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• Database Owner Conundrum

  - by Johnm

  Have you ever restored a database from a production environment on Server A into a development environment on Server B and had some items, such as Service Broker, mysteriously cease functioning? You might want to consider reviewing the database owner property of the database. The Scenario Recently, I was developing some messaging functionality that utilized the Service Broker feature of SQL Server in a development environment. Within the instance of the development environment resided two databases: One was a restored version of a production database that we will call "RestoreDB". The second database was a brand new database that has yet to exist in the production environment that we will call "DevDB". The goal is to setup a communication path between RestoreDB and DevDB that will later be implemented into the production database. After implementing all of the Service Broker objects that are required to communicate within a database as well as between two databases on the same instance I found myself a bit confounded. My testing was showing that the communication was successful when it was occurring internally within DevDB; but the communication between RestoreDB and DevDB did not appear to be working. Profiler to the rescue After carefully reviewing my code for any misspellings, missing commas or any other minor items that might be a syntactical cause of failure, I decided to launch Profiler to aid in the troubleshooting. After simulating the cross database messaging, I noticed the following error appearing in Profiler: An exception occurred while enqueueing a message in the target queue. Error: 33009, State: 2. The database owner SID recorded in the master database differs from the database owner SID recorded in database '[Database Name Here]'. You should correct this situation by resetting the owner of database '[Database Name Here]' using the ALTER AUTHORIZATION statement. Now, this error message is a helpful one. Not only does it identify the issue in plain language, it also provides a potential solution. An execution of the following query that utilizes the catalog view sys.transmission_queue revealed the same error message for each communication attempt: SELECT     * FROM        sys.transmission_queue; Seeing the situation as a learning opportunity I dove a bit deeper. Reviewing the database properties  The owner of a specific database can be easily viewed by right-clicking the database in SQL Server Management Studio and selecting the "properties" option. The owner is listed on the "General" page of the properties screen. In my scenario, the database in the production server was created by Frank the DBA; therefore his server login appeared as the owner: "ServerName\Frank". While this is interesting information, it certainly doesn't tell me much in regard to the SID (security identifier) and its existence, or lack thereof, in the master database as the error suggested. I pulled together the following query to gather more interesting information: SELECT     a.name     , a.owner_sid     , b.sid     , b.name     , b.type_desc FROM        master.sys.databases a     LEFT OUTER JOIN master.sys.server_principals b         ON a.owner_sid = b.sid WHERE     a.name not in ('master','tempdb','model','msdb'); This query also helped identify how many other user databases in the instance were experiencing the same issue. In this scenario, I saw that there were no matching SIDs in server_principals to the owner SID for my database. What login should be used as the database owner instead of Frank's? The system stored procedure sp_helplogins will provide a list of the valid logins that can be used. Here is an example of its use, revealing all available logins: EXEC sp_helplogins;  Fixing a hole The error message stated that the recommended solution was to execute the ALTER AUTHORIZATION statement. The full statement for this scenario would appear as follows: ALTER AUTHORIZATION ON DATABASE:: [Database Name Here] TO [Login Name]; Another option is to execute the following statement using the sp_changedbowner system stored procedure; but please keep in mind that this stored procedure has been deprecated and will likely disappear in future versions of SQL Server: EXEC dbo.sp_changedbowner @loginname = [Login Name]; .And They Lived Happily Ever After Upon changing the database owner to an existing login and simulating the inner and cross database messaging the errors have ceased. More importantly, all messages sent through this feature now successfully complete their journey. I have added the ownership change to my restoration script for the development environment.

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• 2D metaball liquid effect - how to feed output of one rendering pass as input to another shader

  - by Guye Incognito

  I'm attempting to make a shader for unity3d web project. I want to implement something like in the great answer by DMGregory in this question. in order to achieve a final look something like this.. Its metaballs with specular and shading. The steps to make this shader are. 1. Convert the feathered blobs into a heightmap. 2. Generate a normalmap from the heightmap 3. Feed the normal map and height map into a standard unity shader, for instance transparent parallax specular. I pretty much have all the pieces I need assembled but I am new to shaders and need help putting them together I can generate a heightmap from the blobs using some fragment shader code I wrote (I'm just using the red channel here cus i dont know if you can access the brightness) half4 frag (v2f i) : COLOR{ half4 texcol,finalColor; texcol = tex2D (_MainTex, i.uv); finalColor=_MyColor; if(texcol.r<_botmcut) { finalColor.r= 0; } else if((texcol.r>_topcut)) { finalColor.r= 0; } else { float r = _topcut-_botmcut; float xpos = _topcut - texcol.r; finalColor.r= (_botmcut + sqrt((xpos*xpos)-(r*r)))/_constant; } return finalColor; } turns these blobs.. into this heightmap Also I've found some CG code that generates a normal map from a height map. The bit of code that makes the normal map from finite differences is here void surf (Input IN, inout SurfaceOutput o) { o.Albedo = fixed3(0.5); float3 normal = UnpackNormal(tex2D(_BumpMap, IN.uv_MainTex)); float me = tex2D(_HeightMap,IN.uv_MainTex).x; float n = tex2D(_HeightMap,float2(IN.uv_MainTex.x,IN.uv_MainTex.y+1.0/_HeightmapDimY)).x; float s = tex2D(_HeightMap,float2(IN.uv_MainTex.x,IN.uv_MainTex.y-1.0/_HeightmapDimY)).x; float e = tex2D(_HeightMap,float2(IN.uv_MainTex.x-1.0/_HeightmapDimX,IN.uv_MainTex.y)).x; float w = tex2D(_HeightMap,float2(IN.uv_MainTex.x+1.0/_HeightmapDimX,IN.uv_MainTex.y)).x; float3 norm = normal; float3 temp = norm; //a temporary vector that is not parallel to norm if(norm.x==1) temp.y+=0.5; else temp.x+=0.5; //form a basis with norm being one of the axes: float3 perp1 = normalize(cross(norm,temp)); float3 perp2 = normalize(cross(norm,perp1)); //use the basis to move the normal in its own space by the offset float3 normalOffset = -_HeightmapStrength * ( ( (n-me) - (s-me) ) * perp1 + ( ( e - me ) - ( w - me ) ) * perp2 ); norm += normalOffset; norm = normalize(norm); o.Normal = norm; } Also here is the built-in transparent parallax specular shader for unity. Shader "Transparent/Parallax Specular" { Properties { _Color ("Main Color", Color) = (1,1,1,1) _SpecColor ("Specular Color", Color) = (0.5, 0.5, 0.5, 0) _Shininess ("Shininess", Range (0.01, 1)) = 0.078125 _Parallax ("Height", Range (0.005, 0.08)) = 0.02 _MainTex ("Base (RGB) TransGloss (A)", 2D) = "white" {} _BumpMap ("Normalmap", 2D) = "bump" {} _ParallaxMap ("Heightmap (A)", 2D) = "black" {} } SubShader { Tags {"Queue"="Transparent" "IgnoreProjector"="True" "RenderType"="Transparent"} LOD 600 CGPROGRAM #pragma surface surf BlinnPhong alpha #pragma exclude_renderers flash sampler2D _MainTex; sampler2D _BumpMap; sampler2D _ParallaxMap; fixed4 _Color; half _Shininess; float _Parallax; struct Input { float2 uv_MainTex; float2 uv_BumpMap; float3 viewDir; }; void surf (Input IN, inout SurfaceOutput o) { half h = tex2D (_ParallaxMap, IN.uv_BumpMap).w; float2 offset = ParallaxOffset (h, _Parallax, IN.viewDir); IN.uv_MainTex += offset; IN.uv_BumpMap += offset; fixed4 tex = tex2D(_MainTex, IN.uv_MainTex); o.Albedo = tex.rgb * _Color.rgb; o.Gloss = tex.a; o.Alpha = tex.a * _Color.a; o.Specular = _Shininess; o.Normal = UnpackNormal(tex2D(_BumpMap, IN.uv_BumpMap)); } ENDCG } FallBack "Transparent/Bumped Specular" }

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• BizTalk: Sample: Context routing and Throttling with orchestration

  - by Leonid Ganeline

  The sample demonstrates using orchestration for throttling and using context routing. Usually throttling is implemented on the host level (in BizTalk 2010 we can also using the host instance level throttling). Here is demonstrated the throttling with orchestration convoy that slows down message flow from some customers. Sample implements sort of quality service agreement layer for different kind of customers. The sample demonstrates the context routing between orchestrations. It has several advantages over the content routing. For example, we don’t have to create the property schema and promote properties on the schemas; we don’t have to change the message content to change routing. Use case:  The BizTalk application has a main processing orchestration that process all input messages. The application usually works as an OLTP application. Input messages came in random order without peaks, typical scenario for the on-line users. But sometimes the big data batch payloads come. These batches overload processing orchestrations. All processes, activated by on-line users after the payload, come to the same queue and are processed only after the payload. Result is on-line users can see significant delay in processing. It can be minutes or hours, depending of the batch size. Requirements: On-line user’s processing should work without delays. Big batches cannot disturb on-line users. There should be higher priority for the on-line users and the lower priority for the batches. Design: Decision is to divide the message flow in two branches, one for on-line users and second for batches. Branch with batches provides messages to the processing line with low priority, and the on-line user’s branch – with high priority. All messages are provided by hi-speed receive port. BTS.ReceivePortName context property is used for routing. The Router orchestration separates messages sent from on-line users and from the batch messages. But the Router does not use the BizTalk provided value of this property, the Router set up this value by itself. Router uses the content of the messages to decide if it is from on-line users or from batches. The message context property the BTS.ReceivePortName is changed respectively, its value works as a recipient address, as the “To” address for the next recipient orchestrations. Those next orchestrations are the BatchBottleneck and the MainProcess orchestrations. Messages with context equal “ToBatch” are filtered up by the BatchBottleneck orchestration. It is a unified convoy orchestration and it throttles the message flow, delaying the message delivery to the MainProcess orchestration. The BatchBottleneck orchestration changes the message context to the “ToProcess” and sends messages one after another with small delay in between. Delay can be configured in the BizTalk config file as:                 <appSettings>                                 <add key="GLD_Tests_TwoWayRouting_BatchBottleneck_DelayMillisec" value="100"/>                 </appSettings>   Of course, messages with context equal “ToProcess” are filtered up by the MainProcess orchestration.   NOTES: Filters with string values: In Orchestrations (the first Receive shape in orchestration) use string values WITH quotes; in Send Ports use string values WITHOUT quotes. Filters on the Send Ports are dynamic; we can change them in run-time. Filters on the Orchestrations are static; we can change them only in design-time. To check the existence of the promoted property inside orchestration use the Expression shape with construction like this:       if (BTS.ReceivePortName exists myMessage) { …; } It is not possible in the Message Assignment shape because using the “if” statement inside Message Assignment is prohibited. Several predefined context properties can behave in specific way. Say MessageTracking.OriginatingMessage or XMLNORM.DocumentSpecName, they are required some internal rules should be applied to the format or usage of this properties. MessageTracking.* parameters require you have to use tracking and you can get unexpected run-time errors in some cases. My recommendation is - use very limited set of the predefined context properties. To “attach” the new promoted property to the message, we have to use correlation. The correlation type should include this property. [Here is a good explanation by Saravana ] The sample code is here [sorry, temporary trubles with CodePlex].

