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  • ASP.NET High CPU Bringing Servers to their Knees

    - by user880954
    Ok, our new build is having 100% cpu spikes on each server at random intervals. For long durations it make the site totally unresponsive - this will be at peak times as people in different countries log on to the site etc. We've looked at perfmom, memory profilers, CLR profiler, sql profilers, Red gate ants profiler, tried load testing in UAT - but cannot even reproduce the problem. This could mean only thousands of users hitting the live site causes it to happen. One pattern we did notice was that the new code - the broken build - actually uses noticably less threads. We are also using spring for IOC - does this have a bed reputation? To make things worse, we cannot deploy to live due to the business impact - so cannot narrow the problem down to subset of the new features we've added. We truly are destroyed - has anyone got any battle scars that may save us a few lives?

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  • Should we denormalize database to improve performance?

    - by Groo
    We have a requirement to store 500 measurements per second, coming from several devices. Each measurement consists of a timestamp, a quantity type, and several vector values. Right now there is 8 vector values per measurement, and we may consider this number to be constant for needs of our prototype project. We are using HNibernate. Tests are done in SQLite (disk file db, not in-memory), but production will probably be MsSQL. Our Measurement entity class is the one that holds a single measurement, and looks like this: public class Measurement { public virtual Guid Id { get; private set; } public virtual Device Device { get; private set; } public virtual Timestamp Timestamp { get; private set; } public virtual IList<VectorValue> Vectors { get; private set; } } Vector values are stored in a separate table, so that each of them references its parent measurement through a foreign key. We have done a couple of things to ensure that generated SQL is (reasonably) efficient: we are using Guid.Comb for generating IDs, we are flushing around 500 items in a single transaction, ADO.Net batch size is set to 100 (I think SQLIte does not support batch updates? But it might be useful later). The problem Right now we can insert 150-200 measurements per second (which is not fast enough, although this is SQLite we are talking about). Looking at the generated SQL, we can see that in a single transaction we insert (as expected): 1 timestamp 1 measurement 8 vector values which means that we are actually doing 10x more single table inserts: 1500-2000 per second. If we placed everything (all 8 vector values and the timestamp) into the measurement table (adding 9 dedicated columns), it seems that we could increase our insert speed up to 10 times. Switching to SQL server will improve performance, but we would like to know if there might be a way to avoid unnecessary performance costs related to the way database is organized right now. [Edit] With in-memory SQLite I get around 350 items/sec (3500 single table inserts), which I believe is about as good as it gets with NHibernate (taking this post for reference: http://ayende.com/Blog/archive/2009/08/22/nhibernate-perf-tricks.aspx). But I might as well switch to SQL server and stop assuming things, right? I will update my post as soon as I test it.

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  • DataView Vs DataTable.Select()

    - by Aseem Gautam
    Considering the code below: Dataview someView = new DataView(sometable) someView.RowFilter = someFilter; if(someView.count > 0) { …. } Quite a number of articles which say Datatable.Select() is better than using DataViews, but these are prior to VS2008. Solved: The Mystery of DataView's Poor Performance with Large Recordsets Array of DataRecord vs. DataView: A Dramatic Difference in Performance So in a situation where I just want a subset of datarows based on some filter criteria(single query) and what is better DataView or DataTable.Select()?

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  • Performance tuning of a Hibernate+Spring+MySQL project operation that stores images uploaded by user

