From the tutorial session, While I was performing tutorial no 2 suddenly I face error whole I was trying to modify data formula.
The Error is [08S01] Communication link failure
I am new in scribe so, unable to understand exactly what's going on.
So many times ago I face same problem and,
the problem resolved, I just simply restart scribe, and all done...
But As I am thinking this error may be due to the error in connection to the ODBC data connection.
So, in further try to resolve it with ODBC connection.....
Related
I am trying to implement the following example (http://zone.ni.com/reference/en-XX/help/370622M-01/lvmve/using_opcua_svr/) but there seems to be in error in my code which i can't figure out. The error is "Error occurred while reading the node". Below is my Block diagram. If a write before read the error become error
in writing the node.
Probably the write.vi is not wired up properly. The coercion dots should not appear. Try using context help (ctrl+H) and check the wires once again.
Moreover you can use "highlight execution" option to check where the error message come from.
I am trying to scrape data from google and linkedin. Somehow it gave me this error:
*** httperror_seek_wrapper: HTTP Error 503: Service Unavailable
Can someone help advice how I solve this?
Google is simply detecting your query as automated. You would need a captcha solver to get unlimited results. The following link might be helpful.
https://support.google.com/websearch/answer/86640?hl=en
Bypassing Captcha using an OCR Engine:
http://www.debasish.in/2012/01/bypass-captcha-using-python-and.html
Simple Approach:
An even simpler approach is to simply use sleep() a few times and to generate random queries. This way google will not spot that you are using an automated system. But the system is far slower ...
Error Handling:
To simply get remove the error message use try and except
I encountered the same situation and tried using the sleep() function before every request to spread the requests a little. It looked like it was working fine but failed soon enough even with a delay of 2 seconds. What solved it finally was using:
with contextlib.closing(urllib.urlopen(urlToOpen)) as x:
#do stuff with x.
This I did because I thought opening too many requests keeps it open and had to closed. Nevertheless, it worked quite consistently with as less as 0.5s delay time.
I am suddenly getting the error: "Unable to locate persister for the entity named 'MyLib.Project'."
I did not make any code changes to this project since the last time I published it. The reason I went into the code to look at it is because a user reported that the web page that utilizes this library was giving an error. I have also checked the eager loading of the provider as per (NHibernate - Random occurrences of "Unable to locate persister") but I am already eagerly loading.
Furthermore, I even changed my data provider configuration to:
.Mappings(Function(x) x.FluentMappings.AddFromAssemblyOf(Of Project)())
I stepped through the code and actually saw it find the Project mapping and step through it. There are no exceptions thrown while building the provider, but yet the web app still fails when I try to fetch a Project from the DB.
Update
I have tested this same exact code with a desktop application and it works perfectly fine. It seems to me the problem must be with NHibernate and the Web Application. Does anyone have any ideas about this specifically?
The answer to this, of course, is that I made a mistake.
I had two session factories in use in the same program and I passed a session from the wrong factory to one of my functions. So the error is correct, because the session it was passed was unaware of the Project type. I found this out eventually by looking at the Connection property of the session I was querying through.
Hopefully this helps someone else who may have made the same mistake.
I'm trying to understand WCF message routing, so I'm trying to recreate a sample passthrough router that I found in order to understand the pieces. The problem is that when I run mine in the debugger, I get the exception:
Multiple headers with name 'VsDebuggerCausalityData' and namespace 'http://schemas.microsoft.com/vstudio/diagnostics/servicemodelsink' found.
I've read that this is because I'm debugging all the pieces at the same time, and that the debugger is adding this data on each hop? However, I can debug all the pieces in the original sample I'm working from with no errors, so I'm not sure I believe the explanation I've seen, or I don't understand something yet. Anyone have an explanation how I can debug mine without getting this exception?
Can you check if your machine config has element. You might need to comment this out. (Before any changes to machine config do back it up)
Generally, in software design, which of the options below is preferred when there is a problem or error with a resource such as a database or file?
Show an error message
Do not show an error message and act as though the resource was empty (eg. do not populate a GUI component)]
For example, should the user see an empty DataGrid following which they complain, or should there be an error message? Which is better?
I don't see this as an either/or. Also, we need to consider all "users" of the system.
First consider the UI. Let's consider a contrived general case: you are populating a UI by calling a service which in turn uses a couple of of databases (for example a "current data" and an "historic data") database.
There are at least these possibilities:
It all works, data is retrieved
It all works but as it happens there's no data for this particular query
Can't reach the service
Service is invoked, but one database is down
Service is invoked, but both databases are down
Then also consider your application's semantics. Can your applciation procede in a "degraded" mode if all the data cannot be retrieved? For example, we can't query the history but that doesn't stop us creating a new item.,
Now also consider the roles here. There's the person using the UI, there's also support and maintenance people who need to know about and fix problems.
My general rules:
First Failure Data capture: Whichever component first detects an error should log it in some detail. So, service up, database down the service should log the problem. Service down, the UI should log the problem. This log should be a technical record targeting the support roles.
UIs should be tolerant: if at all possible run in a degraded mode. So if the service is down but (for example) local working is possible put up an empty screen and continue. BUT ...
Always indicate a problem: The "no data for this query" and "databases unavailable" cases may both result in an empty screen. The user needs to know the status of the display, is it showing complete information, partial information (eg. because one DB is down) or is no information available (eg. service or both dbs down). So have a "Status" field somewhere on the screen. Giving messages such as
Historica Data not currently available
or
There are problems retrieveing
information, if these persist please
contact support ...
There are some pitfalls to each of the options
Showing error message
This is specially helpful when your application is in testing stage or public testing. Also when clients meets an error, he or she can copy down the details and forward to you.
However sometimes this error message gets very ugly (call stacks and so on - remember ASP.NET?) and it becomes so large that it becomes difficult for clients to copy down the details.
Do not show error message and act as though nothing happened =)
This is useful when you don't want error messages to cog up your software UI design. But be reminded that it becomes difficult and further error prone when clients can't differentiate between an actual error, or really nothing on the GUI. The error stays there and nothing gets fixed.
My stand
Get the best of both worlds. In fact most modern applications how have a very good error handling process. I'll take the example of Mozilla Firefox 3.
A deadly error occurred and Firefox crashes
Error is captured and stored into a file as a form of error report
Error Reporting Application pops up apologizing to the user
Ask the user if the user want to send the error report to the software dev team
Then ask the user if want to restart the application
Or if the error is a warning or of lesser severity:
Show a simple error code and tell the user that there's the error with that action. Something like: "Error 123 at RequestSalary() Line 2"
The practice I usualy use is:
If the error didn't happen due to user error, then you should try to handle the error quietly.
If the error occurred because of some external problem (such as no internet connection) then you should alert the user.
IMO you should show a message (albeit a user friendly one and not something like "java.io.IOException: Connection timed out".) You could have a message box telling the user that an error occured while getting the data and provide helpful tips like: Trying after some time, check network cable, etc.
Also allow user to report that error to you (error reporting build into the app) that will send you the actual error and stack trace.