I'm wondering is there a way to recognize the OfflineComamd is being executed or internal flag or something to represent this command has been passed or mark it has been executed successfully. I have issue in recognizing the command is passed or not with unstable internet. I keep retrieve the records from database and comparing each and every time to see this has been passed or not. But due to the flow of my application, I'm finding it very difficult to avoid duplicates.IS there any automatic process to make sure commands executed automatically or something else?
2nd question, I can use UITimer to check isOffline() to make sure internet is connected or not on the forms. Is there something equivalent on server page or where queries is written to see internet is disconnected or not. When the control moved to queries and internet is disconnected I see the dialog open from form page being frozen for unlimited time and will not end. I have to close and re-open the app to continue the synchronization process.At the same time I cannot set a timeout for dialog because I'm not sure how long it will take the complete the Synchronization process. Please advise.
Extending on the same topic but I have created a new issue just to give more clarity on my questions.
executeOfflineCommand skips a command while executing from storage on Android
There is no way to know if a connection will stay stable as it requires knowledge of the future. You can work like transaction services do where the server side processes an offline command as a transaction using the approach of 2-phase commit.
In this approach you have an algorithm similar to this:
Client sends command to server
Server returns a special unique ID for the command
Client asks server to perform the unique id
Server acknowledges that the command was performed
If the first 2 stages didn't complete you just do that again. The worst thing that could happen is some orphan commands on the server.
If the 3rd option didn't complete you just do it again. The server knows whether it processed the command and will just acknowledge it if it was already processed.
Related
I have a select based server system, where I can manage multiple clients. The server automatically reads and responds to the client, which is great. But there's a minor issue. For instance user#1 changes directory (coded with chdir), all of the other users are affected by this change. I really do wish that prevented for happening.
There's two ways to solve this:
Fork off a separate process to handle each connection. This process can have its own state, including current working directory. The disadvantages are that you'll need to refactor your code quite a lot, and if you have a lot of concurrent connections then it can be a performance problem. This is harder on Windows that *nix, but not impossible.
Keep the current directory as a per-connection setting within your program, and (re)set the directory before executing every user command.
I have several HTTP callouts that are in a schedulable and set to run ever hour or so. After I deployed the app on the app exchange and had a salesforce user download it to test, it seems the jobs are not executing.
I can see the jobs are being scheduled to run accordingly however the database never seems to change. Is there any reason this could be happening or is there a good chance the flaw lies in my code?
I was thinking that it could be permissions however I am not sure (its the first app I am deploying).
Check if the organisation of your end user has added your endpoint to "remote site settings" in the setup. By endpoint I mean an address that's being called (or just the domain).
If the class is scheduled properly (which I believe would be a manual action, not just something that magically happens after installation... unless you've used a post-install script?) you could also examine Setup -> Apex Jobs and check if there are any errors. If I'm right, there will be an error about callout not allowed due to remote site settings. If not - there's still a chance you'll see something that will make you think. For example batch job has executed successfully but there were 0 iterations -> problem?
Last but not least - you can always try the debug logs :) Enable them in Setup (or open the developer console), fire the scheduled class's execute() manually and observe the results? How to fire it manually? Sth like this pasted to "execute anonymous":
MySchedulableClass sched = new MySchedubulableClass();
sched.execute(null);
Or - since you know what's inside the scheduled class - simply experiment.
Please note that if the updates you might be performing somehow violate for example validation rules your client has - yes, the database will be unchanged. But in such case you should still be able to see failures in Setup -> Apex Jobs.
I've implemented a messaging system over SQL Server Service Broker. It is working great, with the sole exception that every once in a while (maybe once per week per server) my initiator service just vanishes without a trace. The corresponding queue is still there, but the service is missing.
Obviously this causes problems in my system. It's a simple matter to recreate the service by hand, but I'm confused as to what might cause this behavior. I understand that automatic poison message handling causes queues to be disabled, but I don't see anything that indicates services can be disabled or deleted automatically.
When this happens, I usually have a large backlog of messages in multiple application queues, but nothing extreme. Total message backlog is around 200,000.
Does anyone know what might be happening here?
You must have a bug of some sort that issues a DROP SERVICE statement. That is the only way a service gets deleted.
Check the default trace, the DROP statement gets traced and saved into it so you can track down the application/user/statement that issues the DROP. Check sys.traces to find the location of the default trace then open the .TRC file in Profiler.
We are using ASP.NET MVC with LINQ to SQL. We added some features and tested them all to perfection on our QA box. We are using Windows Server 2003 and SQL Server 2005. So when we pushed out changes to the Live web server we also used Red Gate SQL Compare to push new database changes to the LIVE database. We tested again between the few of us, no problems. Time for bed.
The morning comes and users are starting to hit the app, and BOOM. We have no idea why this would happen as we have not been doing any new types of code things that we were not doing before. However we did notice that during the SQL Compare sync the names of all the foreign keys were different between the two databases, not the IDs in the tables, FK_AssetAsset_A0EB67 to FK_AssetAsset_B67EF8 (for example, don't remember the exact number of trailing mixed characters during the SQL Compare), we are not sure why but that is another variable in this problem.
Strangely once this was all pushed out we could then replicate the errors on QA, but not before everything was pushed to LIVE.
