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  • android app does not show up on my device or the emulator in eclipse

    - by Sam
    hey everyone, I have no errors in my app-code what so ever, but when i try to run in on either my cell or my emulator/the avd in eclipse i can't run it because it doesn't show up on either one. this is my console output: [2011-02-04 08:14:58 - Versuch] Uploading Versuch.apk onto device 'CB511L2WTB' [2011-02-04 08:14:58 - Versuch] Installing Versuch.apk... [2011-02-04 08:15:01 - Versuch] Success! [2011-02-04 08:15:01 - Versuch] \Versuch\bin\Versuch.apk installed on device [2011-02-04 08:15:01 - Versuch] Done! and this is my LogCat output, which tells me nothing, but you are the experts ;) 02-04 08:18:10.020: DEBUG/dalvikvm(22167): GC freed 2576 objects / 559120 bytes in 37ms 02-04 08:18:10.700: DEBUG/dalvikvm(6709): GC freed 7692 objects / 478912 bytes in 41ms 02-04 08:18:11.170: DEBUG/dalvikvm(31774): GC freed 3367 objects / 163464 bytes in 122ms 02-04 08:18:13.230: DEBUG/dalvikvm(22167): GC freed 2790 objects / 552328 bytes in 38ms 02-04 08:18:14.650: DEBUG/dalvikvm(6709): GC freed 8443 objects / 540440 bytes in 39ms 02-04 08:18:16.260: DEBUG/dalvikvm(31921): GC freed 214 objects / 9824 bytes in 216ms 02-04 08:18:16.670: DEBUG/dalvikvm(22167): GC freed 3232 objects / 561256 bytes in 40ms 02-04 08:18:18.600: DEBUG/dalvikvm(6709): GC freed 7718 objects / 481952 bytes in 39ms 02-04 08:18:19.210: DEBUG/dalvikvm(1129): GC freed 6898 objects / 275328 bytes in 109ms 02-04 08:18:19.690: DEBUG/dalvikvm(22167): GC freed 2968 objects / 571232 bytes in 39ms 02-04 08:18:21.440: DEBUG/dalvikvm(1212): GC freed 1020 objects / 49328 bytes in 395ms 02-04 08:18:22.570: DEBUG/dalvikvm(6709): GC freed 7893 objects / 495616 bytes in 40ms 02-04 08:18:23.060: DEBUG/dalvikvm(22167): GC freed 3117 objects / 561912 bytes in 41ms 02-04 08:18:25.860: DEBUG/dalvikvm(22167): GC freed 2924 objects / 558448 bytes in 36ms 02-04 08:18:26.350: DEBUG/dalvikvm(32098): GC freed 4662 objects / 495496 bytes in 290ms 02-04 08:18:26.410: DEBUG/dalvikvm(22167): GC freed 1077 objects / 130680 bytes in 33ms 02-04 08:18:27.080: DEBUG/dalvikvm(6709): GC freed 7912 objects / 485368 bytes in 40ms 02-04 08:18:28.190: DEBUG/dalvikvm(22167): GC freed 953 objects / 767272 bytes in 33ms 02-04 08:18:29.500: DEBUG/dalvikvm(1129): GC freed 6756 objects / 270480 bytes in 105ms 02-04 08:18:30.500: WARN/System.err(22536): java.lang.Exception: You must call com.mercuryintermedia.productconfiguration.initialize() first 02-04 08:18:30.670: WARN/System.err(22536): at com.mercuryintermedia.ProductConfiguration.getProductName(ProductConfiguration.java:136) 02-04 08:18:30.670: WARN/System.err(22536): at com.mercuryintermedia.api.rest.Item.getPublishingContainersItems(Item.java:15) 02-04 08:18:30.670: WARN/System.err(22536): at com.mercuryintermedia.mflow.ContainerHelper.getContainerFromServer(ContainerHelper.java:68) 02-04 