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  • MongoDB map reduce count giving more results than a query

    - by giorgiosironi
    I have a collection users in Mongo and I execute this map reduce which I believe is the equivalent of a COUNT(*) GROUP BY origin: > m = function() { for (i in this.membership) { ... emit( this.membership[i].platform_profile.origin, 1 ); ... } } function () { for (i in this.membership) { emit(this.membership[i].platform_profile.origin, 1); } } > r = function( id, values ) { var result = 0; ... for ( var i = 0; i < values.length; i ++ ) { result += values[i]; } ... return result; } function (id, values) { var result = 0; for (var i = 0; i < values.length; i++) { result += values[i]; } return result; } > db.users.mapReduce(m, r, {out : { inline: 1}}); { "results" : [ { "_id" : 0, "value" : 15 }, { "_id" : 1, "value" : 449 }, ... } But if I try to count how many documents have this field set to a specific value like 1, I get fewer results: db.users.count({"membership.platform_profile.origin": 1}); 424 What am I missing?

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  • SQL Server data platform upgrade - Why upgrade and how best you can reduce pre & post upgrade problems?

    - by ssqa.net
    SQL Server upgrade, let it be database(s) or instance(s) or both the process and procedures must follow best practices in order to reduce any problems that may occur even after the platform is upgraded. The success of any project relies upon the simpler methods of implementation and a process to reduce the complexity in testing to ensure a successful outcome. Also the topic has been a popular topic that .... read more from here ......(read more)

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  • What are different ways to reduce latency between a server and a web application? [closed]

    - by jjoensuu
    this is a question about a web application that provides SOAP web services. For the sake of this question, this web app is hosted on a server SERVER B which is located in California. We have an automated, scheduled, process running on a server SERVER A, located in New York. This scheduled process is supposed to send SOAP messages to SERVER B every so often, but this process typically dies soon after starting. We have now been told by the vendor that reason why the process dies is because of the latency between SERVER A and SERVER B. The data traffic is routed through many diffent public networks. There is no dedicated line between SERVER A and SERVER B. As a result I have been asked to look into ways to reduce the latency between SERVER A and SERVER B. So I wanted to ask, what are the different ways to reduce latency in a situation like this? For example, would it help to switch from HTTPS to some other secure protocol? (the thought here is that perhaps some other alternative would require fewer handshakes than HTTPS). Or would a VPN help? If a VPN would reduce the latency, how would it do that? NOTE: I am not looking for an explicit answer that would work in my specific situation. I am more like looking just for a simple list of what technologies could be used for this. I will still have to evaluate the technologies and discuss them internally with others, so the list would just be a starting point. Here I am assuming that there exists very few ways to reduce latency between two servers that communicate across public networks using HTTPS. Feel free to correct me if this assumption is wrong and please ask if there is a need for specific information. NOTE 2: A list of technologies is a specific answer to the question I stated in the title. NOTE 3: Its rather dumb to close this question when it is after all about me looking for information and furthermore this information can clearly be useful for others. Anyway luckily there are other sites where I can ask around. StackExchange seems to attached to their own philosophical principles. Many thanks

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  • Read files from directory to create a ZIP hadoop

