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  • what's the difference between Routed Events and Attached Events?

    - by vverma01
    I tried to find through various sources but still unable to understand difference between routed events and attached events in WPF. Most of the places of reference for attached event following example is used: <StackPanel Button.Click="StackPanel_Click"> <Button Content="Click Me!" Height="35" Width="150" Margin="5" /> </StackPanel> Explained as: stack panel do not contain Click event and hence Button.Click event is attached to Stack Panel. Where as msdn says: You can also name any event from any object that is accessible through the default namespace by using a typename.event partially qualified name; this syntax supports attaching handlers for routed events where the handler is intended to handle events routing from child elements, but the parent element does not also have that event in its members table. This syntax resembles an attached event syntax, but the event here is not a true attached event. Instead, you are referencing an event with a qualified name. According to MSDN information as pasted above, the above example of Buttons and StackPanel is actually a routed event example and not true attached event example. In case if above example is truly about usage of attached event (Button.Click="StackPanel_Click") then it's in contradiction to the information as provided at MSDN which says Another syntax usage that resembles typename.eventname attached event syntax but is not strictly speaking an attached event usage is when you attach handlers for routed events that are raised by child elements. You attach the handlers to a common parent, to take advantage of event routing, even though the common parent might not have the relevant routed event as a member. A similar question was raised in this Stack Overflow post, but unfortunately this question was closed before it could collect any response. Please help me to understand how attached events are different from routed events and also clarify the ambiguity as pointed above.

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  • slow virtualbox guest

    - by ecoologic
    I run a guest ubuntu 12.04 on a host ubuntu 12.04, with virtual box, and the guest is much, much slower than the host (ALT+TAB costs 4-5secs). I had a look around and I found contradicting opinions on virtualbox vs vmware (free), so I taught to keep the former. Both systems are updated, I installed the additions on the guest and I evenly split memory and video memory (64mb) between guest and host. I am running a toshiba m200 laptop with 4GB ram and shared video memory. The host bios does not include a configuration option for machine virtualization. I have 2 cpus and I can't give them both to the vm. Is there anything I overlooked that could solve my problem? Feel free to ask for more info, and thank you for any help. EDIT Idling with the monitor open the (single) guest cpu never gets below 55% and could raise to 80 - 90% just moving the mouse around, opening ff will cause the monitor to run 100% in the guest, while the host shows that both cpus are evenly working around 60%. My cpu is Intel® Core™2 Duo CPU T5450 @ 1.66GHz × 2. If this is not a configuration problem, does it mean my machine is too weak for virtualization?

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  • Using ConcurrentQueue for thread-safe Performance Bookkeeping.

    - by Strenium
    Just a small tidbit that's sprung up today. I had to book-keep and emit diagnostics for the average thread performance in a highly-threaded code over a period of last X number of calls and no more. Need of the day: a thread-safe, self-managing stats container. Since .NET 4.0 introduced new thread-safe 'Collections.Concurrent' objects and I've been using them frequently - the one in particular seemed like a good fit for storing each threads' performance data - ConcurrentQueue. But I wanted to store only the most recent X# of calls and since the ConcurrentQueue currently does not support size constraint I had to come up with my own generic version which attempts to restrict usage to numeric types only: unfortunately there is no IArithmetic-like interface which constrains to only numeric types – so the constraints here here aren't as elegant as they could be. (Note the use of the Average() method, of course you can use others as well as make your own).   FIFO FixedSizedConcurrentQueue using System;using System.Collections.Concurrent;using System.Linq; namespace xxxxx.Data.Infrastructure{    [Serializable]    public class FixedSizedConcurrentQueue<T> where T : struct, IConvertible, IComparable<T>    {        private FixedSizedConcurrentQueue() { }         public FixedSizedConcurrentQueue(ConcurrentQueue<T> queue)        {            _queue = queue;        }         ConcurrentQueue<T> _queue = new ConcurrentQueue<T>();         public int Size { get { return _queue.Count; } }        public double Average { get { return _queue.Average(arg => Convert.ToInt32(arg)); } }         public int Limit { get; set; }        public void Enqueue(T obj)        {            _queue.Enqueue(obj);            lock (this)            {                T @out;                while (_queue.Count > Limit) _queue.TryDequeue(out @out);            }        }    } }   The usage case is straight-forward, in this case I’m using a FIFO queue of maximum size of 200 to store doubles to which I simply Enqueue() the calculated rates: Usage var RateQueue = new FixedSizedConcurrentQueue<double>(new ConcurrentQueue<double>()) { Limit = 200 }; /* greater size == longer history */   That’s about it. Happy coding!

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  • cannot boot ubuntu 13.10 with my usb, Can i change the kernal on my laptop to run it?