QA and LIVE databases are on the same SQL Server, but the apps are on different instances of Windows Server 2003.
Errors generated:
Index was outside the bounds of the array.
Invalid attempt to call FieldCount when reader is closed.
Server failed to resume the transaction.
There is already an open DataReader associated with this Command which must be closed first.
A transport-level error has occurred when sending the request to the server.
A transport-level error has occurred when receiving results from the server.
Invalid attempt to call Read when reader is closed.
Invalid attempt to call MetaData when reader is closed.
Count must be positive and count must refer to a location within the string/array/collection. Parameter name: count
ExecuteReader requires an open and available Connection. The connection's current state is connecting.
Any one have any idea what the heck could have happened?
EDIT: Since we were able to replicate the errors all of a sudden on QA, it might not be a user load issue... Needless to say we all feel really screwed here.
Concurrency always brings bugs out of the woodwork. I'd recommend you check for objects that could be shared among requests (such as static members and singletons) and refactor your code so that as little as possible is shared.
As far as specifics go, for the error "There is already an open DataReader associated with this Command which must be closed first," you may want to try adding MultipleActiveResultSets=True to your connection strings.
It sounds like you're crossing the streams a bit and trying to share DataContexts across requests. My suggestion would be to wire in a dependancy injection framework that creates a new instance of the dependancy for each request.
I use Castle's IoC and wire it into the controller factory so that when it sees a dependancy on a repository it creates a new instance of that repository for each request. If you go this route let me know and I can shoot you a few more resources.
I want to be able to copy the file I have which comes in as XML into a new folder location on the server. Essentially I want to hold a back up of the input files in a new folder.
What I have done so far is try to follow what has been said on this forum post - link text
At first I tried the last method which didn't do anything (file renaming while reading). So I tried one of the other options and altered the orchestration and put a Send shape just after the Receive shape. So the same message that comes in is sent out to the logical port. I export the MSI, and I have created a Send Port in the Admin console which has been set to point to my copy location. It copies the file but it continues to create one every second. The Event Viewer also reports warnings saying "The file exists". I have set the Copy Mode of the port to 'overwrite' and 'Create New', both are not working.
I have looked on Google but nothing helps - BTW I support BizTalk but I have no idea how pipelines, ports work. So any help would be appreciated.
thanks for the quick responses.
As David has suggested I want to be able to track the message off the wire before BizTalk does any processing with it.
I have tried to the CodePlex link that Ben supplied and its points to 'Atomic-Scope's BizTalk Message Archiving Pipeline Component' which looks like my client will have to pay for. I have downloaded the trial and will see if I have any luck.
David - I agree that the orchestration should represent the business flow and making a copy of a file isn't part of the business process. I just assumed when I started tinkering around I could do it myself in the orchestration as suggested on the link I posted.
I'd also rather not rely on the BizTalk tracking within the message box database as I suppose the tracked messages will need to be pruned on a regular basis. Is that correct or am I talking nonsense?
However is there a way I can do what Atomic-Scope have done which may be cheaper?
**Hi again, I have figured it out from David's original post as indicated I also created a Send port which just has a "Filter" expression like - BTS.ReceivePortName == ReceivePortName
Thanks all**
As the post you linked to suggests there are several ways of achieving this sort of result.
The first question is: What do you need to track?
It sounds like there are two possible answers to that question in your case, which I'll address seperately.
You need to track the message as received off the wire before BizTalk touches it
This scenario often arises where you need to be able to prove that your BizTalk solution is not the source of any message corruption or degradation being seen in messages.
There are two common approaches to this:
Use a pipeline component such as the one as Ben Runchey suggests
There is another example of a pipeline component for archiving here on codebetter.com. It looks good - just be careful if you use other components, and where you place this component, that you are still following BizTalk streaming model proper practices. BizTalk pipelines are all forwardonly streaming, meaning that your stream is readonly once, and all the work on them the happens in an eventing manner.
This is a good approach, but with the following caveats:
You need to be careful about the streaming employed within the pipeline component
You are not actually tracking the on the wire message - what your pipeline actually sees is the message after it has gone through the BizTalk adapter (e.g. HTTP adapter, File etc...)
Rely upon BizTalk's out of the box tracking
BizTalk automatically persists all messages to the message box database and if you turn on BizTalk tracking you can make BizTalk keep these messages around.
The main downside here is that enabling this tracking will result in some performance degradation on your server - depending on the exact scenario, this may not be a huge hit, but it can be signifigant.
You can track the message after it has gone through the initial receive pipeline
With this approach there are two main options, to use a pure messaging send port subscribing to the receive port, to use an orchestration send port.
I personally do not like the idea of using an orchestration send port. Orchestrations are generally best used to model the business flow needed. Unless this archiving is part of the business flow as understood by standard users, it could simply confuse what does what in your solution.
The approach I tend to use is to create a messaging send port in the BizTalk admin console that subscribes to your receive port. The send port will then just use a standard BizTalk file adapter, with a pass through pipeline.
I think you should look at the Biztalk Message Archiving pipeline component. You can find it on Codeplex (http://www.codeplex.com/btsmsgarchcomp).
You will have to create a new pipeline and deploy it to your biztalk group. Then update your receive pipeline to archive the file to a location that the host this receive location is running under has access to.