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• Right-Time Retail Part 2

  - by David Dorf

  This is part two of the three-part series. Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Right-Time Integration Of course these real-time enabling technologies are only as good as the systems that utilize them, and it only takes one bottleneck to slow everyone else down. What good is an immediate stock-out notification if the supply chain can’t react until tomorrow? Since being formed in 2006, Oracle Retail has been not only adding more integrations between systems, but also modernizing integrations for appropriate speed. Notice I tossed in the word “appropriate.” Not everything needs to be real-time – again, we’re talking about Right-Time Retail. The speed of data capture, analysis, and execution must be synchronized or you’re wasting effort. Unfortunately, there isn’t an enterprise-wide dial that you can crank-up for your estate. You’ll need to improve things piecemeal, with people and processes as limiting factors while choosing the appropriate types of integrations. There are three integration styles we see in the retail industry. First is batch. I know, the word “batch” just sounds slow, but this pattern is less about velocity and more about volume. When there are large amounts of data to be moved, you’ll want to use batch processes. Our technology of choice here is Oracle Data Integrator (ODI), which provides a fast version of Extract-Transform-Load (ETL). Instead of the three-step process, the load and transform steps are combined to save time. ODI is a key technology for moving data into Retail Analytics where we can apply science. Performing analytics on each sale as it occurs doesn’t make any sense, so we batch up a statistically significant amount and submit all at once. The second style is fire-and-forget. For some types of data, we want the data to arrive ASAP but immediacy is not necessary. Speed is less important than guaranteed delivery, so we use message-oriented middleware available in both Weblogic and the Oracle database. For example, Point-of-Service transactions are queued for delivery to Central Office at corporate. If the network is offline, those transactions remain in the queue and will be delivered when the network returns. Transactions cannot be lost and they must be delivered in order. (Ever tried processing a return before the sale?) To enhance the standard queues, we offer the Retail Integration Bus (RIB) to help the management and monitoring of fire-and-forget messaging in the enterprise. The third style is request-response and is most commonly implemented as Web services. This is a synchronous message where the sender waits for a response. In this situation, the volume of data is small, guaranteed delivery is not necessary, but speed is very important. Examples include the website checking inventory, a price lookup, or processing a credit card authorization. The Oracle Service Bus (OSB) typically handles the routing of such messages, and we’ve enhanced its abilities with the Retail Service Backbone (RSB). To better understand these integration patterns and where they apply within the retail enterprise, we’re providing the Retail Reference Library (RRL) at no charge to Oracle Retail customers. The library is composed of a large number of industry business processes, including those necessary to support Commerce Anywhere, as well as detailed architectural diagrams. These diagrams allow implementers to understand the systems involved in integrations and the specific data payloads. Furthermore, with our upcoming release we’ll be providing a new tool called the Retail Integration Console (RIC) that allows IT to monitor and manage integrations from a single point. Using RIC, retailers can quickly discern where integration activity is occurring, volume statistics, average response times, and errors. The dashboards provide the ability to dive down into the architecture documentation to gather information all the way down to the specific payload. Retailers that want real-time integrations will also need real-time monitoring of those integrations to ensure service-level agreements are maintained. Part 3 looks at marketing.

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• No More NCrunch For Me

  - by Steve Wilkes

  When I opened up Visual Studio this morning, I was greeted with this little popup: NCrunch is a Visual Studio add-in which runs your tests while you work so you know if and when you've broken anything, as well as providing coverage indicators in the IDE and coverage metrics on demand. It recently went commercial (which I thought was fair enough), and time is running out for the free version I've been using for the last couple of months. From my experiences using NCrunch I'm going to let it expire, and go about my business without it. Here's why. Before I start, let me say that I think NCrunch is a good product, which is to say it's had a positive impact on my programming. I've used it to help test-drive a library I'm making right from the start of the project, and especially at the beginning it was very useful to have it run all my tests whenever I made a change. The first problem is that while that was cool to start with, it’s recently become a bit of a chore. Problems Running Tests NCrunch has two 'engine modes' in which it can run tests for you - it can run all your tests when you make a change, or it can figure out which tests were impacted and only run those. Unfortunately, it became clear pretty early on that that second option (which is marked as 'experimental') wasn't really working for me, so I had to have it run everything. With a smallish number of tests and while I was adding new features that was great, but I've now got 445 tests (still not exactly loads) and am more in a 'clean and tidy' mode where I know that a change I'm making will probably only affect a particular subset of the tests. With that in mind it's a bit of a drag sitting there after I make a change and having to wait for NCrunch to run everything. I could disable it and manually run the tests I know are impacted, but then what's the point of having NCrunch? If the 'impacted only' engine mode worked well this problem would go away, but that's not what I found. Secondly, what's wrong with this picture? I've got 445 tests, and NCrunch has queued 455 tests to run. So it's queued duplicate tests - in this quickly-screenshotted case 10, but I've seen the total queue get up over 600. If I'm already itchy waiting for it to run all my tests against a change I know only affects a few, I'm even itchier waiting for it to run a lot of them twice. Problems With Code Coverage NCrunch marks each line of code with a dot to say if it's covered by tests - a black dot says the line isn't covered, a red dot says it's covered but at least one of the covering tests is failing, and a green dot means all the covering tests pass. It also calculates coverage statistics for you. Unfortunately, there's a couple of flaws in the coverage. Firstly, it doesn't support ExcludeFromCodeCoverage attributes. This feature has been requested and I expect will be included in a later release, but right now it doesn't. So this: ...is counted as a non-covered line, and drags your coverage statistics down. Hmph. As well as that, coverage of certain types of code is missed. This: ...is definitely covered. I am 100% absolutely certain it is, by several tests. NCrunch doesn't pick it up, down go my coverage statistics. I've had NCrunch find genuinely uncovered code which I've been able to remove, and that's great, but what's the coverage percentage on this project? Umm... I don't know. Conclusion None of these are major, tool-crippling problems, and I expect NCrunch to get much better in future releases. The current version has some great features, like this: ...that's a line of code with a failing test covering it, and NCrunch can run that failing test and take me to that line exquisitely easily. That's awesome! I'd happily pay for a tool that can do that. But here's the thing: NCrunch (currently) costs $159 (about £100) for a personal licence and $289 (about £180) for a commercial one. I'm not sure which one I'd need as my project is a personal one which I'm intending to open-source, but I'm a professional, self-employed developer, but in any case - that seems like a lot of money for an imperfect tool. If it did everything it's advertised to do more or less perfectly I'd consider it, but it doesn't. So no more NCrunch for me.

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• Concurrency Utilities for Java EE Early Draft (JSR 236)

  - by arungupta

  Concurrency Utilities for Java EE is being worked as JSR 236 and has released an Early Draft. It provides concurrency capabilities to Java EE application components without compromising container integrity. Simple (common) and advanced concurrency patterns are easily supported without sacrificing usability. Using Java SE concurrency utilities such as java.util.concurrent API, java.lang.Thread and java.util.Timer in a Java EE application component such as EJB or Servlet are problematic since the container and server have no knowledge of these resources. JSR 236 enables concurrency largely by extending the Concurrency Utilities API developed under JSR-166. This also allows a consistency between Java SE and Java EE concurrency programming model. There are four main programming interfaces available: ManagedExecutorService ManagedScheduledExecutorService ContextService ManagedThreadFactory ManagedExecutorService is a managed version of java.util.concurrent.ExecutorService. The implementations of this interface are provided by the container and accessible using JNDI reference: <resource-env-ref>  <resource-env-ref-name>    concurrent/BatchExecutor  </resource-env-ref-name>  <resource-env-ref-type>    javax.enterprise.concurrent.ManagedExecutorService  </resource-env-ref-type><resource-env-ref> and available as: @Resource(name="concurrent/BatchExecutor")ManagedExecutorService executor; Its recommended to bind the JNDI references in the java:comp/env/concurrent subcontext. The asynchronous tasks that need to be executed need to implement java.lang.Runnable or java.util.concurrent.Callable interface as: public class MyTask implements Runnable { public void run() { // business logic goes here }} OR public class MyTask2 implements Callable<Date> {  public Date call() { // business logic goes here   }} The task is then submitted to the executor using one of the submit method that return a Future instance. The Future represents the result of the task and can also be used to check if the task is complete or wait for its completion. Future<String> future = executor.submit(new MyTask(), String.class);. . .String result = future.get(); Another example to submit tasks is: class MyTask implements Callback<Long> { . . . }class MyTask2 implements Callback<Date> { . . . }ArrayList<Callable> tasks = new ArrayList<();tasks.add(new MyTask());tasks.add(new MyTask2());List<Future<Object>> result = executor.invokeAll(tasks); The ManagedExecutorService may be configured for different properties such as: Hung Task Threshold: Time in milliseconds that a task can execute before it is considered hung Pool Info Core Size: Number of threads to keep alive Maximum Size: Maximum number of threads allowed in the pool Keep Alive: Time to allow threads to remain idle when # of threads > Core Size Work Queue Capacity: # of tasks that can be stored in inbound buffer Thread Use: Application intend to run short vs long-running tasks, accordingly pooled or daemon threads are picked ManagedScheduledExecutorService adds delay and periodic task running capabilities to ManagedExecutorService. The implementations of this interface are provided by the container and accessible using JNDI reference: <resource-env-ref>  <resource-env-ref-name>    concurrent/BatchExecutor  </resource-env-ref-name>  <resource-env-ref-type>    javax.enterprise.concurrent.ManagedExecutorService  </resource-env-ref-type><resource-env-ref> and available as: @Resource(name="concurrent/timedExecutor")ManagedExecutorService executor; And then the tasks are submitted using submit, invokeXXX or scheduleXXX methods. ScheduledFuture<?> future = executor.schedule(new MyTask(), 5, TimeUnit.SECONDS); This will create and execute a one-shot action that becomes enabled after 5 seconds of delay. More control is possible using one of the newly added methods: MyTaskListener implements ManagedTaskListener {  public void taskStarting(...) { . . . }  public void taskSubmitted(...) { . . . }  public void taskDone(...) { . . . }  public void taskAborted(...) { . . . } }ScheduledFuture<?> future = executor.schedule(new MyTask(), 5, TimeUnit.SECONDS, new MyTaskListener()); Here, ManagedTaskListener is used to monitor the state of a task's future. ManagedThreadFactory provides a method for creating threads for execution in a managed environment. A simple usage is: @Resource(name="concurrent/myThreadFactory")ManagedThreadFactory factory;. . .Thread thread = factory.newThread(new Runnable() { . . . }); concurrent/myThreadFactory is a JNDI resource. There is lot of interesting content in the Early Draft, download it, and read yourself. The implementation will be made available soon and also be integrated in GlassFish 4 as well. Some references for further exploring ... Javadoc Early Draft Specification concurrency-ee-spec.java.net [email protected]