    - by Carlos Dunick
    Currently i am running 12.04 and looking for an upgrade to 13.10 I first tried a bootable 64bit usb and failed. With the message saying "Kernal requires an x86-64 CPU but only detected an I686 CPU Unable to boot please use a kernal appropriate for your CPU" then tried 32bit and same message came up. Is this due to my laptop simply being to slow? or can/should i change the kernal somehow? Acer Aspire 5710z Intel Pentium dual core processor, 1.73Ghz, 533 MHz FSB, 1 MB L2 cache. 2GB DDR2 lspci 00:00.0 Host bridge: Intel Corporation Mobile 945GM/PM/GMS, 943/940GML and 945GT Express Memory Controller Hub (rev 03) 00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03) 00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03) 00:1b.0 Audio device: Intel Corporation NM10/ICH7 Family High Definition Audio Controller (rev 02) 00:1c.0 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 1 (rev 02) 00:1c.2 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 3 (rev 02) 00:1c.3 PCI bridge: Intel Corporation NM10/ICH7 Family PCI Express Port 4 (rev 02) 00:1d.0 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #1 (rev 02) 00:1d.1 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #2 (rev 02) 00:1d.2 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #3 (rev 02) 00:1d.3 USB controller: Intel Corporation NM10/ICH7 Family USB UHCI Controller #4 (rev 02) 00:1d.7 USB controller: Intel Corporation NM10/ICH7 Family USB2 EHCI Controller (rev 02) 00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev e2) 00:1f.0 ISA bridge: Intel Corporation 82801GBM (ICH7-M) LPC Interface Bridge (rev 02) 00:1f.1 IDE interface: Intel Corporation 82801G (ICH7 Family) IDE Controller (rev 02) 00:1f.2 SATA controller: Intel Corporation 82801GBM/GHM (ICH7-M Family) SATA Controller [AHCI mode] (rev 02) 00:1f.3 SMBus: Intel Corporation NM10/ICH7 Family SMBus Controller (rev 02) 04:00.0 Ethernet controller: Broadcom Corporation NetLink BCM5787M Gigabit Ethernet PCI Express (rev 02) 05:00.0 Network controller: Broadcom Corporation BCM4311 802.11b/g WLAN (rev 01) 06:00.0 FLASH memory: ENE Technology Inc ENE PCI Memory Stick Card Reader Controller 06:00.1 SD Host controller: ENE Technology Inc ENE PCI SmartMedia / xD Card Reader Controller 06:00.2 FLASH memory: ENE Technology Inc Memory Stick Card Reader Controller 06:00.3 FLASH memory: ENE Technology Inc ENE PCI Secure Digital / MMC Card Reader Controller

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  • Information about rendering, batches, the graphical card, performance etc. + XNA?

    - by Aidiakapi
    I know the title is a bit vague but it's hard to describe what I'm really looking for, but here goes. When it comes to CPU rendering, performance is mostly easy to estimate and straightforward, but when it comes to the GPU due to my lack of technical background information, I'm clueless. I'm using XNA so it'd be nice if theory could be related to that. So what I actually wanna know is, what happens when and where (CPU/GPU) when you do specific draw actions? What is a batch? What influence do effects, projections etc have? Is data persisted on the graphics card or is it transferred over every step? When there's talk about bandwidth, are you talking about a graphics card internal bandwidth, or the pipeline from CPU to GPU? Note: I'm not actually looking for information on how the drawing process happens, that's the GPU's business, I'm interested on all the overhead that precedes that. I'd like to understand what's going on when I do action X, to adapt my architectures and practices to that. Any articles (possibly with code examples), information, links, tutorials that give more insight in how to write better games are very much appreciated. Thanks :)

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  • Interface (contract), Generics (universality), and extension methods (ease of use). Is it a right design?

    - by Saeed Neamati
    I'm trying to design a simple conversion framework based on these requirements: All developers should follow a predefined set of rules to convert from the source entity to the target entity Some overall policies should be able to be applied in a central place, without interference with developers' code Both the creation of converters and usage of converter classes should be easy To solve these problems in C# language, A thought came to my mind. I'm writing it here, though it doesn't compile at all. But let's assume that C# compiles this code: I'll create a generic interface called IConverter public interface IConverter<TSource, TTarget> where TSource : class, new() where TTarget : class, new() { TTarget Convert(TSource source); List<TTarget> Convert(List<TSource> sourceItems); } Developers would implement this interface to create converters. For example: public class PhoneToCommunicationChannelConverter : IConverter<Phone, CommunicationChannle> { public CommunicationChannel Convert(Phone phone) { // conversion logic } public List<CommunicationChannel> Convert(List<Phone> phones) { // conversion logic } } And to make the usage of this conversion class easier, imagine that we add static and this keywords to methods to turn them into Extension Methods, and use them this way: List<Phone> phones = GetPhones(); List<CommunicationChannel> channels = phones.Convert(); However, this doesn't even compile. With those requirements, I can think of some other designs, but they each lack an aspect. Either the implementation would become more difficult or chaotic and out of control, or the usage would become truly hard. Is this design right at all? What alternatives I might have to achieve those requirements?

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  • How Do Computers Work? [closed]

    - by Rob P.
    This is almost embarrassing ask...I have a degree in Computer Science (and a second one in progress). I've worked as a full-time .NET Developer for nearly five years. I generally seem competent at what I do. But I Don't Know How Computers Work! Please, bare with me for a second. A quick Google of 'How a Computer Works' will yield lots and lots of results, but I struggled to find one that really answered what I'm looking for. I realize this is a huge, huge question, so really, if you can just give me some keywords or some direction. I know there are components....the power supply, the motherboard, ram, CPU, etc...and I get the 'general idea' of what they do. But I really don't understand how you go from a line of code like Console.Readline() in .NET (or Java or C++) and have it actually do stuff. Sure, I'm vaguely aware of MSIL (in the case of .NET), and that some magic happens with the JIT compiler and it turns into native code (I think). I'm told Java is similar, and C++ cuts out the middle step. I've done some mainframe assembly, it was a few years back now. I remember there were some instructions and some CPU registers, and I wrote code....and then some magic happened....and my program would work (or crash). From what I understand, an 'Emulator' would simulate what happens when you call an instruction and it would update the CPU registers; but what makes those instructions work the way they do? Does this turn into an Electronics question and not a 'Computer' question? I'm guessing there isn't any practical reason for me to understand this, but I feel like I should be able to. (Yes, this is what happens when you spend a day with a small child. It takes them about 10 minutes and five iterations of asking 'Why?' for you to realize how much you don't know)