08:18:30.670: WARN/System.err(22536): at com.mercuryintermedia.mflow.ContainerHelper.run(ContainerHelper.java:46) 02-04 08:18:31.090: DEBUG/dalvikvm(6709): GC freed 10545 objects / 682480 bytes in 49ms 02-04 08:18:31.120: DEBUG/dalvikvm(1813): GC freed 5970 objects / 310912 bytes in 60ms 02-04 08:18:31.320: DEBUG/dalvikvm(22167): GC freed 2468 objects / 539520 bytes in 39ms 02-04 08:18:34.110: DEBUG/dalvikvm(22167): GC freed 2879 objects / 569008 bytes in 35ms 02-04 08:18:34.920: DEBUG/dalvikvm(6709): GC freed 7029 objects / 424632 bytes in 35ms 02-04 08:18:36.150: DEBUG/dalvikvm(9060): GC freed 564 objects / 27840 bytes in 89ms 02-04 08:18:36.630: DEBUG/dalvikvm(22167): GC freed 2437 objects / 554000 bytes in 35ms 02-04 08:18:38.760: DEBUG/dalvikvm(6709): GC freed 8309 objects / 545032 bytes in 36ms 02-04 08:18:39.270: DEBUG/dalvikvm(1129): GC freed 6958 objects / 278352 bytes in 107ms 02-04 08:18:39.970: DEBUG/dalvikvm(22167): GC freed 2915 objects / 560312 bytes in 38ms 02-04 08:18:41.260: DEBUG/dalvikvm(6184): GC freed 373 objects / 26152 bytes in 205ms 02-04 08:18:42.780: DEBUG/dalvikvm(6709): GC freed 7212 objects / 447696 bytes in 36ms 02-04 08:18:43.160: DEBUG/dalvikvm(22167): GC freed 3106 objects / 561824 bytes in 39ms 02-04 08:18:46.310: DEBUG/dalvikvm(22167): GC freed 3110 objects / 564080 bytes in 45ms 02-04 08:18:46.650: DEBUG/dalvikvm(6709): GC freed 7508 objects / 468832 bytes in 36ms 02-04 08:18:48.820: DEBUG/dalvikvm(31712): GC freed 13795 objects / 828232 bytes in 203ms 02-04 08:18:49.040: DEBUG/dalvikvm(1129): GC freed 6918 objects / 276224 bytes in 109ms 02-04 08:18:49.640: DEBUG/dalvikvm(22167): GC freed 2952 objects / 562168 bytes in 37ms 02-04 08:18:50.630: DEBUG/dalvikvm(6709): GC freed 8332 objects / 549680 bytes in 35ms 02-04 08:18:52.770: DEBUG/dalvikvm(22167): GC freed 3108 objects / 563192 bytes in 37ms 02-04 08:18:54.400: DEBUG/dalvikvm(6709): GC freed 7509 objects / 469016 bytes in 35ms 02-04 08:18:55.900: DEBUG/dalvikvm(22167): GC freed 3121 objects / 572920 bytes in 38ms 02-04 08:18:58.150: DEBUG/dalvikvm(6709): GC freed 7408 objects / 465456 bytes in 35ms 02-04 08:18:58.710: DEBUG/dalvikvm(1129): GC freed 6908 objects / 276440 bytes in 107ms 02-04 08:18:59.190: DEBUG/dalvikvm(22167): GC freed 3160 objects / 563144 bytes in 38ms 02-04 08:19:02.080: DEBUG/dalvikvm(6709): GC freed 7436 objects / 468040 bytes in 36ms 02-04 08:19:02.380: DEBUG/dalvikvm(22167): GC freed 3104 objects / 557600 bytes in 39ms 02-04 08:19:05.050: DEBUG/dalvikvm(22167): GC freed 2860 objects / 570072 bytes in 35ms 02-04 08:19:05.810: DEBUG/dalvikvm(6709): GC freed 7508 objects / 469080 bytes in 35ms 02-04 08:19:06.500: DEBUG/skia(22167): --- decoder->decode returned false 02-04 08:19:07.960: DEBUG/dalvikvm(22167): GC freed 2747 objects / 520008 bytes in 36ms 02-04 08:19:08.180: DEBUG/dalvikvm(1129): GC freed 7866 objects / 317304 bytes in 107ms 02-04 08:19:09.540: DEBUG/dalvikvm(6709): GC freed 8220 