    - by Umar
    Hi I am working on a web project that is Spring+Hibernate+MySQL based. I am stuck at a point where I have to store images uploaded by a user into the database. Although I have written some code that works well for now, but I believe that things will mess up when the project would go live. Here's my domain class that carries the image bytes: @Entity public class Picture implements java.io.Serializable{ long id; byte[] data; ... // getters and setters } And here's my controller that saves the file on submit: public class PictureUploadFormController extends AbstractBaseFormController{ ... protected ModelAndView onSubmit(HttpServletRequest request, HttpServletResponse response, Object command, BindException errors) throws Exception{ MutlipartFile file; // getting MultipartFile from the command object ... // beginning hibernate transaction ... Picture p=new Picture(); p.setData(file.getBytes()); pictureDAO.makePersistent(p); // this method simply calls getSession().saveOrUpdate(p) // committing hiernate transaction ... } ... } Obviously a bad piece of code. Is there anyway I could use InputStream or Blob to save the data, instead of first loading all the bytes from the user into the memory and then pushing them into the database? I did some research on hibernate's support for Blob, and found this in Hibernate In Action book: java.sql.Blob and java.sql.Clob are the most efficient way to handle large objects in Java. Unfortunately, an instance of Blob or Clob is only useable until the JDBC transaction completes. So if your persistent class defines a property of java.sql.Clob or java.sql.Blob (not a good idea anyway), you’ll be restricted in how instances of the class may be used. In particular, you won’t be able to use instances of that class as detached objects. Furthermore, many JDBC drivers don’t feature working support for java.sql.Blob and java.sql.Clob. Therefore, it makes more sense to map large objects using the binary or text mapping type, assuming retrieval of the entire large object into memory isn’t a performance killer. Note you can find up-to-date design patterns and tips for large object usage on the Hibernate website, with tricks for particular platforms. Now apparently the Blob cannot be used, as it is not a good idea anyway, what else could be used to improve the performance? I couldn't find any up-to-date design pattern or any useful information on Hibernate website. So any help/recommendations from stackoverflowers will be much appreciated. Thanks

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  • Index on column with only 2 distinct values

    - by Will
    I am wondering about the performance of this index: I have an "Invalid" varchar(1) column that has 2 values: NULL or 'Y' I have an index on (invalid), as well as (invalid, last_validated) Last_validated is a datetime (this is used for a unrelated SELECT query) I am flagging a small amount of items (1-5%) of rows in the table with this as 'to be deleted'. This is so when i DELETE FROM items WHERE invalid='Y' it does not perform a full table scan for the invalid items. A problem seems to be, the actual DELETE is quite slow now, possibly because all the indexes are being removed as they are deleted. Would a bitmap index provide better performance for this? or perhaps no index at all?

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  • Java - Collections.sort() performance

    - by msr
    Hello, Im using Collections.sort() to sort a LinkedList whose elements implements Comparable interface, so they are sorted in a natural order. In the javadoc documentation its said this method uses mergesort algorithm wich has n*log(n) performance. My question is if there is a more efficient algorithm to sort my LinkedList? The size of that list could be very high and sort will be also very frequent. Thanks!

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  • Caching Mysql database for better performance

    - by kobey
    Hi, I'm using Amazon cloud and I've performance issue since the HDD is not located on my machine. My database is small (~500MB) and I can afford to keep it all in my RAM. I do not want to keep queries in my RAM, i need all the tables there. How can i do it? Thanks, Koby P.S. I'm using ubuntu server...

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  • My KDE very slow in certain operations

    - by Pietro
    I have a problem with my Linux installation. It seems that the KDE code that deals with directory windows is extremely slow (on both Dolphin and Konqueror). This happens both when I click on a directory icon and when I want to open/save a file from many KDE applications. The time the window takes to open can be one minute or more. The same happens when I right click on an icon. Looking at the CPU usage, this is very low (less than 10%). Am I the only one with this problem, or is it well known and maybe already fixed? Consider that I cannot update to a more recent version of OpenSuse. Thank you, Pietro Configuration: Linux version: OpenSuse 11.4 KDE 4.6.0 System: DELL Precision T3500 - Intel Xeon Home directory mounted on a remote drive. <-- could this be the reason?

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  • How do you code up a pattern matching code block in scala?

    - by egervari
    How do you code a function that takes in a block of code as a parameter that contains case statements? For instance, in my block of code, I don't want to do a match or a default case explicitly. I am looking something like this myApi { case Whatever() => // code for case 1 case SomethingElse() => // code for case 2 } And inside of my myApi(), it'll actually execute the code block and do the matches. Help?

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  • Are bit operations quick?