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• Implementing a Custom Coherence PartitionAssignmentStrategy

  - by jpurdy

  A recent A-Team engagement required the development of a custom PartitionAssignmentStrategy (PAS). By way of background, a PAS is an implementation of a Java interface that controls how a Coherence partitioned cache service assigns partitions (primary and backup copies) across the available set of storage-enabled members. While seemingly straightforward, this is actually a very difficult problem to solve. Traditionally, Coherence used a distributed algorithm spread across the cache servers (and as of Coherence 3.7, this is still the default implementation). With the introduction of the PAS interface, the model of operation was changed so that the logic would run solely in the cache service senior member. Obviously, this makes the development of a custom PAS vastly less complex, and in practice does not introduce a significant single point of failure/bottleneck. Note that Coherence ships with a default PAS implementation but it is not used by default. Further, custom PAS implementations are uncommon (this engagement was the first custom implementation that we know of). The particular implementation mentioned above also faced challenges related to managing multiple backup copies but that won't be discussed here. There were a few challenges that arose during design and implementation: Naive algorithms had an unreasonable upper bound of computational cost. There was significant complexity associated with configurations where the member count varied significantly between physical machines. Most of the complexity of a PAS is related to rebalancing, not initial assignment (which is usually fairly simple). A custom PAS may need to solve several problems simultaneously, such as: Ensuring that each member has a similar number of primary and backup partitions (e.g. each member has the same number of primary and backup partitions) Ensuring that each member carries similar responsibility (e.g. the most heavily loaded member has no more than one partition more than the least loaded). Ensuring that each partition is on the same member as a corresponding local resource (e.g. for applications that use partitioning across message queues, to ensure that each partition is collocated with its corresponding message queue). Ensuring that a given member holds no more than a given number of partitions (e.g. no member has more than 10 partitions) Ensuring that backups are placed far enough away from the primaries (e.g. on a different physical machine or a different blade enclosure) Achieving the above goals while ensuring that partition movement is minimized. These objectives can be even more complicated when the topology of the cluster is irregular. For example, if multiple cluster members may exist on each physical machine, then clearly the possibility exists that at certain points (e.g. following a member failure), the number of members on each machine may vary, in certain cases significantly so. Consider the case where there are three physical machines, with 3, 3 and 9 members each (respectively). This introduces complexity since the backups for the 9 members on the the largest machine must be spread across the other 6 members (to ensure placement on different physical machines), preventing an even distribution. For any given problem like this, there are usually reasonable compromises available, but the key point is that objectives may conflict under extreme (but not at all unlikely) circumstances. The most obvious general purpose partition assignment algorithm (possibly the only general purpose one) is to define a scoring function for a given mapping of partitions to members, and then apply that function to each possible permutation, selecting the most optimal permutation. This would result in N! (factorial) evaluations of the scoring function. This is clearly impractical for all but the smallest values of N (e.g. a partition count in the single digits). It's difficult to prove that more efficient general purpose algorithms don't exist, but the key take away from this is that algorithms will tend to either have exorbitant worst case performance or may fail to find optimal solutions (or both) -- it is very important to be able to show that worst case performance is acceptable. This quickly leads to the conclusion that the problem must be further constrained, perhaps by limiting functionality or by using domain-specific optimizations. Unfortunately, it can be very difficult to design these more focused algorithms. In the specific case mentioned, we constrained the solution space to very small clusters (in terms of machine count) with small partition counts and supported exactly two backup copies, and accepted the fact that partition movement could potentially be significant (preferring to solve that issue through brute force). We then used the out-of-the-box PAS implementation as a fallback, delegating to it for configurations that were not supported by our algorithm. Our experience was that the PAS interface is quite usable, but there are intrinsic challenges to designing PAS implementations that should be very carefully evaluated before committing to that approach.

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• Deduping your redundancies

  - by nospam(at)example.com (Joerg Moellenkamp)

  Robin Harris of Storagemojo pointed to an interesting article about about deduplication and it's impact to the resiliency of your data against data corruption on ACM Queue. The problem in short: A considerable number of filesystems store important metadata at multiple locations. For example the ZFS rootblock is copied to three locations. Other filesystems have similar provisions to protect their metadata. However you can easily proof, that the rootblock pointer in the uberblock of ZFS for example is pointing to blocks with absolutely equal content in all three locatition (with zdb -uu and zdb -r). It has to be that way, because they are protected by the same checksum. A number of devices offer block level dedup, either as an option or as part of their inner workings. However when you store three identical blocks on them and the devices does block level dedup internally, the device may just deduplicated your redundant metadata to a block stored just once that is stored on the non-voilatile storage. When this block is corrupted, you have essentially three corrupted copies. Three hit with one bullet. This is indeed an interesting problem: A device doing deduplication doesn't know if a block is important or just a datablock. This is the reason why I like deduplication like it's done in ZFS. It's an integrated part and so important parts don't get deduplicated away. A disk accessed by a block level interface doesn't know anything about the importance of a block. A metadata block is nothing different to it's inner mechanism than a normal data block because there is no way to tell that this is important and that those redundancies aren't allowed to fall prey to some clever deduplication mechanism. Robin talks about this in regard of the Sandforce disk controllers who use a kind of dedup to reduce some of the nasty effects of writing data to flash, but the problem is much broader. However this is relevant whenever you are using a device with block level deduplication. It's just the point that you have to activate it for most implementation by command, whereas certain devices do this by default or by design and you don't know about it. However I'm not perfectly sure about that ? given that storage administration and server administration are often different groups with different business objectives I would ask your storage guys if they have activated dedup without telling somebody elase on their boxes in order to speak less often with the storage sales rep. The problem is even more interesting with ZFS. You may use ditto blocks to protect important data to store multiple copies of data in the pool to increase redundancy, even when your pool just consists out of one disk or just a striped set of disk. However when your device is doing dedup internally it may remove your redundancy before it hits the nonvolatile storage. You've won nothing. Just spend your disk quota on the the LUNs in the SAN and you make your disk admin happy because of the good dedup ratio However you can just fall in this specific "deduped ditto block"trap when your pool just consists out of a single device, because ZFS writes ditto blocks on different disks, when there is more than just one disk. Yet another reason why you should spend some extra-thought when putting your zpool on a single LUN, especially when the LUN is sliced and dices out of a large heap of storage devices by a storage controller. However I have one problem with the articles and their specific mention of ZFS: You can just hit by this problem when you are using the deduplicating device for the pool. However in the specifically mentioned case of SSD this isn't the usecase. Most implementations of SSD in conjunction with ZFS are hybrid storage pools and so rotating rust disk is used as pool and SSD are used as L2ARC/sZIL. And there it simply doesn't matter: When you really have to resort to the sZIL (your system went down, it doesn't matter of one block or several blocks are corrupt, you have to fail back to the last known good transaction group the device. On the other side, when a block in L2ARC is corrupt, you simply read it from the pool and in HSP implementations this is the already mentioned rust. In conjunction with ZFS this is more interesting when using a storage array, that is capable to do dedup and where you use LUNs for your pool. However as mentioned before, on those devices it's a user made decision to do so, and so it's less probable that you deduplicating your redundancies. Other filesystems lacking acapability similar to hybrid storage pools are more "haunted" by this problem of SSD using dedup-like mechanisms internally, because those filesystem really store the data on the the SSD instead of using it just as accelerating devices. However at the end Robin is correct: It's jet another point why protecting your data by creating redundancies by dispersing it several disks (by mirror or parity RAIDs) is really important. No dedup mechanism inside a device can dedup away your redundancy when you write it to a totally different and indepenent device.

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• WPF Animation FPS vs. CPU usage - Am I expecting too much?

  - by Cory Charlton

  Working on a screen saver for my wife, http://cchearts.codeplex.com/, and while I've been able to improve FPS on lower end machines (switch from Path to StreamGeometry, use DrawingVisual instead of UserControl, etc) the CPU usage still seems very high. Here's some numbers I ran from a few 5 minute sampling periods: ~60FPS 35% average CPU on Core 2 Duo T7500 @ 2.2GHz, 3GB ram, NVIDIA Quadro NVS 140M (128MB), Vista [My dev laptop] ~40FPS 50% average CPU on Pentium D @ 3.4GHz, 1.5GB ram, Standard VGA Graphics Adapter (unknown), 2003 Server [A crappy desktop] I can understand the lower frame rate and higher CPU usage on the crappy desktop but it still seems pretty high and 35% on my dev laptop seems high as well. I'd really like to analyze the application to get more details but I'm having issues there as well so I'm wondering if I'm doing something wrong (never profiled WPF before). WPF Performance Suite: Process Launch Error Unable to attach to process: CCHearts.exe Do you want to kill it? This error message occurs when I click cancel after attempting launch. If I don't click cancel it sits there idle, I guess waiting to attach. Performance Explorer: Could not launch C:\Projects2\CC.Hearts\CC.Hearts\bin\Debug (USEVISUAL)\CCHearts.exe. Previous attempt to profile the application finished unsuccessfully. Please restart the application. Output Window from Performance: Profiling started. Profiling process ID 5360 (CCHearts). Process ID 5360 has exited. Data written to C:\Projects2\CC.Hearts\CCHearts100608.vsp. Profiling finished. PRF0025: No data was collected. Profiling complete. So I'm stuck wanting to improve performance but have no concrete way to determine where the bottleneck is. Have been relatively successful throwing darts at this point but I'm beyond that now :) PS: Screensaver is hosted at CodePlex if you want to look at the source and missed the link above. Edit: My RenderOptions darts... // NOTE: Grasping at straws here ;-) RenderOptions.SetBitmapScalingMode(newHeart, BitmapScalingMode.LowQuality); RenderOptions.SetCachingHint(newHeart, CachingHint.Cache); RenderOptions.SetEdgeMode(newHeart, EdgeMode.Aliased); I threw those a little while back and didn't see much difference (not sure if the bitmap scaling even comes into play). Really wish I could get profiling working to know where I should try to optimize. For now I assume there is some overhead in creating a new HeartVisual and the DrawingVisual contained inside. Maybe if I reset and reused the hearts (tossed them in a queue once they completed or something) I'd see an improvement. Shrug Throwing darts while blindfolder is always fun.