objects / 539688 bytes in 36ms 02-04 08:19:10.810: DEBUG/dalvikvm(22167): GC freed 2898 objects / 596824 bytes in 37ms 02-04 08:19:13.360: DEBUG/dalvikvm(22167): GC freed 2503 objects / 398936 bytes in 35ms 02-04 08:19:13.370: INFO/dalvikvm-heap(22167): Grow heap (frag case) to 5.029MB for 570264-byte allocation 02-04 08:19:13.400: DEBUG/dalvikvm(22167): GC freed 702 objects / 24976 bytes in 31ms 02-04 08:19:13.400: DEBUG/skia(22167): --- decoder->decode returned false 02-04 08:19:13.540: DEBUG/dalvikvm(6709): GC freed 7481 objects / 466544 bytes in 36ms 02-04 08:19:15.600: DEBUG/WifiService(1129): got ACTION_DEVICE_IDLE 02-04 08:19:15.960: INFO/wpa_supplicant(2522): CTRL-EVENT-DRIVER-STATE STOPPED 02-04 08:19:15.960: VERBOSE/WifiMonitor(1129): Event [CTRL-EVENT-DRIVER-STATE STOPPED] 02-04 08:19:17.270: DEBUG/dalvikvm(22167): GC freed 2372 objects / 1266992 bytes in 36ms 02-04 08:19:17.520: DEBUG/dalvikvm(6709): GC freed 7996 objects / 519128 bytes in 37ms 02-04 08:19:18.150: DEBUG/dalvikvm(1129): GC freed 7110 objects / 285032 bytes in 108ms 02-04 08:19:20.460: DEBUG/dalvikvm(22167): GC freed 3327 objects / 565264 bytes in 36ms 02-04 08:19:21.250: DEBUG/dalvikvm(6709): GC freed 7632 objects / 486024 bytes in 37ms 02-04 08:19:26.470: DEBUG/dalvikvm(31774): GC freed 345 objects / 16160 bytes in 96ms 02-04 08:19:30.423: WARN/System.err(22536): java.lang.Exception: You must call com.mercuryintermedia.productconfiguration.initialize() first 02-04 08:19:30.423: WARN/System.err(22536): at com.mercuryintermedia.ProductConfiguration.getProductName(ProductConfiguration.java:136) 02-04 08:19:30.423: WARN/System.err(22536): at com.mercuryintermedia.api.rest.Item.getPublishingContainersItems(Item.java:15) 02-04 08:19:30.423: WARN/System.err(22536): at com.mercuryintermedia.mflow.ContainerHelper.getContainerFromServer(ContainerHelper.java:68) 02-04 08:19:30.423: WARN/System.err(22536): at com.mercuryintermedia.mflow.ContainerHelper.run(ContainerHelper.java:46) 02-04 08:20:05.280: DEBUG/dalvikvm(1813): GC freed 741 objects / 36840 bytes in 91ms 02-04 08:20:23.580: DEBUG/WifiService(1129): ACTION_BATTERY_CHANGED pluggedType: 2 02-04 08:20:30.423: WARN/System.err(22536): java.lang.Exception: You must call com.mercuryintermedia.productconfiguration.initialize() first 02-04 08:20:30.423: WARN/System.err(22536): at com.mercuryintermedia.ProductConfiguration.getProductName(ProductConfiguration.java:136) 02-04 08:20:30.423: WARN/System.err(22536): at com.mercuryintermedia.api.rest.Item.getPublishingContainersItems(Item.java:15) 02-04 08:20:30.423: WARN/System.err(22536): at com.mercuryintermedia.mflow.ContainerHelper.getContainerFromServer(ContainerHelper.java:68) 02-04 08:20:30.423: WARN/System.err(22536): at com.mercuryintermedia.mflow.ContainerHelper.run(ContainerHelper.java:46) 02-04 08:20:53.970: INFO/FastDormancyManager(1129): Fast Dormant executed. ExecuteCount:2683 NonExecuteCount:25773 I really hope you can help me.