    - by flashnik
    I'm dealing with a problem which needs to work with a lot of data. Currently its' values are represented as unsigned int. I know that real values do not exceed some limit, say 1000. That means that I can use unsigned short to store it. One profit is that it'll use less space. Do I have to pay for it by loosing in performance? Another assumption. I decided to store data as short but all calling functions use int, so I need to convert between these datatypes when storing/extracting values. Wiil the performance lost be dramatic? Third assumption. Due to great wish to econom memory I decided to use not short but just 10 bits packed into array of unsigned int. What will happen in this case comparing with previous ones?

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  • Lack of ImageList in MenuStrip and performance issues

    - by Ivan
    MenuStrip doesn't support using ImageList images. What are performance issues of this? Are there chances of using too much GDI resources and slow-downs? How many items should be considered acceptable, after which one should implement custom control that draws images from ImageList?

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  • Is there some performance issue between leaving empty ListProperties or using dynamic (expando) prop

    - by indiehacker
    Is there a datastore performance difference between adding dynamic properties of the expando class when they are needed for an entity or the simpler (for me) framework of just setting up all possible properties I might need from the start even though most instances will just be left empty. In my specific case I would be having 5-8 empty ReferenceList properties as 'overhead' that will be empty when I skip using expando class.

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  • beneficial in terms of performance

    - by Usama Khalil
    Hi, is it better to declare Webservice class object instances as static as the .asmx webservice classes have only static methods. what i want is that i declare and instantiate webservice asmx class as static in aspx Page Behind Class. and on every event call on that page i could perform operation against webservice methods. is it beneficial in terms of performance? Thanks Usama

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  • How does MySQL 5.5 and InnoDB on Linux use RAM?

    - by Loren
    Does MySQL 5.5 InnoDB keep indexes in memory and tables on disk? Does it ever do it's own in-memory caching of part or whole tables? Or does it completely rely on the OS page cache (I'm guessing that it does since Facebook's SSD cache that was built for MySQL was done at the OS-level: https://github.com/facebook/flashcache/)? Does Linux by default use all of the available RAM for the page cache? So if RAM size exceeds table size + memory used by processes, then when MySQL server starts and reads the whole table for the first time it will be from disk, and from that point on the whole table is in RAM? So using Alchemy Database (SQL on top of Redis, everything always in RAM: http://code.google.com/p/alchemydatabase/) shouldn't be much faster than MySQL, given the same size RAM and database?

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  • Does Google Analytics have peformance overhead?

    - by Mohit Nanda
    To what extent does Google Analytics impact performance? I'm looking for the following: Benchmarks (including response times/pageload times et al) Links or results to similar benchmarks One (possible) method of testing Google Analytics (GA) on your site: Serve ga.js (the Google Analytics JavaScript file) from your own server. Update from Google Daily (test 1) and Weekly (test 2). I would be interested to see how this reduces the communication between the client webserver and the GA server. Has anyone conducted any of these tests? If so, can you provide your results? If not, does anyone have a better method for testing the performance hit (or lack thereof) for using GA?

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  • Choking experienced while using the TCP/IP Adapter for BizTalk Server 2006

    - by Burhan
    I am using the TCP/IP Adapter for BizTalk Server 2006 which was obtained from codeplex: http://www.codeplex.com/BTSTCPIP Once the application was deployed in production, we started to experience choking in the performance of the application. The more the requests, the more the performance degradation. Sometimes, it happens that the receive ports become non-responsive and we have to forcefully restart the host instances to temporarily let the services respond again but we experience the same problems again and again. I would like to ask if any of you have used the same adapter and have you ever experienced the similar issues? If yes, how can we overcome theses issues. Thanks.

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  • LINQ entity query performance

    - by Abdel Olakara
    Hi all, I have a silly question. I would like to know if there is performance deference in these two quries: var cObject = from cust in entities.Customer where cust.id == cid select cust; and var cObject = entities.Customer.First( c=> c.id == cid); My query return only one record as I am querying with the primary key. But do they make any difference?

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  • Code First / Database First / Model First : are they just personnal preferences?

