon HD 3400 Series] [1002:aa28] I've been wrestling with this problem for ages and ages and have spent days looking for answers on forums but to no avail so I would appreciate any help you can give. Many thanks

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• how does HDR work?

  - by dotminic

  I'm trying to understand what HDR is and how it works. I understand the basic concepts and have an slight idea of how it is implemented with D3D/hlsl. However it's still pretty foggy. Say I'm rendering a sphere with a texture of the earth and a small point list of vertices to act as stars, how would I render this in HDR ? Here are a few things I'm confused about: I'm guessing, I can't use just any basic image format for the texture as the values would be limited to [0, 255] and clamped to [0, 1] in a shader. Same goes for the back buffer, I take it the format needs to be a float point format ? What are the other steps involved ? Surely there has to be more than just using floating point formats to render to a render target and then apply some bloom as a post process ? (considering the output will be 8bpp anyway) Basically, what are the steps for HDR ? How does it work ? I can't seem to find any good papers / articles that describe the process, other than this one, but it seems to skim over the basics a little, so it's confusing.

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• Excel - Disable AutoFormatting on Import

  - by Philip Wales

  How can I stop Microsoft Excel from auto formatting data when imported from a text file? Specifically, I want it to treat all of the values as text. I am auditing insurance data in excel before it is uploaded to the new database. The files come to me as tab delimited text files. When loaded, Excel auto-formats the data causing leading 0's on Zip Codes, Routing Numbers and other codes, to be chopped off. I don't have the patience to reformat all of the columns as text and guess how many zeros need to be replaced. Nor do I want to click through the import wizard an specify that each column is text. Ideally I just want to turn off Excel's Auto-Formatting completely, and just edit every cell as it were plain text. I don't do any formula's or charts, just grid plain text editing.

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• Nullable types and ?? operator C# [en-US]

  - by ruimachado

  Nullable types vs Non-nullable types   While developing our C# projects its frequent the null comparison operation to avoid null exceptions. This simple operation is mainly coded using the "var x = null" code example inside an if clause. However not all types of variables are nullable, which means that setting a variable to null is not allowed in every cases, it depends on what kind of type are you defining. But what if there was an extension to your non-nullable type that would convert your variable types to nullable? This extension really exists. As I said before in C# you have nullable types which represent all the values of an underlying type, and an additional null value and can be declared easily using "T?", where T is the type of the variable and for example the normal int type cannot be null, so its a non-nullable type, however if you define a "int?" your variable can be null, what you do is convert a non-nullable type to a nullable type. Example: int x=null;     Not allowed     int? x=null;   Allowed     While using nullable types you can check if a variable is null the same way you do it with nullable types:     But what about setting a default value when a certain variable is null?   In this cases the c# .net framework let you set a default value when you try to assign a nullable type to a non-nullable type, using the ?? operator. If you don't use this operator you can still catch the InvalidOperationException which is throw in this cases. For example  without the ?? operator :     Using the ?? operator your code becomes cleaner and more easy to read and you get a bonus, you can set a default value for multiple variables using the ?? in a chain set.     That’s it,   Thanks, Rui Machado rpmachado.wordpress.com

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• Override methods should call base method?

  - by Trevor Pilley

  I'm just running NDepend against some code that I have written and one of the warnings is Overrides of Method() should call base.Method(). The places this occurs are where I have a base class which has virtual properties and methods with default behaviour but which can be overridden by a class which inherits from the base class and doesn't call the overridden method. For example, in the base class I have a property defined like this: protected virtual char CloseQuote { get { return '"'; } } And then in an inheriting class which uses a different close quote: protected override char CloseQuote { get { return ']'; } } Not all classes which inherit from the base class use different quote characters hence my initial design. The alternatives I thought of were have get/set properties in the base class with the defaults set in the constructor: protected BaseClass() { this.CloseQuote = '"'; } protected char CloseQuote { get; set; } public InheritingClass() { this.CloseQuote = ']'; } Or make the base class require the values as constructor args: protected BaseClass(char closeQuote, ...) { this.CloseQuote = '"'; } protected char CloseQuote { get; private set; } public InheritingClass() base (closeQuote: ']', ...) { } Should I use virtual in a scenario where the base implementation may be replaced instead of extended or should I opt for one of the alternatives I thought of? If so, which would be preferable and why?

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• IDirect3DDevice9::GetRenderTargetData() returns no data

  - by P. Avery

  I've got a simple function to get the rendertarget data of an RT( w/default pool ). This particular RT has a resolution of 1x1( it's the 10'th and final mip of a texture ). Here is my code to get data for IDirect3DSurface9 *pTargetSurface: IDirect3DSurface9 *pSOS = NULL; pd3dDevice->CreateOffScreenPlainSurface( 1, 1, D3DFMT_A8R8G8B8, D3DPOOL_SYSTEMMEM, &pSOS, NULL ); // get residual energy if( FAILED( hr = pd3dDevice->GetRenderTargetData( pTargetSurface, pSOS ) ) ) { DebugStringDX( ClassName, "Failed to IDirect3DDevice9::GetRenderTargetData() at DownsampleArea()", __LINE__, hr ); goto Exit; } // lock surface if( FAILED( hr = pSOS->LockRect( &rct, NULL, D3DLOCK_READONLY ) ) ) { DebugStringDX( ClassName, "Failed to IDirect3DSurface9::LockRect() at DownsampleArea()", __LINE__, hr ); goto Exit; } // get residual energy from downsampled texture pByte = ( BYTE* )rct.pBits; D3DXVECTOR4 vEnergy; vEnergy.z = ( float )pByte[ 0 ] / 255.0f; vEnergy.y = ( float )pByte[ 1 ] / 255.0f; vEnergy.x = ( float )pByte[ 2 ] / 255.0f; vEnergy.w = ( float )pByte[ 3 ] / 255.0f; V( pSOS->UnlockRect() ); All formatting and settings are correct, directx in debug mode shows no errors... The problem is that the 4 bytes above are 0...I know this to be incorrect by using PIX to debug...PIX shows that RGB bytes are 0.078 and Alpah is 1. These values are not less than that which can be represented by a single byte( 1 / 255 ). Any ideas? Am I copying rendertarget data correctly?

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• selecting files in windows-7 explorer just by hovering

  - by bortao

  One of the biggest annoyances for me of Windows 7 vs Windows XP is that you cant select files properly by hovering over them on Windows Explorer (or multi select by holding ctrl). When i hover an item it gets light blue, not selected. Only after a time or after more hovering, it gets selected. I set the delay (MouseHoverTime) to 1. Windows seems to avoid wrong selection by requiring an additional time or space of mouse hovering before actually selecting the item. I tried playing with the values MouseHoverHeight, MouseHoverWidth, MouseSensitivity, MouseThreshold1 and MouseThreshold2 in HKEY_CURRENT_USER\Control Panel\Mouse, but they seem to have no effect over this. (they are currently on (20, 20, 16, 6, 10, respectively). What i want: to immediately select an item whenever the mouse gets over its bounds.

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