    - by Félix
    I'm looking for hadoop examples, something more complex than the wordcount example. What I want to do It's read the files in a directory in hadoop and get a zip, so I have thought to collect al the files in the map class and create the zip file in the reduce class. Can anyone give me a link to a tutorial or example than can help me to built it? I don't want anyone to do this for me, i'm asking for a link with better examples than the wordaccount. This is what I have, maybe it's useful for someone public class Testing { private static class MapClass extends MapReduceBase implements Mapper<LongWritable, Text, Text, BytesWritable> { // reuse objects to save overhead of object creation Logger log = Logger.getLogger("log_file"); public void map(LongWritable key, Text value, OutputCollector<Text, BytesWritable> output, Reporter reporter) throws IOException { String line = ((Text) value).toString(); log.info("Doing something ... " + line); BytesWritable b = new BytesWritable(); b.set(value.toString().getBytes() , 0, value.toString().getBytes() .length); output.collect(value, b); } } private static class ReduceClass extends MapReduceBase implements Reducer<Text, BytesWritable, Text, BytesWritable> { Logger log = Logger.getLogger("log_file"); ByteArrayOutputStream bout; ZipOutputStream out; @Override public void configure(JobConf job) { super.configure(job); log.setLevel(Level.INFO); bout = new ByteArrayOutputStream(); out = new ZipOutputStream(bout); } public void reduce(Text key, Iterator<BytesWritable> values, OutputCollector<Text, BytesWritable> output, Reporter reporter) throws IOException { while (values.hasNext()) { byte[] data = values.next().getBytes(); ZipEntry entry = new ZipEntry("entry"); out.putNextEntry(entry); out.write(data); out.closeEntry(); } BytesWritable b = new BytesWritable(); b.set(bout.toByteArray(), 0, bout.size()); output.collect(key, b); } @Override public void close() throws IOException { // TODO Auto-generated method stub super.close(); out.close(); } } /** * Runs the demo. */ public static void main(String[] args) throws IOException { int mapTasks = 20; int reduceTasks = 1; JobConf conf = new JobConf(Prue.class); conf.setJobName("testing"); conf.setNumMapTasks(mapTasks); conf.setNumReduceTasks(reduceTasks); MultipleInputs.addInputPath(conf, new Path("/messages"), TextInputFormat.class, MapClass.class); conf.setOutputKeyClass(Text.class); conf.setOutputValueClass(BytesWritable.class); FileOutputFormat.setOutputPath(conf, new Path("/czip")); conf.setMapperClass(MapClass.class); conf.setCombinerClass(ReduceClass.class); conf.setReducerClass(ReduceClass.class); // Delete the output directory if it exists already JobClient.runJob(conf); } }

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  • Is there a way of providing a final transform method when chaining operations (like map reduce) in underscore.js?

    - by latentflip
    (Really strugging to title this question, so if anyone has suggestions feel free.) Say I wanted to do an operation like: take an array [1,2,3] multiply each element by 2 (map): [2,4,6] add the elements together (reduce): 12 multiply the result by 10: 120 I can do this pretty cleanly in underscore using chaining, like so: arr = [1,2,3] map = (el) -> 2*el reduce = (s,n) -> s+n out = (r) -> 10*r reduced = _.chain(arr).map(map).reduce(reduce).value() result = out(reduced) However, it would be even nicer if I could chain the 'out' method too, like this: result = _.chain(arr).map(map).reduce(reduce).out(out).value() Now this would be a fairly simple addition to a library like underscore. But my questions are: Does this 'out' method have a name in functional programming? Does this already exist in underscore (tap comes close, but not quite).

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  • Optimisation <xsl:apply-templates/> for a set of tags.

    - by kalininew
    How it is possible to reduce this record? <xsl:template match="BR"> <br/> </xsl:template> <xsl:template match="B"> <strong><xsl:apply-templates /></strong> </xsl:template> <xsl:template match="STRONG"> <strong><xsl:apply-templates /></strong> </xsl:template> <xsl:template match="I"> <em><xsl:apply-templates /></em> </xsl:template> <xsl:template match="EM"> <em><xsl:apply-templates /></em> </xsl:template> <xsl:template match="OL"> <ol><xsl:apply-templates /></ol> </xsl:template> <xsl:template match="UL"> <ul><xsl:apply-templates /></ul> </xsl:template> <xsl:template match="LI"> <li><xsl:apply-templates /></li> </xsl:template> <xsl:template match="SUB"> <sub><xsl:apply-templates /></sub> </xsl:template> <xsl:template match="SUP"> <sup><xsl:apply-templates /></sup> </xsl:template> <xsl:template match="NOBR"> <nobr><xsl:apply-templates /></nobr> </xsl:template>

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  • How to read reduce/shift conflicts in LR(1) DFA?