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  • Reliable test for MSDTC promoting transactions to distributed?

    - by Oded
    How can I reliably check that MSDTC has promoted a transaction to a distributed transaction, from .net code? Currently a co-worker is testing this by shutting down the coordinator on his machine - if an exception is thrown this is taken as evidence that an attempt to promote the transaction has occurred. Is this a valid test?

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  • technologies beside scaling web applications in a distributed nature

    - by wik
    Hello, I am interested in theory to scale web applications in a distributed nature, i.e. when there is some platform/stack can be extended by others applications running on different servers, etc. I am researching this field and feels the lack of the right keywords :) Interesting concepts found so far: opensocial through API, like shopify does (shopify it's a hosted ecommerce solution) semantic web not quite sure about this one Am I on the right way or am I lost anything? :) Thanks.

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  • distributed system programming with php

    - by ranganaMIT
    Hi guys, I'm doing a system for a hospital in my country as the final year project of my degree, my supervisor specially asked me to use php and mysql for this. i don't have any experience with distributed systems and php programming, can any one help me out to build my base and improove my knowledge stating some sites, books to refer to overcome this matter. regards, rangana.

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  • Unit test distributed software

    - by user262646
    Is there any tool or framework able to make it easier to "unit test" distributed software written in Java? My system under test is a peer-to-peer software, and I'd like to perform testing using something like PNUnit, but with Java instead of .Net.

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  • Why is TransactionScope using a distributed transaction when I am only using LinqToSql and Ado.Net

    - by Ian Ringrose
    We are having problems on one machine, with the error message: "MSDTC on server XXX is unavailable." The code is using a TransactionScope to wrap some LingToSql database code; there is also some raw Ado.net inside of the transaction. As only a single sql database (2005) is being accessed, why is a distributed transaction being used at all? (I don’t wish to know how to enable MSDTC, as the code needs to work on the server with their current setup)

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  • PHP SoapClient: Problems with Distributed WSDL File

    - by Dave
    Hello, I have a problem using a distributed WSDL File ( scheme / other definitions are declared outside the actual wsdl) with php's SoapClient. This is the Fault Message I get: SOAP-ERROR: Parsing WSDL: 'getSomeInfo' already defined. After some googling , it seems to be a bug inside php as someone else discovered exactly the same problem: http://bugs.php.net/bug.php?id=45282 Has there been any bug fix(es)? Any solution to work around this bug? PS: I think posting a code snippet is senseless, since the invocation of the SoapClient ctor using just the WSDL is the only that fails. Thank you in advance, Dave

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  • What are pinned objects?

    - by sagie
    Hi. I am trying to find a memory leak using ants memory profiler, and I've encountered in a new term: Pinned objects. Can some one give me a good & simple explanation about what this objects are, How can I pinn/Unpinn objects, and detect who pinned objects? Thanks

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  • How to make distributed builds using XCode 3.2 on OS X 10.6

    - by Sorin Sbarnea
    After I upgraded using a clean install from OS X 10.5 to 10.6.2 and upgraded the XCode to 3.2.1 I wasn't able to use distributed builds feature anymore. There are several issues that I detected: In most cases Bonjour is not detecting the other computers even they are on the same switch. I added a custom 'set' where I added manually the IP addreses of each computer. Even so I still get status: "unreachable" on them.BTW, ping does work without problems. Both share my computer for shared workgroup builds (distcc) and distribute builds via shared workgroup builds options are checked.

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  • What grid distributed computing frameworks are currently favoured for trading systems

    - by Rich
    There seems to a quite a few grid computing frameworks out there, but which ones are actually being used to any great extent by the investment banks for purposes of low latency distributing calculation? I'd be interested to hear answers covering both windows,Linux and cross platform. Also, what RPC mechanisms seem to be favoured most? I've heard that for reason of low latency and speed, the calculations themselves are quite often written in C++/C as calculations running on VMs are several orders of magnitude slower than native code. Does this seem to be a common scenario in practice? e.g distributed .NET grid framework running calculations written in native c++/c?

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  • Enumerating combinations in a distributed manner

    - by Reyzooti
    I have a problem where I must analyse 500C5 combinations (255244687600) of something. Distributing it over a 10 node cluster where each cluster processes roughly 10^6 combinations per second means the job will be complete in about 7hours. The problem I have is distributing the 255244687600 combinations over the 10 nodes. I'd like to present each node with 25524468760, however the algorithms I'm using can only produce the combinations sequentially, I'd like to be able to pass the set of elements and a range of combination indicies eg: [0-10^7) or [10^7,2.0 10^7) etc and have the nodes themselves figure out the combinations. The algorithms I'm using at the moment are from the following: http://home.roadrunner.com/~hinnant/combinations.html A logical question I've considered using a master node, that enumerates each of the combinations and sends work to each of the nodes, however the overhead incurred in iterating the combinations from a single node and communicating back and forth work is enormous, and will subsequently lead to the master node becoming the bottleneck. Are there any good combination iterating algorithms geared up for efficient/optimal distributed enumeration?