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• Long-running ASP.NET tasks

  - by John Leidegren

  I know there's a bunch of APIs out there that do this, but I also know that the hosting environment (being ASP.NET) puts restrictions on what you can reliably do in a separate thread. I could be completely wrong, so please correct me if I am, this is however what I think I know. A request typically timeouts after 120 seconds (this is configurable) but eventually the ASP.NET runtime will kill a request that's taking too long to complete. The hosting environment, typically IIS, employs process recycling and can at any point decide to recycle your app. When this happens all threads are aborted and the app restarts. I'm however not sure how aggressive it is, it would be kind of stupid to assume that it would abort a normal ongoing HTTP request but I would expect it to abort a thread because it doesn't know anything about the unit of work of a thread. If you had to create a programming model that easily and reliably and theoretically put a long running task, that would have to run for days, how would you accomplish this from within an ASP.NET application? The following are my thoughts on the issue: I've been thinking a long the line of hosting a WCF service in a win32 service. And talk to the service through WCF. This is however not very practical, because the only reason I would choose to do so, is to send tasks (units of work) from several different web apps. I'd then eventually ask the service for status updates and act accordingly. My biggest concern with this is that it would NOT be a particular great experience if I had to deploy every task to the service for it to be able to execute some instructions. There's also this issue of input, how would I feed this service with data if I had a large data set and needed to chew through it? What I typically do right now is this SELECT TOP 10 * FROM WorkItem WITH (ROWLOCK, UPDLOCK, READPAST) WHERE WorkCompleted IS NULL It allows me to use a SQL Server database as a work queue and periodically poll the database with this query for work. If the work item completed with success, I mark it as done and proceed until there's nothing more to do. What I don't like is that I could theoretically be interrupted at any point and if I'm in-between success and marking it as done, I could end up processing the same work item twice. I might be a bit paranoid and this might be all fine but as I understand it there's no guarantee that that won't happen... I know there's been similar questions on SO before but non really answers with a definitive answer. This is a really common thing, yet the ASP.NET hosting environment is ill equipped to handle long-running work. Please share your thoughts.

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• iOS static Framework crash when animating view

  - by user1439216

  I'm encountering a difficult to debug issue with a static library project when attempting to animate a view. It works fine when debugging (and even when debugging in the release configuration), but throws an error archived as a release: Exception Type: EXC_CRASH (SIGSYS) Exception Codes: 0x00000000, 0x00000000 Crashed Thread: 0 Thread 0 name: Dispatch queue: com.apple.main-thread Thread 0 Crashed: 0 TestApp 0x000d04fc 0x91000 + 259324 1 UIKit 0x336d777e +[UIView(UIViewAnimationWithBlocks) animateWithDuration:animations:] + 42 2 TestApp 0x000d04de 0x91000 + 259294 3 TestApp 0x000d0678 0x91000 + 259704 4 Foundation 0x355f04f8 __57-[NSNotificationCenter addObserver:selector:name:object:]_block_invoke_0 + 12 5 CoreFoundation 0x35aae540 ___CFXNotificationPost_block_invoke_0 + 64 6 CoreFoundation 0x35a3a090 _CFXNotificationPost + 1400 7 Foundation 0x355643e4 -[NSNotificationCenter postNotificationName:object:userInfo:] + 60 8 UIKit 0x33599112 -[UIInputViewTransition postNotificationsForTransitionStart] + 846 9 UIKit 0x335988cc -[UIPeripheralHost(UIKitInternal) executeTransition:] + 880 10 UIKit 0x3351bb8c -[UIPeripheralHost(UIKitInternal) setInputViews:animationStyle:] + 304 11 UIKit 0x3351b260 -[UIPeripheralHost(UIKitInternal) _reloadInputViewsForResponder:] + 952 12 UIKit 0x3351ae54 -[UIResponder(UIResponderInputViewAdditions) reloadInputViews] + 160 13 UIKit 0x3351a990 -[UIResponder becomeFirstResponder] + 452 14 UIKit 0x336194a0 -[UITextInteractionAssistant setFirstResponderIfNecessary] + 168 15 UIKit 0x33618d6a -[UITextInteractionAssistant oneFingerTap:] + 1602 16 UIKit 0x33618630 _UIGestureRecognizerSendActions + 100 17 UIKit 0x335a8d5e -[UIGestureRecognizer _updateGestureWithEvent:] + 298 18 UIKit 0x337d9472 ___UIGestureRecognizerUpdate_block_invoke_0541 + 42 19 UIKit 0x33524f4e _UIGestureRecognizerApplyBlocksToArray + 170 20 UIKit 0x33523a9c _UIGestureRecognizerUpdate + 892 21 UIKit 0x335307e2 _UIGestureRecognizerUpdateGesturesFromSendEvent + 22 22 UIKit 0x33530620 -[UIWindow _sendGesturesForEvent:] + 768 23 UIKit 0x335301ee -[UIWindow sendEvent:] + 82 24 UIKit 0x3351668e -[UIApplication sendEvent:] + 350 25 UIKit 0x33515f34 _UIApplicationHandleEvent + 5820 26 GraphicsServices 0x376d5224 PurpleEventCallback + 876 27 CoreFoundation 0x35ab651c __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 32 28 CoreFoundation 0x35ab64be __CFRunLoopDoSource1 + 134 29 CoreFoundation 0x35ab530c __CFRunLoopRun + 1364 30 CoreFoundation 0x35a3849e CFRunLoopRunSpecific + 294 31 CoreFoundation 0x35a38366 CFRunLoopRunInMode + 98 32 GraphicsServices 0x376d4432 GSEventRunModal + 130 33 UIKit 0x33544cce UIApplicationMain + 1074 Thread 0 crashed with ARM Thread State: r0: 0x0000004e r1: 0x000d04f8 r2: 0x338fed47 r3: 0x3f523340 r4: 0x00000000 r5: 0x2fe8da00 r6: 0x00000001 r7: 0x2fe8d9d0 r8: 0x3f54cad0 r9: 0x00000000 r10: 0x3fd00000 r11: 0x3f523310 ip: 0x3f497048 sp: 0x2fe8d988 lr: 0x33539a41 pc: 0x000d04fc cpsr: 0x60000010 To give some background info: The static library is part of an 'iOS fake-framework', built using the templates from here: https://github.com/kstenerud/iOS-Universal-Framework The framework presents a registration UI as a modal view on top of whatever the client application is doing at the time. It pushes these views using a handle to a UIViewController provided by the client application. It doesn't do anything special, but here's the animation code: -(void)keyboardWillShowNotification:(NSNotification *)notification { double animationDuration = [[[notification userInfo] objectForKey:UIKeyboardAnimationDurationUserInfoKey] doubleValue]; dispatch_async(dispatch_get_main_queue(), ^(void) { [self animateViewsToState:kUMAnimationStateKeyboardVisible forIdiom:[UIDevice currentDevice].userInterfaceIdiom forDuration:animationDuration]; }); } -(void)animateViewsToState:(kUMAnimationState)state forIdiom:(UIUserInterfaceIdiom)idiom forDuration:(double)duration { float fieldOffset; if (idiom == UIUserInterfaceIdiomPhone) { if (state == kUMAnimationStateKeyboardVisible) { fieldOffset = -KEYBOARD_HEIGHT_IPHONE_PORTRAIT; } else { fieldOffset = KEYBOARD_HEIGHT_IPHONE_PORTRAIT; } } else { if (state == kUMAnimationStateKeyboardVisible) { fieldOffset = -IPAD_FIELD_OFFSET; } else { fieldOffset = IPAD_FIELD_OFFSET; } } [UIView animateWithDuration:duration animations:^(void) { mUserNameField.frame = CGRectOffset(mUserNameField.frame, 0, fieldOffset); mUserPasswordField.frame = CGRectOffset(mUserPasswordField.frame, 0, fieldOffset); }]; } Further printf-style debugging shows that it crashes whenever I do anything much with UIKit - specifically, it crashes when I replace -animateViewsToState with: if (0 == UIUserInterfaceIdiomPhone) { NSLog(@""); } and [[[[UIAlertView alloc] initWithTitle:@"test" message:@"123" delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil] autorelease] show]; To me, this sounds like a linker problem, but I don't understand how such problems would only manifest here, and not beforehand. Any help would be greatly appreciated.

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• Zend Framework + Uplodify Flash Uploader Troubles

  - by Richard Knop

  I've been trying to get the Uploadify flash uploader (www.uploadify.com) to work with Zend Framework, with no success so far. I have placed all Uploadify files under /public/flash-uploader directory. In the controller I include all required files and libraries like this: $this->view->headScript()->appendFile('/js/jquery-1.3.2.min.js'); $this->view->headLink()->appendStylesheet('/flash-uploader/css/default.css'); $this->view->headLink()->appendStylesheet('/flash-uploader/css/uploadify.css'); $this->view->headScript()->appendFile('/flash-uploader/scripts/swfobject.js'); $this->view->headScript()->appendFile('/flash-uploader/scripts/jquery.uploadify.v2.1.0.min.js'); And then I activate the plugin like this (#photo is id of the input file field): $(document).ready(function() { $("#photo").uploadify({ 'uploader' : '/flash-uploader/scripts/uploadify.swf', 'script' : 'my-account/flash-upload', 'cancelImg' : '/flash-uploader/cancel.png', 'folder' : 'uploads/tmp', 'queueID' : 'fileQueue', 'auto' : true, 'multi' : true, 'sizeLimit' : 2097152 }); }); As you can see I am targeting the my-account/flash-upload script as a backend processing (my-account is a controller, flash-upload is an action). My form markup looks like this: <form enctype="multipart/form-data" method="post" action="/my-account/upload-public-photo"><ol> <li><label for="photo" class="optional">File Queue<div id="fileQueue"></div></label> <input type="hidden" name="MAX_FILE_SIZE" value="31457280" id="MAX_FILE_SIZE" /> <input type="file" name="photo" id="photo" class="input-file" /></li> <li><div class="button"> <input type="submit" name="upload_public_photo" id="upload_public_photo" value="Save" class="input-submit" /></div></li></ol></form> And yet it's not working. The browse button doesn't even show up as in the demo page, I get only a regular input file field. Any ideas where could the problem be? I've already been staring into the code for hours and I cannot see any mistake anywhere and I'm starting to be exhausted after going through the same 30 lines of code 30 times in a row.