    - by greenoldman
    I am reading an explanation (awesome "Parsing Techniques" by D.Grune and C.J.H.Jacobs; p.293 in the 2nd edition) and I moved forward from my last question: How to get lookahead symbol when constructing LR(1) NFA for parser? Now I have such "problem" (maybe not a problem, but rather need of confirmation from some more knowledgeable people). The authors present state in LR(0) which has reduce/shift conflict. Then they build DFA for LR(1) for the same grammar. And now they say it does not have a conflict (lookaheads at the end): S -> E . eof E -> E . - T eof E -> E . - T - and there is an edge from this state labeled - but no labeled eof. Authors says, that on eof there will be reduce, on - there will be shift. However eof is for shift as well (as lookahead). So my personal understanding of LR(1) DFA is this -- you can drop lookaheads for shifts, because they serve no purpose now -- shifts rely on input, not on lookaheads -- and after that, remove duplicates. S -> E . eof E -> E . - T So the lookahead for reduce serves as input really, because at this stage (all required input is read) it is really incoming symbol right now. For shifts, the input symbols are on the edges. So my question is this -- am I actually right about dropping lookaheads for shifts (after fully constructing DFA)?

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  • How to reduce iOS AVPlayer start delay

    - by Bernt Habermeier
    Note, for the below question: All assets are local on the device -- no network streaming is taking place. The videos contain audio tracks. I'm working on an iOS application that requires playing video files with minimum delay to start the video clip in question. Unfortunately we do not know what specific video clip is next until we actually need to start it up. Specifically: When one video clip is playing, we will know what the next set of (roughly) 10 video clips are, but we don't know which one exactly, until it comes time to 'immediately' play the next clip. What I've done to look at actual start delays is to call addBoundaryTimeObserverForTimes on the video player, with a time period of one millisecond to see when the video actually started to play, and I take the difference of that time stamp with the first place in the code that indicates which asset to start playing. From what I've seen thus-far, I have found that using the combination of AVAsset loading, and then creating an AVPlayerItem from that once it's ready, and then waiting for AVPlayerStatusReadyToPlay before I call play, tends to take between 1 and 3 seconds to start the clip. I've since switched to what I think is roughly equivalent: calling [AVPlayerItem playerItemWithURL:] and waiting for AVPlayerItemStatusReadyToPlay to play. Roughly same performance. One thing I'm observing is that the first AVPlayer item load is slower than the rest. Seems one idea is to pre-flight the AVPlayer with a short / empty asset before trying to play the first video might be of good general practice. [http://stackoverflow.com/questions/900461/slow-start-for-avaudioplayer-the-first-time-a-sound-is-played] I'd love to get the video start times down as much as possible, and have some ideas of things to experiment with, but would like some guidance from anyone that might be able to help. Update: idea 7, below, as-implemented yields switching times of around 500 ms. This is an improvement, but it it'd be nice to get this even faster. Idea 1: Use N AVPlayers (won't work) Using ~ 10 AVPPlayer objects and start-and-pause all ~ 10 clips, and once we know which one we really need, switch to, and un-pause the correct AVPlayer, and start all over again for the next cycle. I don't think this works, because I've read there is roughly a limit of 4 active AVPlayer's in iOS. There was someone asking about this on StackOverflow here, and found out about the 4 AVPlayer limit: fast-switching-between-videos-using-avfoundation Idea 2: Use AVQueuePlayer (won't work) I don't believe that shoving 10 AVPlayerItems into an AVQueuePlayer would pre-load them all for seamless start. AVQueuePlayer is a queue, and I think it really only makes the next video in the queue ready for immediate playback. I don't know which one out of ~10 videos we do want to play back, until it's time to start that one. ios-avplayer-video-preloading Idea 3: Load, Play, and retain AVPlayerItems in background (not 100% sure yet -- but not looking good) I'm looking at if there is any benefit to load and play the first second of each video clip in the background (suppress video and audio output), and keep a reference to each AVPlayerItem, and when we know which item needs to be played for real, swap that one in, and swap the background AVPlayer with the active one. Rinse and Repeat. The theory would be that recently played AVPlayer/AVPlayerItem's may still hold some prepared resources which would make subsequent playback faster. So far, I have not seen benefits from this, but I might not have the AVPlayerLayer setup correctly for the background. I doubt this will really improve things from what I've seen. Idea 4: Use a different file format -- maybe one that is faster to load? I'm currently using .m4v's (video-MPEG4) H.264 format. I have not played around with other formats, but it may well be that some formats are faster to decode / get ready than others. Possible still using video-MPEG4 but with a different codec, or maybe quicktime? Maybe a lossless video format where decoding / setup is faster? Idea 5: Combination of lossless video format + AVQueuePlayer If there is a video format that is fast to load, but maybe where the file size is insane, one idea might be to pre-prepare the first 10 seconds of each video clip with a version that is boated but faster to load, but back that up with an asset that is encoded in H.264. Use an AVQueuePlayer, and add the first 10 seconds in the uncompressed file format, and follow that up with one that is in H.264 which gets up to 10 seconds of prepare/preload time. So I'd get 'the best' of both worlds: fast start times, but also benefits from a more compact format. Idea 6: Use a non-standard AVPlayer / write my own / use someone else's Given my needs, maybe I can't use AVPlayer, but have to resort to AVAssetReader, and decode the first few seconds (possibly write raw file to disk), and when it comes to playback, make use of the raw format to play it back fast. Seems like a huge project to me, and if I go about it in a naive way, it's unclear / unlikely to even work better. Each decoded and uncompressed video frame is 2.25 MB. Naively speaking -- if we go with ~ 30 fps for the video, I'd end up with ~60 MB/s read-from-disk requirement, which is probably impossible / pushing it. Obviously we'd have to do some level of image compression (perhaps native openGL/es compression formats via PVRTC)... but that's kind crazy. Maybe there is a library out there that I can use? Idea 7: Combine everything into a single movie asset, and seekToTime One idea that might be easier than some of the above, is to combine everything into a single movie, and use seekToTime. The thing is that we'd be jumping all around the place. Essentially random access into the movie. I think this may actually work out okay: avplayer-movie-playing-lag-in-ios5 Which approach do you think would be best? So far, I've not made that much progress in terms of reducing the lag.