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  • Distributed development systems

    - by Nathan Adams
    I am interested in a system that allows for distributed development with an authentication piece. What do I mean by that? Ok so lets take SVN, SVN keeps track of revisions and doesn't care who submits, as long as you have the right to submit you can submit, really, to any part in the repository. Where does my system come into play? Being able to granulate access control and give a stackoverflow like feel to the environment. In the system I am describing we have 4 users Bob, Alice, Dan, Joe. Bob is a project managed, Alice and Dan are programmers under Bob and Joe is a random programmer on the internet who wants to help. Ideally in this system, Bob can commit any changes and won't require approval. Alice and Dan can commit to their branches, or a branch, but a commit to the trunk would need approval by Bob. This is where Joe comes in, wants to help, however, you just don't want to give him the keys to the kingdom just yet so to speak, so in my system you would setup a "low user" account. Any commits that Joe makes would need to be approved by Dan, Alice or both. However, in the system, Joe can build up "Karma" where after so many approved commits it would only need approval by one of the programmers, and then eventually no approval would be necessary. Does that make sense and do you know if a system like that exists? Or am I just crazy to even think such a system/environment would be possible?

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  • Distributed Lock Service over MySql/GigaSpaces/Netapp

    - by ripper234
    Disclaimer: I already asked this question, but without the deployment requirement. I got an answer that got 3 upvotes, and when I edited the question to include the deployment requirement the answer then became irrelevant. The reason I'm resubmitting is because SO considers the original question 'answered', even though I got no meaningful upvoted answer. I opened a uservoice submission about this problem. The reason I reposted is so StackOverflow consider the original question answered, so it doesn't show up on the 'unanswered questions' tab. Which distributed lock service would you use? Requirements are: A mutual exclusion (lock) that can be seen from different processes/machines lock...release semantics Automatic lock release after a certain timeout - if lock holder dies, it will automatically be freed after X seconds Java implementation Easy deployment - must not require complicated deployment beyond either Netapp, MySql or GigaSpaces. Must play well with those products (especially GigaSpaces - this is why TerraCotta was ruled out). Nice to have: .Net implementation If it's free: Deadlock detection / mitigation I'm not interested in answers like "it can be done over a database", or "it can be done over JavaSpaces" - I know. Relevant answers should only contain a ready, out-of-the-box, proven implementation.

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  • Distributed Cache with Serialized File as DataStore in Oracle Coherence

    - by user226295
    Weired but I am investigating the Oracle Coherence as a substitue for distribute cache. My primarr problem is that we dont have distribituted cache as such as of now in our app. Thats my major concern. And thats what I want to implement. So, lets say if I take up a machine and start a new (3rd) reading process, it will be able to connect to the cache and listen to the cache and will have a full set of cache triplicated (as of now its duplicated) Now thats waste from a common person stanpoint too. The size of the cache is 2 GB and without going distibuted its limiting us. Thats bring me to Coheremce. But now, we dont have database as persistent store too. we have the archival processes as our persistent store. (90 days worth of data) Ok now multiply that with soem where around 2 GB * 90 (thats the bare minimum we want to keep). Preliminary/Intermediate analysis of Coherence as a solution. And a (supposedly) brilliant thought crossed my mind. Why not have this as persistant storage with my distributed cache. Does Oracle Coherence support that. I will get rid of archiving infrastructure too (i hate daemon archiving processes). For some starnge reasons, I dont wanna go to the DB to replace those flat files. What say?, can Coherence be my savior? Any other stable alternate too. (Coherence is imposed on me by big guys, FYI)

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  • Experience with MooseFS?