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  • Series On Embedded Development (Part 1)

    - by user12612705
    This is the first in a series of entries on developing applications for the embedded environment. Most of this information is relevant to any type of embedded development (and even for desktop and server too), not just Java. This information is based on a talk Hinkmond Wong and I gave at JavaOne 2012 entitled Reducing Dynamic Memory in Java Embedded Applications. One thing to remember when developing embeddded applications is that memory matters. Yes, memory matters in desktop and server environments as well, but there's just plain less of it in embedded devices. So I'm going to be talking about saving this precious resource as well as another precious resource, CPU cycles...and a bit about power too. CPU matters too, and again, in embedded devices, there's just plain less of it. What you'll find, no surprise, is that there's a trade-off between performance and memory. To get better performance, you need to use more memory, and to save more memory, you need to need to use more CPU cycles. I'll be discussing three Memory Reduction Categories: - Optionality, both build-time and runtime. Optionality is about providing options so you can get rid of the stuff you don't need and include the stuff you do need. - Tunability, which is about providing options so you can tune your application by trading performance for size, and vice-versa. - Efficiency, which is about balancing size savings with performance.

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  • ?Oracle DB 11gR2 ?????????????????????????????????????!

    - by Yuichi.Hayashi
    Oracle Database????????????????????????????????????????????????????????????????????????·?????????????????????? ?????????/?????????????????????????????????????11g R2??????????????! ????????? Oracle Database?????????????????????????????????????CPU????·???????????????????????????????????????????????? ?????????????????????????????????????????????? ??????????????????????????????(?????????????·???????)????????????????????????????????????????????????????·?????????????????????????????????????????? ?????????????????????????????????????? ????11g R2??????????????????????????????????????????????? ????????????????? ???????????????????????????????Oracle?????????????????????????????????????? ???????????????????CPU????????????????????????????????????????! Oracle Database????????????????????????????? Oracle ?????? - ??(??), ??, ????? Database Smart Flash Cache Oracle Database??Hard Disk Drive(HDD)???????????????????????SQL??????????????????????????????????????????????????·?????·?????100%??????????????????????????????? ?????????????·??????????CPU????·???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????(????·?????·????????)???????·??????????????????????????? HDD????????????????(???)?????????????????????HDD??IO?????????????????????????? ?????????Solid State Drive/Device(SSD)??? SSD?HDD??????????????????????????????????OLTP????????·??????????????????????????????????????????????????????SSD???????????????????????????? ???11g R2???????????SSD???????????Database Smart Flash Cache????????????Database Smart Flash Cache??????·???????????????????????????(Hot Data)?Oracle?????SSD??????????? ????????!?????????SSD????????????????????SSD????????????????????? SSD???????????????????????????????????? Database Smart Flash Cache?????????????????????? SSD???Oracle???: Database Smart Flash Cache - ??(??), ??, ????? ?????????? ? ???????????????/????????????????!? ? ???????????????????????????????????!?

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  • ????????

    - by Tatsuya Sugi
    ??????????????????? ?????????????????????????????????????????????????????IT?????????????????????????????????????????????????????????????????????? Java ? .NET ????????????????????????????????...????????????????????????????????????????????????????????????????????????????????COBOL??????????????? Java ???????????????????? ??????????Java????????????????????????????? ??/?????????????????????????? ??????????????????????????????????????? ?????????????·?????????????????HW????????/??????? ????????????????????????? ?????????????????????????????????? ??????????????????????? Java ?????????????????? ???????????????????????????????????????????????????????????????????????????????????? ??????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? ??????????????????????????? ??????????????????????????????????????????????????????????(HPC:?????????·?????????)??????????????????????????????????????????????Java??????????????????? ???????????????? ??????????? ?Java + ??????·????????????????????? ??????·?????????????????????????? ?????????·?????????????????????????CPU????????????????????????????????????????????????????????TOP500???????????????8???x86?CPU????????????????????????? ??????·????????·???????????????????????????????/?????????????????????????????????????????????????? ????????????????????? ???: ??????????????/???????????? ?????????????????????????????????????????????????????/???????????????????????????????????????????? ???????: ?????????·????????????????? ????CPU????????????????????????????????·??????????/??????????????????????????????????????????????????????????????????????????????????????????? ??????????????????Java????????????????? ???JVM???????????????? ???????????????????????JVM?????????·????????????? ??????????????????????????????????????????? ??????????????? Oracle Coherence ???????????????????????????????????(??/????????) ??/???????? ???????????? ?????????????????????????????? ????????

