Error Handling: VI response to any error

Hey guys,
I need to make sure a piece of code executes whenever there is any error in the VI. I'm pretty new to Labview, and cannot wrap my head around "extracting" the errors, so I can pass them into an error handler... All I want, is for my code to find out that there is an error, take some action, and then stop execution.
Any help is greatly appreciated, thanks!
Solved!
Go to Solution.

You simply wire the error wire to the selector of a case structure. Click on file/new/from template/frameworks/SubVI with Error Handling
=====================
LabVIEW 2012

Similar Messages

Error handling function: ORA-20001: get_dbms_sql_cursor error:ORA-00942: table or view does not exist is not trapped. Why?

Why APEX 4.1 Error handling function does not trap the error of missing table?
Say, I create simple application with single IR report page and I also assign standard simple error handling function.
Function works perfectly, except but this case:
If I just drop a table used by report page and then refresh the page I am getting usual APEX error message:
ORA-20001: get_dbms_sql_cursor error ORA-00942: table or view does not exist
and error handling function is not invoked at all.
Is this a feature or a bug?

Hi,
Check the corrections given in the note 990764:
Reason and Prerequisites
Up to now, using a characteristic with its own master data read class as the InfoProvider was not supported. This is now released but it is not available for all modelings. Using the attributes in the query is not supported for characteristics that have their own master data read class. Using the attributes in the query causes a termination. The following errors may occur in this case:
ORA-00942: table or view does not exist
Fehler in CL_SQL_RESULT_SET Include NEXT_PACKAGE
RAISE_READ_ERROR in CL_RSDRV_VPROV_BASE
Solution
SAP NetWeaver 2004s BI
Import Support Package 11 for SAP NetWeaver 2004s BI (BI Patch 11 or SAPKW70011) into your BI system. The Support Package is available once Note 0914305 "SAPBINews BI 7.0 Support Package 11", which describes this Support Package in more detail, has been released for customers.
In urgent cases you can implement the correction instructions.
The correction instructions contain the tightened inspection for characteristics.
Regards,
Anil Kumar Sharma .P

Basic error handling: how to catch all errors in a portion of code (and act accordingly)

I have a portion of code in a VI that I know is likely to fail at some point (opening a file, then reading two arrays from it: the file can be absent, or contain the wrong data).
I would like to be able to catch any errors that may occur during this procedure, and if such an error occurs launch a pre-defined action (return a default value, for instance).
Is there a simple way to do this, in a way similar to the disabling of a portion of code with a Diagram Disable structure ?

use the "bundle by name" function to set the individual elements of the error cluster to the values you want.
CLA, LabVIEW Versions 2010-2013

Error in 'eMail Response - Process Message' --- Error running sub-process 'eMail Response - Create Activity' at step 'Create Activity Process'.(

Hi,
When I was simulating the 'eMail Response - Process Message', I had been getting the below error when entering to 'Create activity Process' step.(provided all the inputs per testmode.xml file)
Error running sub-process 'eMail Response - Create Activity' at step 'Create Activity Process'.(SBL-BPR-00183)
I increased the log level to 5 and got the below message in log file
ObjMgrBusServiceLog InvokeMethod 4 0000000251b51f04:0 2013-06-10 01:30:12 Begin: Business Service 'XML Hierarchy Converter' invoke method: 'DocToHier' at 12cc4240
ObjMgrBusServiceLog Error 1 0000000251b51f04:0 2013-06-10 01:30:12 (xmlcnvsv.cpp (548)) SBL-EAI-00246: XML Hierarchy Converter error - empty input message, expecting an XML document in <Value> of input arguments
I was wondering I could not find 'XML Hierarchy Converter' business service in 'eMail Response - Process Message' and 'eMail Response - Create Activity' sub process.
Can any body help me out in this regard.
Thanks in advance..
Jagadeesh