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• JBOSS 7.1 started hanging after 6 months of deployment

  - by PVR

  My application is been live from 6 months. The application is host on jboss 7.1 server. From last few days I am finding numerous problem of hanging of jboss server. Though I restart the jboss server again, it does not invoke. I need to restart the server machine itself. Can anyone please let me know what could be the cause of these problems and the workable resolutions or any suggestion ? Kindly dont degrade the question as I am facing a lot problems due to this hanging issue. Also for the information, the application is based on Java, GWT, Hibernate 3. Please find the standalone.xml file in case if it helps. <extensions> <extension module="org.jboss.as.clustering.infinispan"/> <extension module="org.jboss.as.configadmin"/> <extension module="org.jboss.as.connector"/> <extension module="org.jboss.as.deployment-scanner"/> <extension module="org.jboss.as.ee"/> <extension module="org.jboss.as.ejb3"/> <extension module="org.jboss.as.jaxrs"/> <extension module="org.jboss.as.jdr"/> <extension module="org.jboss.as.jmx"/> <extension module="org.jboss.as.jpa"/> <extension module="org.jboss.as.logging"/> <extension module="org.jboss.as.mail"/> <extension module="org.jboss.as.naming"/> <extension module="org.jboss.as.osgi"/> <extension module="org.jboss.as.pojo"/> <extension module="org.jboss.as.remoting"/> <extension module="org.jboss.as.sar"/> <extension module="org.jboss.as.security"/> <extension module="org.jboss.as.threads"/> <extension module="org.jboss.as.transactions"/> <extension module="org.jboss.as.web"/> <extension module="org.jboss.as.webservices"/> <extension module="org.jboss.as.weld"/> </extensions> <system-properties> <property name="org.apache.coyote.http11.Http11Protocol.COMPRESSION" value="on"/> <property name="org.apache.coyote.http11.Http11Protocol.COMPRESSION_MIME_TYPES" value="text/javascript,text/css,text/html,text/xml,text/json"/> </system-properties> <management> <security-realms> <security-realm name="ManagementRealm"> <authentication> <properties path="mgmt-users.properties" relative-to="jboss.server.config.dir"/> </authentication> </security-realm> <security-realm name="ApplicationRealm"> <authentication> <properties path="application-users.properties" relative-to="jboss.server.config.dir"/> </authentication> </security-realm> </security-realms> <management-interfaces> <native-interface security-realm="ManagementRealm"> <socket-binding native="management-native"/> </native-interface> <http-interface security-realm="ManagementRealm"> <socket-binding http="management-http"/> </http-interface> </management-interfaces> </management> <profile> <subsystem xmlns="urn:jboss:domain:logging:1.1"> <console-handler name="CONSOLE"> <level name="INFO"/> <formatter> <pattern-formatter pattern="%d{HH:mm:ss,SSS} %-5p [%c] (%t) %s%E%n"/> </formatter> </console-handler> <periodic-rotating-file-handler name="FILE"> <formatter> <pattern-formatter pattern="%d{HH:mm:ss,SSS} %-5p [%c] (%t) %s%E%n"/> </formatter> <file relative-to="jboss.server.log.dir" path="server.log"/> <suffix value=".yyyy-MM-dd"/> <append value="true"/> </periodic-rotating-file-handler> <logger category="com.arjuna"> <level name="WARN"/> </logger> <logger category="org.apache.tomcat.util.modeler"> <level name="WARN"/> </logger> <logger category="sun.rmi"> <level name="WARN"/> </logger> <logger category="jacorb"> <level name="WARN"/> </logger> <logger category="jacorb.config"> <level name="ERROR"/> </logger> <root-logger> <level name="INFO"/> <handlers> <handler name="CONSOLE"/> <handler name="FILE"/> </handlers> </root-logger> </subsystem> <subsystem xmlns="urn:jboss:domain:configadmin:1.0"/> <subsystem xmlns="urn:jboss:domain:datasources:1.0"> <datasources> <datasource jndi-name="java:jboss/datasources/ExampleDS" pool-name="ExampleDS" enabled="true" use-java-context="true"> <connection-url>jdbc:h2:mem:test;DB_CLOSE_DELAY=-1</connection-url> <driver>h2</driver> <security> <user-name>sa</user-name> <password>sa</password> </security> </datasource> <drivers> <driver name="h2" module="com.h2database.h2"> <xa-datasource-class>org.h2.jdbcx.JdbcDataSource</xa-datasource-class> </driver> </drivers> </datasources> </subsystem> <subsystem xmlns="urn:jboss:domain:deployment-scanner:1.1"> <deployment-scanner path="deployments" relative-to="jboss.server.base.dir" scan-interval="5000"/> </subsystem> <subsystem xmlns="urn:jboss:domain:ee:1.0"/> <subsystem xmlns="urn:jboss:domain:ejb3:1.2"> <session-bean> <stateless> <bean-instance-pool-ref pool-name="slsb-strict-max-pool"/> </stateless> <stateful default-access-timeout="5000" cache-ref="simple"/> <singleton default-access-timeout="5000"/> </session-bean> <pools> <bean-instance-pools> <strict-max-pool name="slsb-strict-max-pool" max-pool-size="20" instance-acquisition-timeout="5" instance-acquisition-timeout-unit="MINUTES"/> <strict-max-pool name="mdb-strict-max-pool" max-pool-size="20" instance-acquisition-timeout="5" instance-acquisition-timeout-unit="MINUTES"/> </bean-instance-pools> </pools> <caches> <cache name="simple" aliases="NoPassivationCache"/> <cache name="passivating" passivation-store-ref="file" aliases="SimpleStatefulCache"/> </caches> <passivation-stores> <file-passivation-store name="file"/> </passivation-stores> <async thread-pool-name="default"/> <timer-service thread-pool-name="default"> <data-store path="timer-service-data" relative-to="jboss.server.data.dir"/> </timer-service> <remote connector-ref="remoting-connector" thread-pool-name="default"/> <thread-pools> <thread-pool name="default"> <max-threads count="10"/> <keepalive-time time="100" unit="milliseconds"/> </thread-pool> </thread-pools> </subsystem> <subsystem xmlns="urn:jboss:domain:infinispan:1.2" default-cache-container="hibernate"> <cache-container name="hibernate" default-cache="local-query"> <local-cache name="entity"> <transaction mode="NON_XA"/> <eviction strategy="LRU" max-entries="10000"/> <expiration max-idle="100000"/> </local-cache> <local-cache name="local-query"> <transaction mode="NONE"/> <eviction strategy="LRU" max-entries="10000"/> <expiration max-idle="100000"/> </local-cache> <local-cache name="timestamps"> <transaction mode="NONE"/> <eviction strategy="NONE"/> </local-cache> </cache-container> </subsystem> <subsystem xmlns="urn:jboss:domain:jaxrs:1.0"/> <subsystem xmlns="urn:jboss:domain:jca:1.1"> <archive-validation enabled="true" fail-on-error="true" fail-on-warn="false"/> <bean-validation enabled="true"/> <default-workmanager> <short-running-threads> <core-threads count="50"/> <queue-length count="50"/> <max-threads count="50"/> <keepalive-time time="10" unit="seconds"/> </short-running-threads> <long-running-threads> <core-threads count="50"/> <queue-length count="50"/> <max-threads count="50"/> <keepalive-time time="100" unit="seconds"/> </long-running-threads> </default-workmanager> <cached-connection-manager/> </subsystem> <subsystem xmlns="urn:jboss:domain:jdr:1.0"/> <subsystem xmlns="urn:jboss:domain:jmx:1.1"> <show-model value="true"/> <remoting-connector/> </subsystem> <subsystem xmlns="urn:jboss:domain:jpa:1.0"> <jpa default-datasource=""/> </subsystem> <subsystem xmlns="urn:jboss:domain:mail:1.0"> <mail-session jndi-name="java:jboss/mail/Default"> <smtp-server outbound-socket-binding-ref="mail-smtp"/> </mail-session> </subsystem> <subsystem xmlns="urn:jboss:domain:naming:1.1"/> <subsystem xmlns="urn:jboss:domain:osgi:1.2" activation="lazy"> <properties> <property name="org.osgi.framework.startlevel.beginning"> 1 </property> </properties> <capabilities> <capability name="javax.servlet.api:v25"/> <capability name="javax.transaction.api"/> <capability name="org.apache.felix.log" startlevel="1"/> <capability name="org.jboss.osgi.logging" startlevel="1"/> <capability name="org.apache.felix.configadmin" startlevel="1"/> <capability name="org.jboss.as.osgi.configadmin" startlevel="1"/> </capabilities> </subsystem> <subsystem xmlns="urn:jboss:domain:pojo:1.0"/> <subsystem xmlns="urn:jboss:domain:remoting:1.1"> <connector name="remoting-connector" socket-binding="remoting" security-realm="ApplicationRealm"/> </subsystem> <subsystem xmlns="urn:jboss:domain:resource-adapters:1.0"/> <subsystem xmlns="urn:jboss:domain:sar:1.0"/> <subsystem xmlns="urn:jboss:domain:security:1.1"> <security-domains> <security-domain name="other" cache-type="default"> <authentication> <login-module code="Remoting" flag="optional"> <module-option name="password-stacking" value="useFirstPass"/> </login-module> <login-module code="RealmUsersRoles" flag="required"> <module-option name="usersProperties" value="${jboss.server.config.dir}/application-users.properties"/> <module-option name="rolesProperties" value="${jboss.server.config.dir}/application-roles.properties"/> <module-option name="realm" value="ApplicationRealm"/> <module-option name="password-stacking" value="useFirstPass"/> </login-module> </authentication> </security-domain> <security-domain name="jboss-web-policy" cache-type="default"> <authorization> <policy-module code="Delegating" flag="required"/> </authorization> </security-domain> <security-domain name="jboss-ejb-policy" cache-type="default"> <authorization> <policy-module code="Delegating" flag="required"/> </authorization> </security-domain> </security-domains> </subsystem> <subsystem xmlns="urn:jboss:domain:threads:1.1"/> <subsystem xmlns="urn:jboss:domain:transactions:1.1"> <core-environment> <process-id> <uuid/> </process-id> </core-environment> <recovery-environment socket-binding="txn-recovery-environment" status-socket-binding="txn-status-manager"/> <coordinator-environment default-timeout="300"/> </subsystem> <subsystem xmlns="urn:jboss:domain:web:1.1" default-virtual-server="default-host" native="false"> <connector name="http" protocol="HTTP/1.1" scheme="http" socket-binding="http"/> <virtual-server name="default-host" enable-welcome-root="false"> <alias name="localhost"/> <alias name="nextenders.com"/> </virtual-server> </subsystem> <subsystem xmlns="urn:jboss:domain:webservices:1.1"> <modify-wsdl-address>true</modify-wsdl-address> <wsdl-host>${jboss.bind.address:127.0.0.1}</wsdl-host> <endpoint-config name="Standard-Endpoint-Config"/> <endpoint-config name="Recording-Endpoint-Config"> <pre-handler-chain name="recording-handlers" protocol-bindings="##SOAP11_HTTP ##SOAP11_HTTP_MTOM ##SOAP12_HTTP ##SOAP12_HTTP_MTOM"> <handler name="RecordingHandler" class="org.jboss.ws.common.invocation.RecordingServerHandler"/> </pre-handler-chain> </endpoint-config> </subsystem> <subsystem xmlns="urn:jboss:domain:weld:1.0"/> </profile> <interfaces> <interface name="management"> <inet-address value="${jboss.bind.address.management:127.0.0.1}"/> </interface> <interface name="public"> <inet-address value="${jboss.bind.address:127.0.0.1}"/> </interface> <interface name="unsecure"> <inet-address value="${jboss.bind.address.unsecure:127.0.0.1}"/> </interface> </interfaces> <socket-binding-group name="standard-sockets" default-interface="public" port-offset="${jboss.socket.binding.port-offset:0}"> <socket-binding name="management-native" interface="management" port="${jboss.management.native.port:9999}"/> <socket-binding name="management-http" interface="management" port="${jboss.management.http.port:9990}"/> <socket-binding name="management-https" interface="management" port="${jboss.management.https.port:9443}"/> <socket-binding name="ajp" port="8009"/> <socket-binding name="http" port="80"/> <socket-binding name="https" port="443"/> <socket-binding name="osgi-http" interface="management" port="8090"/> <socket-binding name="remoting" port="4447"/> <socket-binding name="txn-recovery-environment" port="4712"/> <socket-binding name="txn-status-manager" port="4713"/> <outbound-socket-binding name="mail-smtp"> <remote-destination host="localhost" port="25"/> </outbound-socket-binding> </socket-binding-group>