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  • useful customize/enhanced php functions that make thing easy and better

    - by I Like PHP
    Hello All, i like to work in php bcoz it's just amazing language. please share basic, useful, enhanced and customize function that make things better and easy in php and must be used in our all PHP project, i m sharing some of them please share your customize function that may be useful for everyone alternative/ enhanced print_r() and var_dump() function watch( $what ) { echo '<pre>'; if ( is_array( $what ) ) { print_r ( $what ); } else { var_dump ( $what ); } echo '</pre>'; } usage: 1. watch($_POST); // to see all post variable 2. watch($array); // to see any variable may b array, string or a variable enhanced mysql_escape_string() for multidimensional array to prevent sql injection function recursive_escape(&$value) { if (is_array($value)) array_map('recursive_escape', $value); else $value = mysql_escape_string($value); } usage array_map('recursive_escape', $_POST); ---------------------For encoding Get variables-------------------------------------- function nkode($k) { if ( is_array( $k ) ) return array_map("base64_encode",$k); else return base64_encode($k); } ---------------------for decoding varaibles from GET--------------------------------- function dkode($k) { if ( is_array( $k ) ) return array_map("base64_decode",$k); else return base64_decode($k); } Usage <a href="somelink.php?pid=<?php echo nkode($someid)?>"> and on next page(somelink.php) $findID=dkode($_GET[pid]); date convert to mm/dd/yyyy to yyyy-mm-dd( if we use date datatype in mysql) and also change into mm/dd/yyyy to disply on page function dateconvert($date,$func) { if ($func == 1){ //insert conversion list($month, $day, $year) = split('[/.-]', $date); $date = "$year-$month-$day"; return $date; } if ($func == 2){ //output conversion list($year, $month, $day) = split('[-.]', $date); $date = "$month/$day/$year"; return $date; } } usage $firstDate=dateconvert($_POST['firstdate'],1); // for insertion in database $showDate=dateconvert($fetch->date_field,2) // to display on browser to clean(sql injection proof) data before doing some action with that variable function cleandata($data) { $success=0; $data=trim($data); $data=strtolower($data); $data=strip_tags($data); return $data; } usage cleandata($_POST[username]); cleandata($_GET[pid]); please share any basic function that must be used , Thanks

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  • What are those little useful ,customize/enhanced php functions that you wish you knew about 2 years

    - by I Like PHP
    Hello All, i like to work in php bcoz it's just amazing language. please share basic, useful, enhanced and customize function that make things better and easy in php and must be used in our all PHP project, i m sharing some of them please share your customize function that may be useful for everyone alternative/ enhanced print_r() and var_dump() function watch( $what ) { echo '<pre>'; if ( is_array( $what ) ) { print_r ( $what ); } else { var_dump ( $what ); } echo '</pre>'; } usage: 1. watch($_POST); // to see all post variable 2. watch($array); // to see any variable may b array, string or a variable enhanced mysql_escape_string() for multidimensional array to prevent sql injection function recursive_escape(&$value) { if (is_array($value)) array_map('recursive_escape', $value); else $value = mysql_escape_string($value); } usage array_map('recursive_escape', $_POST); ---------------------For encoding Get variables-------------------------------------- function nkode($k) { if ( is_array( $k ) ) return array_map("base64_encode",$k); else return base64_encode($k); } ---------------------for decoding varaibles from GET--------------------------------- function dkode($k) { if ( is_array( $k ) ) return array_map("base64_decode",$k); else return base64_decode($k); } Usage <a href="somelink.php?pid=<?php echo nkode($someid)?>"> and on next page(somelink.php) $findID=dkode($_GET[pid]); date convert to mm/dd/yyyy to yyyy-mm-dd( if we use date datatype in mysql) and also change into mm/dd/yyyy to disply on page function dateconvert($date,$func) { if ($func == 1){ //insert conversion list($month, $day, $year) = split('[/.-]', $date); $date = "$year-$month-$day"; return $date; } if ($func == 2){ //output conversion list($year, $month, $day) = split('[-.]', $date); $date = "$month/$day/$year"; return $date; } } usage $firstDate=dateconvert($_POST['firstdate'],1); // for insertion in database $showDate=dateconvert($fetch->date_field,2) // to display on browser to clean data before doing some action with that variable function cleanID($data) { $success=0; $data=trim($data); $data=strtolower($data); $data=strip_tags($data); return $data; } usage cleanID($_POST[username]); cleanID($_GET[pid]); please share any basic function that must be used , and please give me some suggestion to make above function more better Thanks

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  • output with "Private`" Content in Mathematica Package