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  • how to reduce 2d array

    - by owca
    I have a 2d array, let's say like this : 2 0 8 9 3 0 -1 20 13 12 17 18 1 2 3 4 2 0 7 9 How to create an array reduced by let's say 2nd row and third column? 2 0 9 13 12 18 1 2 4 2 0 9

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  • Reduce lines of code

    - by coffeeaddict
    I'm not a JavaScript guru (yet). I am trying to figure out a way to cut down the number of lines below...are there any shortcuts for lets say the if statements? function showDialog(divID) { var dialogDiv = $("#" + divID); var height = 500; var width = 400; var resizable = false; if (dialogDiv.attr("height") != "") { height = parseInt(dialogDiv.attr("height")); } if (dialogDiv.attr("width") != "") { width = parseInt(dialogDiv.attr("width")); } if (dialogDiv.attr("resizable") != "") { resizable = dialogDiv.attr("resizable"); } dialogDiv.dialog ( { resizable: resizable, width: width, height: height, bgiframe: true, modal: true, autoOpen: false, show: 'blind' } ) dialogDiv.dialog("open"); }

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  • Reduce number of config files to as few as possible

    - by Scott
    For most of my applications I use iBatis.Net for database access/modeling and log4Net for logging. In doing this, I need a number of *.config files for each project. For example, for a simple application I need to have the following *.config files: app.config ([AssemblyName].[Extention].config) [AssemblyName].SqlMap.config [AssemblyName].log4Net.config [AssemblyName].SqlMapProperties.config providers.config When these applications go from DEV to TEST to PRODUCTION environments, the settings contained in these files change depending on the environment. When the number of files get compounded by having 5-10 (or more) supporting executables per project, the work load on the infrastructure team (the ones doing the roll-outs to the different environments) gets rather high. We also have a high risk of one of the config files being missed, or a mistype in the config file. What is the best way to avoid these risks? Should I combine all of the config files into one file? (is that possible with iBatis?) I know that with VisualStudio 2010 they introduce transforms for these config files that allow the developer to setup all the settings for the different environments and then dynamically (depending on the build kicked off) the config files get updated to the correct versions. (VS 2010 - transforms) Thank you for any help that you can provide.