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• VSTS test deployment and invalid assembly culture

  - by Merlyn Morgan-Graham

  I have a DLL that I'm testing, which links to a DLL that has what I think is an invalid value for AssemblyCulture. The value is "Neutral" (notice the upper-case "N"), whereas the DLL I'm testing, and every other DLL in my project, has a value of "neutral" (because they specify AssemblyCulture("")). When I try to deploy the DLL that links to the problem DLL, I get this error in VSTS: Failed to queue test run '...': Culture is not supported. Parameter name: name Neutral is an invalid culture identifier. <Exception>System.Globalization.CultureNotFoundException: Culture is not supported. Parameter name: name Neutral is an invalid culture identifier. at System.Globalization.CultureInfo..ctor(String name, Boolean useUserOverride) at System.Globalization.CultureInfo..ctor(String name) at System.Reflection.RuntimeAssembly.GetReferencedAssemblies(RuntimeAssembly assembly) at System.Reflection.RuntimeAssembly.GetReferencedAssemblies() at Microsoft.VisualStudio.TestTools.Utility.AssemblyLoadWorker.ProcessChildren(Assembly assembly) at Microsoft.VisualStudio.TestTools.Utility.AssemblyLoadWorker.GetDependentAssemblies(String path) at Microsoft.VisualStudio.TestTools.Utility.AssemblyLoadWorker.GetDependentAssemblies(String path) at Microsoft.VisualStudio.TestTools.Utility.AssemblyLoadStrategy.GetDependentAssemblies(String path) at Microsoft.VisualStudio.TestTools.Utility.AssemblyHelper.GetDependentAssemblies(String path, DependentAssemblyOptions options, String configFile) at Microsoft.VisualStudio.TestTools.TestManagement.DeploymentManager.GetDependencies(String master, String configFile, TestRunConfiguration runConfig, DeploymentItemOrigin dependencyOrigin, List`1 dependencyDeploymentItems, Dictionary`2 missingDependentAssemblies) at Microsoft.VisualStudio.TestTools.TestManagement.DeploymentManager.DoDeployment(TestRun run, FileCopyService fileCopyService) at Microsoft.VisualStudio.TestTools.TestManagement.ControllerProxy.SetupTestRun(TestRun run, Boolean isNewTestRun, FileCopyService fileCopyService, DeploymentManager deploymentManager) at Microsoft.VisualStudio.TestTools.TestManagement.ControllerProxy.SetupRunAndListener(TestRun run, FileCopyService fileCopyService, DeploymentManager deploymentManager) at Microsoft.VisualStudio.TestTools.TestManagement.ControllerProxy.QueueTestRunWorker(Object state)</Exception> Even if I don't link to the DLL (in my VSTS wrapper test, or in the NUnit test), as soon as I add it in my GenericTest file (I'm wrapping NUnit tests), I get that exception. We don't have the source for the problem DLL, and it is also code signed, so I can't solve this by recompiling. Is there a way to skip deploying the dependencies of a DLL DeploymentItem, to fix or disable the culture check, or to work around this by convoluted means (maybe somehow embed the assembly)? Is there a way to override the value for the culture, short of hacking the DLL (and removing code signing so the hack works)? Maybe with an external manifest? Any correct solution must work without weird changes to production code. We can't deploy a hacked DLL, for example. It also must allow the DLL to be instrumented for code coverage. Additional note: I do get a linker warning when compiling the DLL under test that links to the problem DLL, but this hasn't broken anything but VSTS, and multiple versions have shipped.

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• Handling Exceptions for ThreadPoolExecutor

  - by HonorGod

  I have the following code snippet that basically scans through the list of task that needs to be executed and each task is then given to the executor for execution. The JobExecutor intern creates another executor (for doing db stuff...reading and writing data to queue) and completes the task. JobExecutor returns a Future for the tasks submitted. When one of the task fails, I want to gracefully interrupt all the threads and shutdown the executor by catching all the exceptions. What changes do I need to do? public class DataMovingClass { private static final AtomicInteger uniqueId = new AtomicInteger(0); private static final ThreadLocal<Integer> uniqueNumber = new IDGenerator(); ThreadPoolExecutor threadPoolExecutor = null ; private List<Source> sources = new ArrayList<Source>(); private static class IDGenerator extends ThreadLocal<Integer> { @Override public Integer get() { return uniqueId.incrementAndGet(); } } public void init(){ // load sources list } public boolean execute() { boolean succcess = true ; threadPoolExecutor = new ThreadPoolExecutor(10,10, 10, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(1024), new ThreadFactory() { public Thread newThread(Runnable r) { Thread t = new Thread(r); t.setName("DataMigration-" + uniqueNumber.get()); return t; }// End method }, new ThreadPoolExecutor.CallerRunsPolicy()); List<Future<Boolean>> result = new ArrayList<Future<Boolean>>(); for (Source source : sources) { result.add(threadPoolExecutor.submit(new JobExecutor(source))); } for (Future<Boolean> jobDone : result) { try { if (!jobDone.get(100000, TimeUnit.SECONDS) && success) { // in case of successful DbWriterClass, we don't need to change // it. success = false; } } catch (Exception ex) { // handle exceptions } } } public class JobExecutor implements Callable<Boolean> { private ThreadPoolExecutor threadPoolExecutor ; Source jobSource ; public SourceJobExecutor(Source source) { this.jobSource = source; threadPoolExecutor = new ThreadPoolExecutor(10,10,10, TimeUnit.SECONDS, new ArrayBlockingQueue<Runnable>(1024), new ThreadFactory() { public Thread newThread(Runnable r) { Thread t = new Thread(r); t.setName("Job Executor-" + uniqueNumber.get()); return t; }// End method }, new ThreadPoolExecutor.CallerRunsPolicy()); } public Boolean call() throws Exception { boolean status = true ; System.out.println("Starting Job = " + jobSource.getName()); try { // do the specified task ; }catch (InterruptedException intrEx) { logger.warn("InterruptedException", intrEx); status = false ; } catch(Exception e) { logger.fatal("Exception occurred while executing task "+jobSource.getName(),e); status = false ; } System.out.println("Ending Job = " + jobSource.getName()); return status ; } } }

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• How to efficiently save changes made in UI/main thread with Core Data?

  - by Jaanus

  So, there have been several posts here about importing and saving data from an external data source into Core Data. Apple documents a reasonable pattern for this: "import and save on background thread, merge saved objects to main thread." All fine and good. I have a related but different problem: the user is modifying data in the UI and main thread, and thus modifies state of some objects in the managed object context (MOC). I would like to save these changes from time to time. What is a good way to do that? Now, you could say that I could do the same: create a background thread with its own MOC and pass the changed objectID-s there. The catch-22 for me with this is that an object's ID changes when it is saved, and I cannot guarantee the order of things happening. I may end up passing a different objectID into the background thread for the same object, based on whether the object has been previously saved or not, and I don't know if Core Data can resolve this and see that different objectID-s are pointing to the same object and not create duplicates for me. (I could test this, but I'm lazywebbing with this question first.) One thought I had: I could always do MOC saves on a background thread, and queue them up with operationqueue, so that there is always only one save in progress. I would not create a new MOC, I would just use the same MOC as in main thread. Now, this is not thread safe and when someone modifies the MOC in main thread while it is being saved in background thread, the results will probably be catastrophic. But, minus the thread safety, you can see what kind of solution I'd wish for. To be clear, the problem I need to fix is that if I just do the save in main thread, it blocks the UI for an unacceptably long period of time, I want to move the save to background thread. So, questions: what about the reasoning of an object ID changing during saving, and Core Data being able to resolve them to the same object? Would this be the right way of addressing this problem? any other good ways of doing this?