    - by Antoine M
    Merely knowing the internal functionality of each approaches, and after reading a lot of posts, I still can't figure out if each one of them is just a matter of personnal preference for the developper or if they deserve different axes of productivity ? Does one of them should be applyed for some specific productivity needs or MS is just beeing kind offering three different flavours ? Should we consider CF as a sort of improvement over DBF or MF and thinking of it as a futur standard on wich spending a peculiar intelectual investment ... ? Is there a link showing a sort of synthetic table with un-passionate pros and cons for each approach, a little bit like for web-forms and MVC. Sorry for those who will find this question redondant. I know it is.

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  • How a JIT compiler helps performance of applications?

    - by igorgue
    I just read that Android has a 450% performance improvement because it added a JIT compiler, I know what JIT is, but I don't really understand why is it faster than normal compiled code? or what's the difference with the older approach from the Android platform (the Java like run compiled bytecode). Thanks!

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  • Array performance question

    - by Konrad
    I am very familiar with STL vector (and other container) performance guarantees, however I can't seem to find anything concrete about plain arrays. Are pointer arithmetic and [] methods constant or linear time?

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  • Sql query: use where in or foreach?

    - by phenevo
    Hi, I'm using query, where the piece is: ...where code in ('va1','var2'...') I have about 50k of this codes. It was working when I has 30k codes, but know I get: The query processor ran out of internal resources and could not produce a query plan. This is a rare event and only expected for extremely complex queries or queries that reference a very large number of tables or partition I think that problem is related with IN... So now I'm planning use foreach(string code in codes) ...where code =code Is it good Idea ??

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  • [CODE GENERATION] How to generate DELETE statements in PL/SQL, based on the tables FK relations?

    - by The chicken in the kitchen
    Is it possible via script/tool to generate authomatically many delete statements based on the tables fk relations, using Oracle PL/SQL? In example: I have the table: CHICKEN (CHICKEN_CODE NUMBER) and there are 30 tables with fk references to its CHICKEN_CODE that I need to delete; there are also other 150 tables foreign-key-linked to that 30 tables that I need to delete first. Is there some tool/script PL/SQL that I can run in order to generate all the necessary delete statements based on the FK relations for me? (by the way, I know about cascade delete on the relations, but please pay attention: I CAN'T USE IT IN MY PRODUCTION DATABASE, because it's dangerous!) I'm using Oracle DataBase 10G R2. This is the result I've written, but it is not recursive: This is a view I have previously written, but of course it is not recursive! CREATE OR REPLACE FORCE VIEW RUN ( OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME, VINCOLO ) AS SELECT OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME, '(' || LTRIM ( EXTRACT (XMLAGG (XMLELEMENT ("x", ',' || COLUMN_NAME)), '/x/text()'), ',') || ')' VINCOLO FROM ( SELECT CON1.OWNER OWNER_1, CON1.TABLE_NAME TABLE_NAME_1, CON1.CONSTRAINT_NAME CONSTRAINT_NAME_1, CON1.DELETE_RULE, CON1.STATUS, CON.TABLE_NAME, CON.CONSTRAINT_NAME, COL.POSITION, COL.COLUMN_NAME FROM DBA_CONSTRAINTS CON, DBA_CONS_COLUMNS COL, DBA_CONSTRAINTS CON1 WHERE CON.OWNER = 'TABLE_OWNER' AND CON.TABLE_NAME = 'TABLE_OWNED' AND ( (CON.CONSTRAINT_TYPE = 'P') OR (CON.CONSTRAINT_TYPE = 'U')) AND COL.TABLE_NAME = CON1.TABLE_NAME AND COL.CONSTRAINT_NAME = CON1.CONSTRAINT_NAME --AND CON1.OWNER = CON.OWNER AND CON1.R_CONSTRAINT_NAME = CON.CONSTRAINT_NAME AND CON1.CONSTRAINT_TYPE = 'R' GROUP BY CON1.OWNER, CON1.TABLE_NAME, CON1.CONSTRAINT_NAME, CON1.DELETE_RULE, CON1.STATUS, CON.TABLE_NAME, CON.CONSTRAINT_NAME, COL.POSITION, COL.COLUMN_NAME) GROUP BY OWNER_1, CONSTRAINT_NAME_1, TABLE_NAME_1, TABLE_NAME; ... and it contains the error of using DBA_CONSTRAINTS instead of ALL_CONSTRAINTS...

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