    - by madalina
    Hello everyone, I am trying to solve the following implementation problem in Mathematica 7.0 for some days now and I do not understand exactly what is happening so I hope someone can give me some hints. I have 3 functions that I implemented in Mathematica in a source file with extension *.nb. They are working okay to all the examples. Now I want to put these functions into 3 different packages. So I created three different packages with extension .*m in which I put all the desired Mathematica function. An example in the "stereographic.m" package which contain the code: BeginPackage["stereographic`"] stereographic::usage="The package stereographic...." formEqs::usage="The function formEqs[complexBivPolyEqn..." makePoly::usage="The function makePoly[algebraicEqn] ..." getFixPolys::usage="The function..." milnorFibration::usage="The function..." Begin["Private`"] Share[]; formEqs[complex_,{m_,n_}]:=Block[{complexnew,complexnew1, realeq, imageq, expreal, expimag, polyrealF, polyimagF,s,t,u,v,a,b,c,epsilon,x,y,z}, complexnew:=complex/.{m->s+I*t,n->u+I*v}; complexnew1:=complexnew/.{s->(2 a epsilon)/(1+a^2+b^2+c^2),t->(2 b epsilon)/(1+a^2+b^2+c^2),u->(2 c epsilon)/(1+a^2+b^2+c^2),v->(- epsilon+a^2 epsilon+b^2 epsilon+c^2 epsilon)/(1+a^2+b^2+c^2)}; realeq:=ComplexExpand[Re[complexnew1]]; imageq:=ComplexExpand[Im[complexnew1]]; expreal:=makePoly[realeq]; expimag:=makePoly[imageq]; polyrealF:=expreal/.{a->x,b->y,c->z}; polyimagF:=expimag/.{a->x,b->y,c->z}; {polyrealF,polyimagF} ] End[] EndPackage[] Now to test the function I load the package Needs["stereographic`"] everything is okay. But when I test the function for example with formEqs[x^2-y^2,{x,y}] I get the following ouput: {Private`epsilon^2 + 2 Private`x^2 Private`epsilon^2 + Private`x^4 Private`epsilon^2 - 6 Private`y^2 Private`epsilon^2 + 2 Private`x^2 Private`y^2 Private`epsilon^2 + Private`y^4 Private`epsilon^2 - 6 Private`z^2 Private`epsilon^2 + 2 Private`x^2 Private`z^2 Private`epsilon^2 + 2 Private`y^2 Private`z^2 Private`epsilon^2 + Private`z^4 Private`epsilon^2, 8 Private`x Private`y Private`epsilon^2 + 4 Private`z Private`epsilon^2 - 4 Private`x^2 Private`z Private`epsilon^2 - 4 Private`y^2 Private`z Private`epsilon^2 - 4 Private`z^3 Private`epsilon^2} Of course I do not understand why Private` appears in front of any local variable which I returned in the final result. I would want not to have this Private` in the computed output. Any idea or better explanations which could indicate me why this happens? Thank you very much for your help. Best wishes, madalina

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  • ZFS for Database Log Files

    - by user12620111
    I've been troubled by drop outs in CPU usage in my application server, characterized by the CPUs suddenly going from close to 90% CPU busy to almost completely CPU idle for a few seconds. Here is an example of a drop out as shown by a snippet of vmstat data taken while the application server is under a heavy workload. # vmstat 1  kthr      memory            page            disk          faults      cpu  r b w   swap  free  re  mf pi po fr de sr s3 s4 s5 s6   in   sy   cs us sy id  1 0 0 130160176 116381952 0 16 0 0 0 0  0  0  0  0  0 207377 117715 203884 70 21 9  12 0 0 130160160 116381936 0 25 0 0 0 0 0  0  0  0  0 200413 117162 197250 70 20 9  11 0 0 130160176 116381920 0 16 0 0 0 0 0  0  1  0  0 203150 119365 200249 72 21 7  8 0 0 130160176 116377808 0 19 0 0 0 0  0  0  0  0  0 169826 96144 165194 56 17 27  0 0 0 130160176 116377800 0 16 0 0 0 0  0  0  0  0  1 10245 9376 9164 2  1 97  0 0 0 130160176 116377792 0 16 0 0 0 0  0  0  0  0  2 15742 12401 14784 4 1 95  0 0 0 130160176 116377776 2 16 0 0 0 0  0  0  1  0  0 19972 17703 19612 6 2 92  14 0 0 130160176 116377696 0 16 0 0 0 0 0  0  0  0  0 202794 116793 199807 71 21 8  9 0 0 130160160 116373584 0 30 0 0 0 0  0  0 18  0  0 203123 117857 198825 69 20 11 This behavior occurred consistently while the application server was processing synthetic transactions: HTTP requests from JMeter running on an external machine. I explored many theories trying to explain the drop outs, including: Unexpected JMeter behavior Network contention Java Garbage Collection Application Server thread pool problems Connection pool problems Database transaction processing Database I/O contention Graphing the CPU %idle led to a breakthrough: Several of the drop outs were 30 seconds apart. With that insight, I went digging through the data again and looking for other outliers that were 30 seconds apart. In the database server statistics, I found spikes in the iostat "asvc_t" (average response time of disk transactions, in milliseconds) for the disk drive that was being used for the database log files. Here is an example:                     extended device statistics     r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 2053.6    0.0 8234.3  0.0  0.2    0.0    0.1   0  24 c3t60080E5...F4F6d0s0     0.0 2162.2    0.0 8652.8  0.0  0.3    0.0    0.1   0  28 c3t60080E5...F4F6d0s0     0.0 1102.5    0.0 10012.8  0.0  4.5    0.0    4.1   0  69 c3t60080E5...F4F6d0s0     0.0   74.0    0.0 7920.6  0.0 10.0    0.0  135.1   0 100 c3t60080E5...F4F6d0s0     0.0  568.7    0.0 6674.0  0.0  6.4    0.0   11.2   0  90 c3t60080E5...F4F6d0s0     0.0 1358.0    0.0 5456.0  0.0  0.6    0.0    0.4   0  55 c3t60080E5...F4F6d0s0     0.0 1314.3    0.0 5285.2  0.0  0.7    0.0    0.5   0  70 c3t60080E5...F4F6d0s0 Here is a little more information about my database configuration: The database and application server were running on two different SPARC servers. Storage for the database was on a storage array connected via 8 gigabit Fibre Channel Data storage and log file were on different physical disk drives Reliable low latency I/O is provided by battery backed NVRAM Highly available: Two Fibre Channel links accessed via MPxIO Two Mirrored cache controllers The log file physical disks were mirrored in the storage device Database log files on a ZFS Filesystem with cutting-edge technologies, such as copy-on-write and end-to-end checksumming Why would I be getting service time spikes in my high-end storage? First, I wanted to verify that the database log disk service time spikes aligned with the application server CPU drop outs, and they did: At first, I guessed that the disk service time spikes might be related to flushing the write through cache on the storage device, but I was unable to validate that theory. After searching the WWW for a while, I decided to try using a separate log device: # zpool add ZFS-db-41 log c3t60080E500017D55C000015C150A9F8A7d0 The ZFS log device is configured in a similar manner as described above: two physical disks mirrored in the storage array. This change to the database storage configuration eliminated the application server CPU drop outs: Here is the zpool configuration: # zpool status ZFS-db-41   pool: ZFS-db-41  state: ONLINE  scan: none requested config:         NAME                                     STATE         ZFS-db-41                                ONLINE           c3t60080E5...F4F6d0  ONLINE         logs           c3t60080E5...F8A7d0  ONLINE Now, the I/O spikes look like this:                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1053.5    0.0 4234.1  0.0  0.8    0.0    0.7   0  75 c3t60080E5...F8A7d0s0                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1131.8    0.0 4555.3  0.0  0.8    0.0    0.7   0  76 c3t60080E5...F8A7d0s0                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1167.6    0.0 4682.2  0.0  0.7    0.0    0.6   0  74 c3t60080E5...F8A7d0s0     0.0  162.2    0.0 19153.9  0.0  0.7    0.0    4.2   0  12 c3t60080E5...F4F6d0s0                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1247.2    0.0 4992.6  0.0  0.7    0.0    0.6   0  71 c3t60080E5...F8A7d0s0     0.0   41.0    0.0   70.0  0.0  0.1    0.0    1.6   0   2 c3t60080E5...F4F6d0s0                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1241.3    0.0 4989.3  0.0  0.8    0.0    0.6   0  75 c3t60080E5...F8A7d0s0                     extended device statistics                  r/s    w/s   kr/s   kw/s wait actv wsvc_t asvc_t  %w  %b device     0.0 1193.2    0.0 4772.9  0.0  0.7    0.0    0.6   0  71 c3t60080E5...F8A7d0s0 We can see the steady flow of 4k writes to the ZIL device from O_SYNC database log file writes. The spikes are from flushing the transaction group. Like almost all problems that I run into, once I thoroughly understand the problem, I find that other people have documented similar experiences. Thanks to all of you who have documented alternative approaches. Saved for another day: now that the problem is obvious, I should try "zfs:zfs_immediate_write_sz" as recommended in the ZFS Evil Tuning Guide. References: The ZFS Intent Log Solaris ZFS, Synchronous Writes and the ZIL Explained ZFS Evil Tuning Guide: Cache Flushes ZFS Evil Tuning Guide: Tuning ZFS for Database Performance