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• ObjectDisposedException from core .NET code

  - by John

  I'm having this issue with a live app. (Unfortunately this is post-mortem debugging - I only have this stack trace. I've never seen this personally, nor am I able to reproduce). I get this Exception: message=Cannot access a disposed object. Object name: 'Button'. exceptionMessage=Cannot access a disposed object. Object name: 'Button'. exceptionDetails=System.ObjectDisposedException: Cannot access a disposed object. Object name: 'Button'. at System.Windows.Forms.Control.CreateHandle() at System.Windows.Forms.Control.get_Handle() at System.Windows.Forms.Control.PointToScreen(Point p) at System.Windows.Forms.Button.OnMouseUp(MouseEventArgs mevent) at System.Windows.Forms.Control.WmMouseUp(Message& m, MouseButtons button, Int32 clicks) at System.Windows.Forms.Control.WndProc(Message& m) at System.Windows.Forms.ButtonBase.WndProc(Message& m) at System.Windows.Forms.Button.WndProc(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m) at System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m) at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam) exceptionSource=System.Windows.Forms exceptionTargetSite=Void CreateHandle() It looks like a mouse event is arriving at a form after the form has been disposed. Note there is none of my code in this stack trace. The only weird (?) thing I'm doing, is that I do tend to Dispose() Forms quite aggressively when I use them with ShowModal() (see "Aside" below). But I only do this after ShowModal() has returned (that should be safe right)? I think I read that events might be queued up in the event queue, but I can't believe this would be the problem. I mean surely the framework must be tolerant to old messages? I can well imagine that under stress messages might back-log and surely the window might go away at any time? Any ideas? If you could even suggest ways of reproducing, that might be useful. John Aside: TBH I've never quite understood whether calling Dispose() after Form.ShowDialog() is strictly necessary - the MSDN docs for ShowDialog() are to my mind a bit ambiguous.

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• WCF Duplex Interaction with Web Server

  - by Mark Struzinski

  Here is my scenario, and it is causing us a considerable amount of grief at the moment: We have a vendor web service which provides base level telephony functionality. This service has a SOAP api, which we are leveraging to build up a custom UI that is integrated into our in house web apps. The api functions on 2 levels. You make standard client calls into the service to initiate actions, such as Login, Place Call, Hang Up, etc. On a different thread, the service sends events back to the client to alert the user of things that are occurring on the system (agent successfully logged in, call was disconnected, etc). I implemented a WCF service to sit between the web server and the vendor service. This WCF service operates in duplex mode, establishing a 2 way connection with the web server. The web server makes outbound calls to the WCF service, which routes them to the vendor's web service. Events are received back to the WCF service, which passes them onto the web server via a callback channel on the WCF client. As events are received on the web server, they are placed into a hash table with the user's name as the key, and a .NET queue as the value to hold the event. Each event is enqueued to the agent who owns it. On a 2 second interval, the web page polls the web server via an ajax request to get new events for the logged in user. It hits the hash table for the user key, dequeues any events that are present, and serializes them back up to the web page. From there, they are processed in order and appropriate messages are displayed to the user. This implementation performs well in a single user scenario. The second I put more than 1 user on the system, I start getting frequent timeouts with the following CommunicationException: A connection attempt failed because the connected party did not properly respond after a period of time, or established connection failed because connected host has failed to respond We are running Windows Server 2008 R2 both servers. Both the web app and WCF service are running on .NET 3.5. The WCF service is running under the net.tcp protocol in duplex mode. The web app is ASP.NET MVC 2. Has anyone dealt with anything like this scenario? Is there a more efficient way (or a widely accepted pattern) to implement this?

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• exc_bad_access on insertNewObjectForEntityForName:inManagedObjectContext

  - by matthewc

  I have a garbage collected Cocoa application built on 10.5 frameworks. In an NSOperation In a loop I am quickly creating hundreds of NSManagedObjects. Frequently the creation of those NSManagedObejcts will crash with a exc_bad_access error. for (offsetCount; offsetCount < [parsedData count]; offsetCount++) { NSManagedObject *child = [NSEntityDescription insertNewObjectForEntityForName:@"Thread" inManagedObjectContext:[self moc]]; Thumbnail *thumb = [Thumbnail insertInManagedObjectContext:[self moc]]; Image *image = [Image insertInManagedObjectContext:[self moc]]; ... } Thumbnail and Image are both subclasses of NSManagedObject generated with mogenerator. insertInManagedObjectContext: looks like NSParameterAssert(moc_); return [NSEntityDescription insertNewObjectForEntityForName:@"Thumbnail" inManagedObjectContext:moc_]; NSParameterAssert(moc_); return [NSEntityDescription insertNewObjectForEntityForName:@"Image" inManagedObjectContext:moc_]; The NSManagedObjectContext returned by [self moc] is created for the NSOperation with NSPersistentStoreCoordinator *coord = [(MyApp_AppDelegate *)[[NSApplication sharedApplication] delegate] persistentStoreCoordinator]; self.moc = [[NSManagedObjectContext alloc] init]; [self.moc setPersistentStoreCoordinator:coord]; [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(contextDidSave:) name:NSManagedObjectContextDidSaveNotification object:self.moc]; [self.moc setMergePolicy:NSMergeByPropertyObjectTrumpMergePolicy]; [self.moc setUndoManager:nil]; [self.moc setRetainsRegisteredObjects:YES]; moc is defined as (nonatomic, retain) and synthesized. As far as I can tell it, the persistent store and my appDelegate have no reason to be and are not being garbage collected. The stack trace looks like Thread 2 Crashed: Dispatch queue: com.apple.root.default-priority 0 libauto.dylib 0x00007fff82d63600 auto_zone_root_write_barrier + 688 1 libobjc.A.dylib 0x00007fff826f963b objc_assign_strongCast_gc + 59 2 com.apple.CoreFoundation 0x00007fff88677068 __CFBasicHashAddValue + 504 3 com.apple.CoreFoundation 0x00007fff88676d2f CFBasicHashAddValue + 191 4 com.apple.CoreData 0x00007fff82bdee5e -[NSManagedObjectContext(_NSInternalAdditions) _insertObjectWithGlobalID:globalID:] + 190 5 com.apple.CoreData 0x00007fff82bded24 -[NSManagedObjectContext insertObject:] + 148 6 com.apple.CoreData 0x00007fff82bbd75c -[NSManagedObject initWithEntity:insertIntoManagedObjectContext:] + 716 7 com.apple.CoreData 0x00007fff82bdf075 +[NSEntityDescription insertNewObjectForEntityForName:inManagedObjectContext:] + 101 8 com.yourcompany.MyApp 0x000000010002c7a7 +[_Thumbnail insertInManagedObjectContext:] + 256 (_Thumbnail.m:14) 9 com.yourcompany.MyApp 0x000000010002672d -[ThreadParse main] + 10345 (B4ChanThreadParse.m:174) 10 com.apple.Foundation 0x00007fff85ee807e -[__NSOperationInternal start] + 698 11 com.apple.Foundation 0x00007fff85ee7d23 ____startOperations_block_invoke_2 + 99 12 libSystem.B.dylib 0x00007fff812bece8 _dispatch_call_block_and_release + 15 13 libSystem.B.dylib 0x00007fff8129d279 _dispatch_worker_thread2 + 231 14 libSystem.B.dylib 0x00007fff8129cbb8 _pthread_wqthread + 353 15 libSystem.B.dylib 0x00007fff8129ca55 start_wqthread + 13 My app is crashing in other places with exc_bad_access but this is code that it happens most with. All of the stack traces look similar and have something to do with CFHash. Any help would be appreciated.

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• fetching rows from mysql table and displaying them as JGROWL notifications

  - by jeansymolanza

  hey guys, i am having problems implementing my php/mysql code into a jgrowl if you are familiar with jgrowl you will know it delivers notifications like Growl does for OS X i am trying to get it read all the records from my table but at the moment it is only displaying one record as a notification and it loops through it 4 times another problem is that if i have 5 rows in the table then jgrowl will only display 4 notifications are going to be viewed how do i get it to view all the records in the table as notifications and how do i display the total number of records (5) as notifications and account for the missing one at the moment thanking you guys in advance... God bless <script type="text/javascript"> // In case you don't have firebug... if (!window.console || !console.firebug) { var names = ["log", "debug", "info", "warn", "error", "assert", "dir", "dirxml", "group", "groupEnd", "time", "timeEnd", "count", "trace", "profile", "profileEnd"]; window.console = {}; for (var i = 0; i < names.length; ++i) window.console[names[i]] = function() {}; } (function($){ $(document).ready(function(){ // This specifies how many messages can be pooled out at any given time. // If there are more notifications raised then the pool, the others are // placed into queue and rendered after the other have disapeared. $.jGrowl.defaults.pool = 5; var i = 1; var y = 1; setInterval( function() { if ( i < <?php echo $totalRows_comment; ?> ) { <?php echo '$.jGrowl("'.$row_comment['comment'].'",'; ?> { sticky: true, log: function() { console.log("Creating message " + i + "..."); }, beforeOpen: function() { console.log("Rendering message " + y + "..."); y++; } }); } i++; } , 1000 ); }); })(jQuery); </script> <p> </span> <p>

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• Dealing with missing messages in JavaScript when using BOSH

  - by JamieD

  We recently went into private beta on our flagship product and had a small launch event. Unfortunately the venue had a terrible wireless connection and packets were being dropped left right and centre causing havoc with out system, basically it wasn't able to work at all! Luckily we were able to switch to a different network and rescue the demo. This highlighted something that I knew was already an issue but hadn't appreciated quite how much of an issue it could be. Our system relies heavily on BOSH and has a rather large JavaScript code base which now works rather well under good network conditions. However we need to make it work well under bad network conditions as well. Due to the way that XMPP works, a fire and forget system, it's not easy to tell if a message you sent, or were supposed to receive, was actually sent or received. For instance, we have an offer system, one user will send an offer to another over BOSH. When this message is received by the server a message is published to the offering users offers_sent PEP node and a similar message to the receiving users offers_received PEP node. While the sending user is able to tell if their offer was send (relatively) easily, if the notification to the receiving user is never received that user will never know it missed a message. A little about out JavaScript setup, it has 4 main layers: StropheJS An MVC framework for dealing with low level tasks and to build on top of An application layer which contains the app logic routes, controllers models etc. as well as a browser cache of the model data A UI layer that receives events and publishes events to and from the application layer One way to solve the missing messages issue would be to periodically check the PEP nodes for new data that the browser doesn't know about. If a new message was discovered the browsers cache would be invalidated and all new data would be requested from the server. I'm not sure this is the best way to go and it also doesn't cover all situations. We certainly don't want to get into the situation where we are sending messages to confirm the previous message was received at it's destination as this would double the network traffic. With the number of real time websites growing daily this is an issue that must have been encountered by other developers, it would be interesting to see how it's been solved by others. As far as I can see there are two situations in which messages go missing: On poor connections messages are not sent or received due to the packets being dropped Involving navigating between pages, a message is received by the browser but is not fully processed and stored in the local cache before the page is unloaded. Or a message is added to the send queue but never sent before the page is unloaded I suspect the hardest issue to solve will be number 2. Any thoughts on the subject would be much appreciated.