    - by brown.2179
    Anyone have any experience using MooseFS? I want an easy distributed storage platform to store static data archive of about 10 TB and serve it to 20-40 nodes. Also I want to be able to add storage as the archive grows without having to rebuild the filesystem. I don't care if it's a bit slow. I just want it to be simple and stable. Basically from what I can see for OS X it's between MooseFS and Gluster. Any other suggestions?

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  • Using java to send/receive different objects through UDP

    - by AAA
    Hello everyone, I am writing a program in Java where there are communications between two or more machines using UDP. My application sends objects after serializing them through the network to the other machine where it will be deserialized and dealt with it. I was successful in sending one kind of objects so far. My problem is that I want the sender to be able to send different kind of objects, and for the receiver to be able to receive them and cast them again to their appropriate types. However, since UDP allocates a byte buffer then receive the data into the buffer, it is impossible to cast or detect the type of the received object as different objects have different sizes. Is there is a way that I can use to send different kind of objects using UDP and then receive them at the other end? (I don't ask for code here, just some ideas) Thanks

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  • Good programming style when handling multiple objects

    - by Glitch
    I've been programming a software version of a board game. Thus far I have written the classes which will correspond to physical objects on the game board. I'm well into writing the program logic, however I've found that many of the logic classes require access to the same objects. At first I was passing the appropriate objects to methods as they were called, but this was getting very tedious, particularly when the methods required many objects to perform their tasks. To solve this, I created a class which initialises and stores all the objects I need. This allows me to access an object from any class by calling Assets.dice(), for example. But now that I've thought about it, this doesn't seem right. This is why I'm here, I fear that I've created some sort of god class. Is this fear unfounded, or have I created a recipe for disaster?

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  • Oracle Fusion Distributed Order Orchestration

    Designed from the ground-up using the latest technology advances and incorporating the best practices gathered from Oracle's thousands of customers, Fusion Applications are 100 percent open standards-based business applications that set a new standard for the way we innovate, work and adopt technology. Delivered as a complete suite of modular applications, Fusion Applications work with your existing portfolio to evolve your business to a new level of performance. In this AppCast, part of a special series on Fusion Applications, you hear lean how Oracle Fusion Distributed Order Orchestration can help companies improve customer service, reduce fulfillment costs, and optimize fulfillment decision making. Supporting a strategy for improving operational efficiency and boosting customer satisfaction, Fusion Distributed Order Orchestration alleviates or tempers critical production challenges many organizations face today by consolidating order information into a central location. You'll also discover how Fusion Distributed Order Orchestration works with your existing order management solutions.

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  • Experience with MooseFS?

    - by brown.2179
    Anyone have any experience using MooseFS? I want an easy distributed storage platform to store static data archive of about 10 TB and serve it to 20-40 nodes. Also I want to be able to add storage as the archive grows without having to rebuild the filesystem. I don't care if it's a bit slow. I just want it to be simple and stable. Basically from what I can see for OS X it's between MooseFS and Gluster. Any other suggestions?

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  • Distributed cache and improvement

    - by philipl
    Have this question from interview: Web Service function given x static HashMap map (singleton created) if (!map.containsKey(x)) { perform some function to retrieve result y map.put(x, y); } return y; The interviewer asked general question such as what is wrong with this distributed cache implementation. Then asked how to improve on it, due to distributed servers will have different cached key pairs in the map. There are simple mistakes to be pointed out about synchronization and key object, but what really startled me was that this guy thinks that moving to database implementation solves the problem that different servers will have different map content, i.e., the situation when value x is not on server A but on server B, therefore redundant data has to be retrieved in server A. Does his thinking make any sense? (As I understand this is the basic cons for distributed cache against database model, seems he does not understand it at all) What is the typical solution for the cache growth issue (weak reference?) and sync issue (do not know which server has the key already cached - use load balancing)? Thanks

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  • Tuning Distributed Applications to Access Big Data

    Distributed applications are just that: distributed across one or more hardware platforms across the enterprise. The database administrator (DBA) has the unenviable task of monitoring these environments and configuring and tuning the database server to meet multiple needs. As multiple distributed applications now require access to a very large data store, what tuning options are available to help? Get your SQL Server database under version control now!Version control is standard for applications, but databases haven’t caught up. So how can you bring database development up to speed? Why should you start? Find out…