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  • SQLAuthority News – SQL Server Technical Article – The Data Loading Performance Guide

    - by pinaldave
    The white paper describes load strategies for achieving high-speed data modifications of a Microsoft SQL Server database. “Bulk Load Methods” and “Other Minimally Logged and Metadata Operations” provide an overview of two key and interrelated concepts for high-speed data loading: bulk loading and metadata operations. After this background knowledge, white paper describe how these methods can be [...]

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  • Networking middleware

    - by Howie
    I'm looking for a networking middleware that may be suitable for a medium-sized MMO. I don't care in which language it's written, just that it's high-level, stable and has many of the features that can ease my development. I am making a 2D real-time action game. Come to think of it... I'd be happy with "just" a high-level networking framework that has a few handy features to ease the development of a general networked game.

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  • links for 2010-12-16

    - by Bob Rhubart
    Oracle Solaris 11 Express: Network Virtualization and Resource Control | Oracle Clinic XiangBingLiu's detailed overview of Oracle Solaris 11 Express features, including Crossbow. (tags: oracle solaris virtualization crossbow) A New Threat To Web Applications: Connection String Parameter Pollution (CSPP) (The Oracle Global Product Security Blog) "CSPP, if carried out successfully, can be used to steal user identities and hijack web credentials. CSPP is a high risk attack because of the relative ease with which it can be carried out (low access complexity) and the potential results it can have (high impact)." -- Shaomin Wang (tags: oracle otn security cspp)

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  • SQLAuthority News – Android Efficiency Tips and Tricks – Personal Technology Tip #003

    - by pinaldave
    I use my phone for lots of things.  I use it mainly to replace my tablet – I can e-mail, take and edit photos, and do almost everything I can do on a laptop with this phone.  And I am sure that there are many of you out there just like me.  I personally have a Galaxy S3, which uses the Android operating system, and I have decided to feature it as the third installment of my Technology Tips and Tricks series. 1) Shortcut to your favorite contacts on home screen Access your most-called contacts easily from your home screen by holding your finger on any empty spot on the home screen.  A menu will pop up that allows you to choose Shortcuts, and Contact.  You can scroll through your contact list and then just tap on the name of the person you want to be able to dial with a single click. 2) Keep track of your data usage Yes, we all should keep a close eye on our data usage, because it is very easy to go over our limits and then end up with a giant bill at the end of the month.  Never get surprised when you open that mobile phone envelope again.  Go to Settings, then Data Usage, and you can find a quick rundown of your usage, how much data each app uses, and you can even set alarms to let you know when you are nearing the limits.   Better yet, you can set the phone to stop using data when it reaches a certain limit. 3) Bring back Good Grammar We often hear proclamations about the downfall of written language, and how texting abbreviations, misspellings, and lack of punctuation are the root of all evil.  Well, we can show all those doomsdayers that all is not lost by bringing punctuation back to texting.  Usually we leave it off when we text because it takes too long to get to the screen with all the punctuation options.  But now you can hold down the period (or “full stop”) button and a list of all the commonly-used punctuation marks will pop right up. 4) Apps, Apps, Apps and Apps And finally, I cannot end an article about smart phones without including a list of my favorite apps.  Here are a list of my Top 10 Applications on my Android (not counting social media apps). Advanced Task Killer – Keeps my phone snappy by closing un-necessary apps WhatsApp - my favorite alternate to Text SMS Flipboard - my ‘timepass’ moments Skype – keeps me close to friends and family GoogleMaps - I am never lost because of this one thing Amazon Kindle – Books my best friends DropBox - My data always safe Pluralsight Player – Learning never stops for me Samsung Kies Air – Connecting Phone to Computer Chrome – Replacing default browser I have not included any social media applications in the above list, but you can be sure that I am linked to Twitter, Facebook, Google+, LinkedIn, and YouTube. Reference: Pinal Dave (http://blog.SQLAuthority.com)   Filed under: Best Practices, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology Tagged: Android, Personal Technology