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• Agilent E4426B signal generator locks up during multiple GPIB *SAV operations

  - by aspiehler

  I have a test fixture with an Agilent E4426B RF signal generator connected to a PC via a National Instrument Ethernet-to-GPIB bridge. My software is attempting to sanitize the instrument by presetting it and then saving the current state to all of the memory locations writable via the standard SCPI command "*SAV x,y". The loop works to a point, but eventually the instrument responds with an error and continuously displays the "L" icon on the front display and a "Remote preset" message at the bottom. At that point it won't respond to any more remote commands and I have to either cycle power or press LOCAL, then PRESET at which point it takes about 3 minutes to finish presetting. At that point the "L" icon is still present and and the next GPIB command sent to the instrument causes it to report a -113 error (undefined header) in the instrument error queue. I fired up NI spy to see what was happening, and found that the error was happening at the same point in the loop - "*SAV 6,2" in this case. From NI Spy: Send (0, 0x0017, "*SAV 6,2", 8 (0x8), NLend (0,0x01)) Process ID: 0x00000520 Thread ID: 0x00000518 ibsta:0xc168 iberr: 6 ibcntl: 2(0x2) And here's the code from the instrument driver: int CHP_E4426b::Erase() { if ((m_StatusCode = Initialize()) != GPIB_SUCCESS) // basically just sends "*RST" return m_StatusCode; m_SaveState = "*SAV %d, %d"; for (int i=0; i < 10; i++) for (int j=0; j < 100; j++) { sprintf(m_CmdString, m_SaveState, j, i); if ((m_StatusCode = Send(m_CmdString, strlen(m_CmdString))) != GPIB_SUCCESS) return m_StatusCode; } return GPIB_SUCCESS; } I tried putting a small Sleep() delay (10-20 ms) at the end of the inner loop, and to my surprise it caused the error to show up earlier rather than later. 10 ms caused the loop to error out at 44,1 and 20 ms was even sooner. I've already eliminated faulty cabling or the instrument as the culprit. This same type of sequence works without any error on a higher end signal generator, so I'm tempted to chalk this up to a bug in the instrument's firmware.

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• Help with infrequent segmentation fault in accessing struct

  - by Sarah

  I'm having trouble debugging a segmentation fault. I'd appreciate tips on how to go about narrowing in on the problem. The error appears when an iterator tries to access an element of a struct Infection, defined as: struct Infection { public: explicit Infection( double it, double rt ) : infT( it ), recT( rt ) {} double infT; // infection start time double recT; // scheduled recovery time }; These structs are kept in a special structure, InfectionMap: typedef boost::unordered_multimap< int, Infection > InfectionMap; Every member of class Host has an InfectionMap carriage. Recovery times and associated host identifiers are kept in a priority queue. When a scheduled recovery event arises in the simulation for a particular strain s in a particular host, the program searches through carriage of that host to find the Infection whose recT matches the recovery time (double recoverTime). (For reasons that aren't worth going into, it's not as expedient for me to use recT as the key to InfectionMap; the strain s is more useful, and coinfections with the same strain are possible.) assert( carriage.size() > 0 ); pair<InfectionMap::iterator,InfectionMap::iterator> ret = carriage.equal_range( s ); InfectionMap::iterator it; for ( it = ret.first; it != ret.second; it++ ) { if ( ((*it).second).recT == recoverTime ) { // produces seg fault carriage.erase( it ); } } I get a "Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_INVALID_ADDRESS at address..." on the line specified above. The recoverTime is fine, and the assert(...) in the code is not tripped. As I said, this seg fault appears 'randomly' after thousands of successful recovery events. How would you go about figuring out what's going on? I'd love ideas about what could be wrong and how I can further investigate the problem.

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• Rails: AJAX Controller JS not firing...

  - by neezer

  I'm having an issue with one of my controller's AJAX functionality. Here's what I have: class PhotosController < ApplicationController # ... def create @photo = Photo.new(params[:photo]) @photo.image_content_type = MIME::Types.type_for(@photo.image_file_name).to_s @photo.image_width = Paperclip::Geometry.from_file(params[:photo][:image]).width.to_i @photo.image_height = Paperclip::Geometry.from_file(params[:photo][:image]).height.to_i @photo.save! respond_to do |format| format.js end end # ... end This is called through a POST request sent by this code: $(function() { // add photos link $('a.add-photos-link').colorbox({ overlayClose: false, onComplete: function() { wire_add_photo_modal(); } }); function wire_add_photo_modal() { <% session_key = ActionController::Base.session_options[:key] %> $('#upload_photo').uploadify({ uploader: '/swf/uploadify.swf', script: '/photos', cancelImg: '/images/buttons/cancel.png', buttonText: 'Upload Photo(s)', auto: true, queueID: 'queue', fileDataName: 'photo[image]', scriptData: { '<%= session_key %>': '<%= u cookies[session_key] %>', commit: 'Adding Photo', controller: 'photos', action: 'create', '_method': 'post', 'photo[gallery_id]': $('#gallery_id').val(), 'photo[user_id]': $('#user_id').val(), authenticity_token: encodeURIComponent('<%= u form_authenticity_token if protect_against_forgery? %>') }, multi: true }); } }); Finally, I have my response code in app/views/photos/create.js.erb: alert('photo added!'); My log file shows that the request was successful (the photo was successfully uploaded), and it even says that it rendered the create action, yet I never get the alert. My browser shows NO javascript errors. Here's the log AFTER a request from the above POST request is submitted: Processing PhotosController#create (for 127.0.0.1 at 2010-03-16 14:35:33) [POST] Parameters: {"Filename"=>"tumblr_kx74k06IuI1qzt6cxo1_400.jpg", "photo"=>{"user_id"=>"1", "image"=>#<File:/tmp/RackMultipart20100316-54303-7r2npu-0>}, "commit"=>"Adding Photo", "_edited_session"=>"edited", "folder"=>"/kakagiloon/", "authenticity_token"=>"edited", "action"=>"create", "_method"=>"post", "Upload"=>"Submit Query", "controller"=>"photos"} [paperclip] Saving attachments. [paperclip] saving /public/images/assets/kakagiloon/thumbnail/tumblr_kx74k06IuI1qzt6cxo1_400.jpg [paperclip] saving /public/images/assets/kakagiloon/profile/tumblr_kx74k06IuI1qzt6cxo1_400.jpg [paperclip] saving /public/images/assets/kakagiloon/original/tumblr_kx74k06IuI1qzt6cxo1_400.jpg Rendering photos/create Completed in 248ms (View: 1, DB: 6) | 200 OK [http://edited.local/photos] NOTE: I edited out all the SQL statements and I put "edited" in place of sensitive info. What gives? Why aren't I getting my alert();? Please let me know if you need anymore info to help me solve this issue! Thanks.

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• Twisted: why is it that passing a deferred callback to a deferred thread makes the thread blocking a

  - by surtyaarthoughts

  I unsuccessfully tried using txredis (the non blocking twisted api for redis) for a persisting message queue I'm trying to set up with a scrapy project I am working on. I found that although the client was not blocking, it became much slower than it could have been because what should have been one event in the reactor loop was split up into thousands of steps. So instead, I tried making use of redis-py (the regular blocking twisted api) and wrapping the call in a deferred thread. It works great, however I want to perform an inner deferred when I make a call to redis as I would like to set up connection pooling in attempts to speed things up further. Below is my interpretation of some sample code taken from the twisted docs for a deferred thread to illustrate my use case: #!/usr/bin/env python from twisted.internet import reactor,threads from twisted.internet.task import LoopingCall import time def main_loop(): print 'doing stuff in main loop.. do not block me!' def aBlockingRedisCall(): print 'doing lookup... this may take a while' time.sleep(10) return 'results from redis' def result(res): print res def main(): lc = LoopingCall(main_loop) lc.start(2) d = threads.deferToThread(aBlockingRedisCall) d.addCallback(result) reactor.run() if __name__=='__main__': main() And here is my alteration for connection pooling that makes the code in the deferred thread blocking : #!/usr/bin/env python from twisted.internet import reactor,defer from twisted.internet.task import LoopingCall import time def main_loop(): print 'doing stuff in main loop.. do not block me!' def aBlockingRedisCall(x): if x<5: #all connections are busy, try later print '%s is less than 5, get a redis client later' % x x+=1 d = defer.Deferred() d.addCallback(aBlockingRedisCall) reactor.callLater(1.0,d.callback,x) return d else: print 'got a redis client; doing lookup.. this may take a while' time.sleep(10) # this is now blocking.. any ideas? d = defer.Deferred() d.addCallback(gotFinalResult) d.callback(x) return d def gotFinalResult(x): return 'final result is %s' % x def result(res): print res def aBlockingMethod(): print 'going to sleep...' time.sleep(10) print 'woke up' def main(): lc = LoopingCall(main_loop) lc.start(2) d = defer.Deferred() d.addCallback(aBlockingRedisCall) d.addCallback(result) reactor.callInThread(d.callback, 1) reactor.run() if __name__=='__main__': main() So my question is, does anyone know why my alteration causes the deferred thread to be blocking and/or can anyone suggest a better solution?

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