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  • Reduce Multiple Errors logging in sysssislog

    - by Akshay
    Need help. I am trying to automate error notifications to be sent in mailers. For that I am querying the sysssislog table. I have pasted an "Execute SQl task" on the package event handler "On error". For testing purpose, I am deliberately trying to load duplicate keys in a table which consists of a Primary key column(so as to get an error). But instead of having just one error, "Violation of primary key constraint", SSIS records 3 in the table. PFA the screenshot as well. How can i restrict the tool to log only one error and not multiple ??? Package Structure. Package ("On error Event handler") - DFT - Oledb Source - Oledb Destination SSIS Error Code DTS_E_OLEDBERROR. An OLE DB error has occurred. Error code: 0x80004005. An OLE DB record is available. Source: "Microsoft SQL Server Native Client 10.0" Hresult: 0x80004005 Description: "The statement has been terminated.". An OLE DB record is available. Source: "Microsoft SQL Server Native Client 10.0" Hresult: 0x80004005 Description: "Violation of PRIMARY KEY constraint 'PK_SalesPerson_SalesPersonID'. Cannot insert duplicate key in object 'dbo.SalesPerson'.". SSIS Error Code DTS_E_INDUCEDTRANSFORMFAILUREONERROR. The "input "OLE DB Destination Input" (56)" failed because error code 0xC020907B occurred, and the error row disposition on "input "OLE DB Destination Input" (56)" specifies failure on error. An error occurred on the specified object of the specified component. There may be error messages posted before this with more information about the failure. SSIS Error Code DTS_E_PROCESSINPUTFAILED. The ProcessInput method on component "OLE DB Destination" (43) failed with error code 0xC0209029 while processing input "OLE DB Destination Input" (56). The identified component returned an error from the ProcessInput method. The error is specific to the component, but the error is fatal and will cause the Data Flow task to stop running. There may be error messages posted before this with more information about the failure. Please guide me. Your help is very much appreciated. Thanks

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  • How to reduce compilation times with Boost Asio

    - by Artyom
    Boost.Asio is great library but it has one huge drawback -- extreamly slow compilation times. A simple implementation (really simple) of HTTP protocol (about 1k lines of code) requires about 13.5s to compile under GCC 4.4! I tryed to use PCH but it does not improve compilation times too much (about 1s. only). So are there any tutorials on how to make Boost.Asio compilation times faster? For example what headers should I exactly include for what class. I use for example: io_service, tcp::ip::sockets, tcp::ip::acceptor, deadline_timer, buffers and few functions like async_read, async_write. Any suggestions? P.S.: I do use pimpl whenever I can.

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  • kick off a map reduce job from my java/mysql webapp

    - by Brian
    Hi guys, I need a bit of archecture advice. I have a java based webapp, with a JPA based ORM backed onto a mysql relational database. Now, as part of the application I have a batch job that compares thousands of database records with each other. This job has become too time consuming and needs to be parallelized. I'm looking at using mapreduce and hadoop in order to do this. However, I'm not too sure about how to integrate this into my current architecture. I think the easiest initial solution is to find a way to push data from mysql into hadoop jobs. I have done some initial research on this and found the following relevant information and possibilities: 1) https://issues.apache.org/jira/browse/HADOOP-2536 this gives an interesting overview of some inbuilt JDBC support 2) This article http://architects.dzone.com/articles/tools-moving-sql-database describes some third party tools to move data from mysql to hadoop. To be honest I'm just starting out with learning about hbase and hadoop but I really don't know how to integrate this into my webapp. Any advice is greatly appreciated. cheers, Brian

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  • JavaScript Metaprogramming: Reduce boilerplate of adding functions to a function queue

    - by thurn
    I'm working with animation in JavaScript, and I have a bunch of functions you can call to add things to the animation queue. Basically, all of these functions look like this: function foo(arg1, arg2) { _eventQueue.push(function() { // actual logic } } I'm wondering now if it would be possible to cut down on this boilerplate a little bit, though, so I don't need that extra "_eventQueue" line in the function body dozens of times. Would it be possible, for example, to make a helper function which takes an arbitrary function as an argument and returns a new function which is augmented to be automatically added to the event queue? The only problem is that I need to find a way to maintain access to the function's original arguments in this process, which is... complicated.

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  • Visual Studio 2010 -- how to reduce its memory footprint

    - by GregC
    I have a solution with just under 100 projects in it, a mix of C++ and C# (mostly C#). When working in VS2005, the working set of Visual Studio is considerably smaller than that of VS2010. I was wondering if there are some things that can be turned off, so I can develop in VS2010 under 32-bit OS without running out of memory.