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  • SQLAuthority News – Android Efficiency Tips and Tricks – Personal Technology Tip

    - by pinaldave
    I use my phone for lots of things.  I use it mainly to replace my tablet – I can e-mail, take and edit photos, and do almost everything I can do on a laptop with this phone.  And I am sure that there are many of you out there just like me.  I personally have a Galaxy S3, which uses the Android operating system, and I have decided to feature it as the third installment of my Technology Tips and Tricks series. 1) Shortcut to your favorite contacts on home screen Access your most-called contacts easily from your home screen by holding your finger on any empty spot on the home screen.  A menu will pop up that allows you to choose Shortcuts, and Contact.  You can scroll through your contact list and then just tap on the name of the person you want to be able to dial with a single click. 2) Keep track of your data usage Yes, we all should keep a close eye on our data usage, because it is very easy to go over our limits and then end up with a giant bill at the end of the month.  Never get surprised when you open that mobile phone envelope again.  Go to Settings, then Data Usage, and you can find a quick rundown of your usage, how much data each app uses, and you can even set alarms to let you know when you are nearing the limits.   Better yet, you can set the phone to stop using data when it reaches a certain limit. 3) Bring back Good Grammar We often hear proclamations about the downfall of written language, and how texting abbreviations, misspellings, and lack of punctuation are the root of all evil.  Well, we can show all those doomsdayers that all is not lost by bringing punctuation back to texting.  Usually we leave it off when we text because it takes too long to get to the screen with all the punctuation options.  But now you can hold down the period (or “full stop”) button and a list of all the commonly-used punctuation marks will pop right up. 4) Apps, Apps, Apps and Apps And finally, I cannot end an article about smart phones without including a list of my favorite apps.  Here are a list of my Top 10 Applications on my Android (not counting social media apps). Advanced Task Killer – Keeps my phone snappy by closing un-necessary apps WhatsApp - my favorite alternate to Text SMS Flipboard - my ‘timepass’ moments Skype – keeps me close to friends and family GoogleMaps - I am never lost because of this one thing Amazon Kindle – Books my best friends DropBox - My data always safe Pluralsight Player – Learning never stops for me Samsung Kies Air – Connecting Phone to Computer Chrome – Replacing default browser I have not included any social media applications in the above list, but you can be sure that I am linked to Twitter, Facebook, Google+, LinkedIn, and YouTube. Reference: Pinal Dave (http://blog.SQLAuthority.com)   Filed under: Best Practices, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, SQLAuthority News, T SQL, Technology Tagged: Android, Personal Technology

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  • Ha a hutés nem elég a gépteremben: Sun Cooling Door a Database Machine-hoz

    - by Fekete Zoltán
    A Database Machine hatalmas teljesítménye miatt általában jóval kevesebb hutésre van szükség, mintha egy külön high-end servert és külön high-end storage-ot hutenénk! Ha viszont a géptermünk maradék hutési kapacitása nem elegendo, és nem elégszünk meg a "hagyományos mosóporral", akkor újabb hutési trükkre van szükség. Erre kínálnak megoldást a Sun Cooling Door modellek, például az 5200-as és az 5600-as modellek.

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  • Oracle Systems and Solutions at OpenWorld Tokyo 2012