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  • Looking for efficient scaling patterns for Silverlight application with distributed text-file data s

    - by Edward Tanguay
    I'm designing a Silverlight software solution for students and teachers to record flashcards, e.g. words and phrases that students find while reading and errors that teachers notice while teaching. Requirements are: each person publishes his own flashcards in a file on a web server, e.g. http://:www.mywebserver.com/flashcards.txt other people subscribe to that person's flashcards by using a Silverlight flashcard reader that I have developed and entering the URLs of flashcard files they want to subscribe to, URLs and imported flashcards being saved in IsolatedStorage the flashcards.txt file has the following simple format: title, then blocks of question/answers: Jim Smith's flashcards from English class 53-222, winter semester 2009 ==fla Das kann nicht sein. That can't be. ==fla Es sei denn, er kommt nicht. Unless he doesn't come. The user then makes public the URL to his flashcard file and other readers begin reading in his flashcards. In order to lower the bar for non-technical users to contribute, it will even be possible for them to save this text in a Google Document, which they publish and distribute the URL. The flashcard readers will then recognize it is a google document and perform the necessary screen scraping to get at the raw text. I have two technical questions about this approach: What is a best way to plan now for scalability issues: e.g. if your reader is subscribed to 10 flashcard files that are each 200K, it will have to download 2MB of text just to find out if any new flashcards are available. Or can I somehow accurately and consistently get at the last update date/time of text files on servers and published google docs? Each reader will have the ability to allow the person to test himself on imported flashcards and add meta information to them, e.g. categorize them, edit them, etc. This information will be stored in IsolatedStorage along with the important flashcards themselves. What is a good pattern to allow these readers to share and synchronize this meta data, e.g. so when you are looking at a flashcard you can see that 5 other people have made corrections to it. The best solution I can think of now is that the Silverlight readers will have to republish their data to a central database, but then there is the problem of uniquely identifying each flashcard, the best approach seems to be URL + position-in-file, or even better URL + original text of both question and answer fields, but both of these have their obvious drawbacks. The main requirement is that the bar for participation is kept as low as possible, i.e. type text in a google document, publish it, distribute the URL, and you're publishing within the flashcard community. So I want to come up with the most efficient technical solutions in order to compensate for the lack of database, lack of unique ids, etc. For those who have designed or developed similar non-traditional, distributed database projects like this, what advice, experience or best-practice tips you can share on the above two points?

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  • Choosing a distributed shared memory solution

    - by mindas
    I have a task to build a prototype for a massively scalable distributed shared memory (DSM) app. The prototype would only serve as a proof-of-concept, but I want to spend my time most effectively by picking the components which would be used in the real solution later on. The aim of this solution is to take data input from an external source, churn it and make the result available for a number of frontends. Those "frontends" would just take the data from the cache and serve it without extra processing. The amount of frontend hits on this data can literally be millions per second. The data itself is very volatile; it can (and does) change quite rapidly. However the frontends should see "old" data until the newest has been processed and cached. The processing and writing is done by a single (redundant) node while other nodes only read the data. In other words: no read-through behaviour. I was looking into solutions like memcached however this particular one doesn't fulfil all our requirements which are listed below: The solution must at least have Java client API which is reasonably well maintained as the rest of app is written in Java and we are seasoned Java developers; The solution must be totally elastic: it should be possible to add new nodes without restarting other nodes in the cluster; The solution must be able to handle failover. Yes, I realize this means some overhead, but the overall served data size isn't big (1G max) so this shouldn't be a problem. By "failover" I mean seamless execution without hardcoding/changing server IP address(es) like in memcached clients when a node goes down; Ideally it should be possible to specify the degree of data overlapping (e.g. how many copies of the same data should be stored in the DSM cluster); There is no need to permanently store all the data but there might be a need of post-processing of some of the data (e.g. serialization to the DB). Price. Obviously we prefer free/open source but we're happy to pay a reasonable amount if a solution is worth it. In any way, paid 24hr/day support contract is a must. The whole thing has to be hosted in our data centers so SaaS offerings like Amazon SimpleDB are out of scope. We would only consider this if no other options would be available. Ideally the solution would be strictly consistent (as in CAP); however, eventual consistence can be considered as an option. Thanks in advance for any ideas.

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