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  • How can I reduce jQuery?

    - by Tommy
    I'm using just a few basic jQuery functions on my site. How can I remove unused jQuery code? Knowing only the basics, I looked at the code and was not sure where to start. If you could point me in the right direction, that would be appreciated. Thanks.

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  • Optimizing tasks to reduce CPU in a trading application

    - by Joel
    Hello, I have designed a trading application that handles customers stocks investment portfolio. I am using two datastore kinds: Stocks - Contains unique stock name and its daily percent change. UserTransactions - Contains information regarding a specific purchase of a stock made by a user : the value of the purchase along with a reference to Stock for the current purchase. db.Model python modules: class Stocks (db.Model): stockname = db.StringProperty(multiline=True) dailyPercentChange=db.FloatProperty(default=1.0) class UserTransactions (db.Model): buyer = db.UserProperty() value=db.FloatProperty() stockref = db.ReferenceProperty(Stocks) Once an hour I need to update the database: update the daily percent change in Stocks and then update the value of all entities in UserTransactions that refer to that stock. The following python module iterates over all the stocks, update the dailyPercentChange property, and invoke a task to go over all UserTransactions entities which refer to the stock and update their value: Stocks.py # Iterate over all stocks in datastore for stock in Stocks.all(): # update daily percent change in datastore db.run_in_transaction(updateStockTxn, stock.key()) # create a task to update all user transactions entities referring to this stock taskqueue.add(url='/task', params={'stock_key': str(stock.key(), 'value' : self.request.get ('some_val_for_stock') }) def updateStockTxn(stock_key): #fetch the stock again - necessary to avoid concurrency updates stock = db.get(stock_key) stock.dailyPercentChange= data.get('some_val_for_stock') # I get this value from outside ... some more calculations here ... stock.put() Task.py (/task) # Amount of transaction per task amountPerCall=10 stock=db.get(self.request.get("stock_key")) # Get all user transactions which point to current stock user_transaction_query=stock.usertransactions_set cursor=self.request.get("cursor") if cursor: user_transaction_query.with_cursor(cursor) # Spawn another task if more than 10 transactions are in datastore transactions = user_transaction_query.fetch(amountPerCall) if len(transactions)==amountPerCall: taskqueue.add(url='/task', params={'stock_key': str(stock.key(), 'value' : self.request.get ('some_val_for_stock'), 'cursor': user_transaction_query.cursor() }) # Iterate over all transaction pointing to stock and update their value for transaction in transactions: db.run_in_transaction(updateUserTransactionTxn, transaction.key()) def updateUserTransactionTxn(transaction_key): #fetch the transaction again - necessary to avoid concurrency updates transaction = db.get(transaction_key) transaction.value= transaction.value* self.request.get ('some_val_for_stock') db.put(transaction) The problem: Currently the system works great, but the problem is that it is not scaling well… I have around 100 Stocks with 300 User Transactions, and I run the update every hour. In the dashboard, I see that the task.py takes around 65% of the CPU (Stock.py takes around 20%-30%) and I am using almost all of the 6.5 free CPU hours given to me by app engine. I have no problem to enable billing and pay for additional CPU, but the problem is the scaling of the system… Using 6.5 CPU hours for 100 stocks is very poor. I was wondering, given the requirements of the system as mentioned above, if there is a better and more efficient implementation (or just a small change that can help with the current implemntation) than the one presented here. Thanks!! Joel

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  • How to reduce java concurrent mode failure and excessive gc

    - by jimx
    In Java, the concurrent mode failure means that the concurrent collector failed to free up enough memory space form tenured and permanent gen and has to give up and let the full stop-the-world gc kicks in. The end result could be very expensive. I understand this concept but never had a good comprehensive understanding of A) what could cause a concurrent mode failure and B) what's the solution?. This sort of unclearness leads me to write/debug code without much of hints in mind and often has to shop around those performance flags from Foo to Bar without particular reasons, just have to try. I'd like to learn from developers here how your experience is. If you had previous encountered such performance issue, what was the cause and how you addressed it? If you have coding recommendations, please don't be too general. Thanks!