    - by ferhat
    Oracle OpenWorld Tokyo and JavaOne Tokyo will start next week April 4th. We will cover Oracle systems and Oracle Optimized Solutions in several keynote talks and general sessions. Full schedule can be found here. Come by the DemoGrounds to learn more about mission critical integration and optimization of complete Oracle stack. Our Oracle Optimized Solutions experts will be at hand to discuss 1-1 several of Oracle's systems solutions and technologies. Oracle Optimized Solutions are proven blueprints that eliminate integration guesswork by combing best in class hardware and software components to deliver complete system architectures that are fully tested, and include documented best practices that reduce integration risks and deliver better application performance. And because they are highly flexible by design, Oracle Optimized Solutions can be implemented as an end-to-end solution or easily adapted into existing environments. Oracle Optimized Solutions, Servers,  Storage, and Oracle Solaris  Sessions, Keynotes, and General Session Talks DAY TIME TITLE Notes Session Wednesday  April 4 9:00 - 11:15 Keynote: ENGINEERED FOR INNOVATION - Engineered Systems Mark Hurd,  President, Oracle Takao Endo, President & CEO, Oracle Corporation Japan John Fowler, EVP of Systems, Oracle Ed Screven, Chief Corporate Architect, Oracle English Session K1-01 11:50 - 12:35 Simplifying IT: Transforming the Data Center with Oracle's Engineered Systems Robert Shimp, Group VP, Product Marketing, Oracle English Session S1-01 15:20 - 16:05 Introducing Tiered Storage Solution for low cost Big Data Archiving S1-33 16:30 - 17:15 Simplifying IT - IT System Consolidation that also Accelerates Business Agility S1-42 Thursday  April 5 9:30 - 11:15 Keynote: Extreme Innovation Larry Ellison, Chief Executive Officer, Oracle English Session K2-01 11:50 - 13:20 General Session: Server and Storage Systems Strategy John Fowler, EVP of Systems, Oracle English Session G2-01 16:30 - 17:15 Top 5 Reasons why ZFS Storage appliance is "The cloud storage" by SAKURA Internet Inc L2-04 16:30 - 17:15 The UNIX based Exa* Performance IT Integration Platform - SPARC SuperCluster S2-42 17:40 - 18:25 Full stack solutions of hardware and software with SPARC SuperCluster and Oracle E-Business Suite  to minimize the business cost while maximizing the agility, performance, and availability S2-53 Friday April 6 9:30 - 11:15 Keynote: Oracle Fusion Applications & Cloud Robert Shimp, Group VP, Product Marketing Anthony Lye, Senior VP English Session K3-01 11:50 - 12:35 IT at Oracle: The Art of IT Transformation to Enable Business Growth English Session S3-02 13:00-13:45 ZFS Storagge Appliance: Architecture of high efficient and high performance S3-13 14:10 - 14:55 Why "Niko Niko doga" chose ZFS Storage Appliance to support their growing requirements and storage infrastructure By DWANGO Co, Ltd. S3-21 15:20 - 16:05 Osaka University: Lower TCO and higher flexibility for student study by Virtual Desktop By Osaka University S3-33 Oracle Developer Sessions with Oracle Systems and Oracle Solaris DAY TIME TITLE Notes LOCATION Friday April 6 13:00 - 13:45 Oracle Solaris 11 Developers D3-03 13:00 - 14:30 Oracle Solaris Tuning Contest Hands-On Lab D3-04 14:00 - 14:35 How to build high performance and high security Oracle Database environment with Oracle SPARC/Solaris English Session D3-13 15:00 - 15:45 IT Assets preservation and constructive migration with Oracle Solaris virtualization D3-24 16:00 - 17:30 The best packaging system for cloud environment - Creating an IPS package D3-34 Follow Oracle Infrared at Twitter, Facebook, Google+, and LinkedIn  to catch the latest news, developments, announcements, and inside views from  Oracle Optimized Solutions.

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  • SQL SERVER – Speed Up! – Parallel Processes and Unparalleled Performance – TechEd 2012 India

    - by pinaldave
    TechEd India 2012 is just around the corner and I will be presenting there on two different session. SQL Server Performance Tuning is a very challenging subject that requires expertise in Database Administration and Database Development. I always have enjoyed talking about SQL Server Performance tuning subject. Just like doctors I like to call my every attempt to improve the performance of SQL Server queries and database server as a practice too. I have been working with SQL Server for more than 8 years and I believe that many of the performance tuning concept I have mastered. However, performance tuning is not a simple subject. However there are occasions when I feel stumped, there are occasional when I am not sure what should be the next step. When I face situation where I cannot figure things out easily, it makes me most happy because I clearly see this as a learning opportunity. I have been presenting in TechEd India for last three years. This is my fourth time opportunity to present a technical session on SQL Server. Just like every other year, I decided to present something different, something which I have spend years of learning. This time, I am going to present about parallel processes. It is widely believed that more the CPU will improve performance of the server. It is true in many cases. However, there are cases when limiting the CPU usages have improved overall health of the server. I will be presenting on the subject of Parallel Processes and its effects. I have spent more than a year working on this subject only. After working on various queries on multi-CPU systems I have personally learned few things. In coming TechEd session, I am going to share my experience with parallel processes and performance tuning. Session Details Title: Speed Up! – Parallel Processes and Unparalleled Performance (Add to Calendar) Abstract: “More CPU More Performance” – A  very common understanding is that usage of multiple CPUs can improve the performance of the query. To get maximum performance out of any query – one has to master various aspects of the parallel processes. In this deep dive session, we will explore this complex subject with a very simple interactive demo. An attendee will walk away with proper understanding of CX_PACKET wait types, MAXDOP, parallelism threshold and various other concepts. Date and Time: March 23, 2012, 12:15 to 13:15 Location: Hotel Lalit Ashok - Kumara Krupa High Grounds, Bengaluru – 560001, Karnataka, India. Add to Calendar Please submit your questions in the comments area and I will be for sure discussing them during my session. If I pick your question to discuss during my session, here is your gift I commit right now – SQL Server Interview Questions and Answers Book. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: PostADay, SQL, SQL Authority, SQL Performance, SQL Query, SQL Server, SQL Tips and Tricks, SQL Wait Stats, SQL Wait Types, T SQL, Technology Tagged: TechEd, TechEdIn

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  • Does The College Matter?

    - by Jonathon
    Does it matter all that much about what college you go to, to get a degree in computer programming/computer science? I didn't do all that well in high school, I actually barely graduated with a general High School Diploma. So getting into a decent college could be difficult. Companies won't deny you just because you got your degree at a college they have never heard of or a community college will they?

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