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  • Trying to reduce the speed overhead of an almost-but-not-quite-int number class

    - by Fumiyo Eda
    I have implemented a C++ class which behaves very similarly to the standard int type. The difference is that it has an additional concept of "epsilon" which represents some tiny value that is much less than 1, but greater than 0. One way to think of it is as a very wide fixed point number with 32 MSBs (the integer parts), 32 LSBs (the epsilon parts) and a huge sea of zeros in between. The following class works, but introduces a ~2x speed penalty in the overall program. (The program includes code that has nothing to do with this class, so the actual speed penalty of this class is probably much greater than 2x.) I can't paste the code that is using this class, but I can say the following: +, -, +=, <, > and >= are the only heavily used operators. Use of setEpsilon() and getInt() is extremely rare. * is also rare, and does not even need to consider the epsilon values at all. Here is the class: #include <limits> struct int32Uepsilon { typedef int32Uepsilon Self; int32Uepsilon () { _value = 0; _eps = 0; } int32Uepsilon (const int &i) { _value = i; _eps = 0; } void setEpsilon() { _eps = 1; } Self operator+(const Self &rhs) const { Self result = *this; result._value += rhs._value; result._eps += rhs._eps; return result; } Self operator-(const Self &rhs) const { Self result = *this; result._value -= rhs._value; result._eps -= rhs._eps; return result; } Self operator-( ) const { Self result = *this; result._value = -result._value; result._eps = -result._eps; return result; } Self operator*(const Self &rhs) const { return this->getInt() * rhs.getInt(); } // XXX: discards epsilon bool operator<(const Self &rhs) const { return (_value < rhs._value) || (_value == rhs._value && _eps < rhs._eps); } bool operator>(const Self &rhs) const { return (_value > rhs._value) || (_value == rhs._value && _eps > rhs._eps); } bool operator>=(const Self &rhs) const { return (_value >= rhs._value) || (_value == rhs._value && _eps >= rhs._eps); } Self &operator+=(const Self &rhs) { this->_value += rhs._value; this->_eps += rhs._eps; return *this; } Self &operator-=(const Self &rhs) { this->_value -= rhs._value; this->_eps -= rhs._eps; return *this; } int getInt() const { return(_value); } private: int _value; int _eps; }; namespace std { template<> struct numeric_limits<int32Uepsilon> { static const bool is_signed = true; static int max() { return 2147483647; } } }; The code above works, but it is quite slow. Does anyone have any ideas on how to improve performance? There are a few hints/details I can give that might be helpful: 32 bits are definitely insufficient to hold both _value and _eps. In practice, up to 24 ~ 28 bits of _value are used and up to 20 bits of _eps are used. I could not measure a significant performance difference between using int32_t and int64_t, so memory overhead itself is probably not the problem here. Saturating addition/subtraction on _eps would be cool, but isn't really necessary. Note that the signs of _value and _eps are not necessarily the same! This broke my first attempt at speeding this class up. Inline assembly is no problem, so long as it works with GCC on a Core i7 system running Linux!

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  • How to reduce the need for IISRESET for developing ASP.NET web app in IIS 5.1

    - by John Galt
    I have a web application project on my dev PC running WinXP and hence IIS 5.1. The changes I'm making to this site seem to "take effect" only after I do IISRESET. That is, I make a source change, Rebuild the project and then Start without Debugging (or with debugging). The newly changed code is not "visible" or in effect unless I intervene with an IISRESET. BTW, the "web" tab on the Properties display for the web app project is configured to use the Local IIS web server at project Url: http://localhost/myVirtualDirectory ... but I've noticed the same issue when using the VStudio Dev Server (i.e. I have to stop it by visiting the taskbar tray area in order to see my source changes take effect). Is this something I can change? EDIT UPDATE: Just wanting to clear this up if possible. Two answers diverge below; not sure how to move forward. One states this is to be expected (weakness of IIS 5.1 which in turn is the best WinXP can provide). Another states this is not expected behavior (and I tend to agree since this is the first I've encounted this on the same old WinXP dev platform I've had a long time). I suspect it may be something "deep inside" the Visual Studio 2008 web app which was upgraded to this new IDE from VStudio 2002 (ASP.NET 1.1). I've tried to add comment/questions down each answer path. Thanks.

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