Hi Naresh,
yes, I am using the delete polling strategy. Here is the .jca file:
<adapter-config name="Pozadavky" adapter="Database Adapter" wsdlLocation="Pozadavky.wsdl" xmlns="http://platform.integration.oracle/blocks/adapter/fw/metadata">
<connection-factory location="eis/DB/PozadavkyConn" UIConnectionName="PozadavkyConn" adapterRef=""/>
<endpoint-activation portType="Pozadavky_ptt" operation="receive">
<activation-spec className="oracle.tip.adapter.db.DBActivationSpec">
<property name="DescriptorName" value="Pozadavky.Pozadavky"/>
<property name="QueryName" value="PozadavkySelect"/>
<property name="MappingsMetaDataURL" value="Pozadavky-or-mappings.xml"/>
<property name="PollingStrategy" value="DeletePollingStrategy"/>
<property name="PollingInterval" value="120"/>
<property name="MaxRaiseSize" value="1"/>
<property name="MaxTransactionSize" value="10"/>
<property name="NumberOfThreads" value="1"/>
<property name="ReturnSingleResultSet" value="false"/>
</activation-spec>
</endpoint-activation>
</adapter-config>

Exception and Error Handling from SRDemo giving duplicate errors.

Hi ,
I used code from SRDemo for Exception Handling and its giving me issue that all the error are get duplicate for every exception .
I have debug it because of reportErrors(final PageLifecycleContext ctx) invoked twice with same Exception in it .
Its get duplicated in UI .
Thanks in advance.

A small update. I tried again by upgrading the PCO version to 15.0 But still the same.
I did the following 2 test cases:
Unplug the UTP cable to the PLC and write data via PCO query
Disable the agent instance and write data via PCO query
In both cases the PCO Query returned the following output:
Success: 1
LastErrorMessage: <empty>
The only information that I get is in the results but it is not a good practice to interpret this because I don't know all the possible messages.
Result for Case 1:
<?xml version="1.0" encoding="UTF-8"?><Rowsets CachedTime="" DateCreated="2015-03-26T14:13:18" EndDate="2015-03-26T14:13:12" StartDate="2015-03-26T13:13:12" Version="14.0 SP5 Patch 12 (1-okt-2014)">
    <Messages>
        <Message>PoederMagazijn/ATS PLC/M1 Order Dispatch/ProductDescription: Unspecified error</Message>
        <Message>PoederMagazijn/ATS PLC/M1 Order Dispatch/ProductDescription: Operation failed</Message>
    </Messages>
</Rowsets>
Result for Case 2:
<?xml version="1.0" encoding="UTF-8"?><Rowsets CachedTime="" DateCreated="2015-03-26T12:11:37" EndDate="2015-03-26T12:11:35" StartDate="2015-03-26T11:11:35" Version="14.0 SP5 Patch 12 (1-okt-2014)">
    <Messages>
        <Message>PoederMagazijn/ATS PLC/M1 Order Dispatch/OrderQuantityTarget: java.net.ConnectException: Connection refused: connect</Message>
        <Message>PoederMagazijn/ATS PLC/M1 Order Dispatch/OrderQuantityConfirmed: java.net.ConnectException: Connection refused: connect</Message>
    </Messages>
</Rowsets>
Please advice. I cannot provide any transaction integrity at this time. I would assume this to be one of the base principles of PCO.

XML Form Build Error Unexpected http response code 500: Error

Dear All,
I am facing the error when I am starting the XML Forms Builder.The tool checks the environment in which the XML Forms Builder is running (xfbuildertest.html)
I am getting the following result :
- Test: Connection Tests
- ! Test Failed !
- A test in the suite failed
- Test: XML Forms Builder Version
- ! Test Failed !
- Unexpected http response code 500: Internal Server Error
Test: Load Global Settings
- Not Started
- This test depends on the test "XML Forms Builder Version", which did not complete successfully
- Test: Load Project List
- Not Started
- This test depends on the test "XML Forms Builder Version", which did not complete successfully
Please help me.
Regards
Pravesh

Hi Lorcan.
So what exactly happens when you try to start XML Forms builder, do you get an actual error or does it just not start at all?
> Actually the News are not getting displayed . The HTML (Html tages)are not getting rendered properly in XML Form Builder.
This news are perfectly working in other environment (Dev/Qlty) but not in Production .. where i am facing the issue of rendering the news ( not in correct format as expected)
It is appearing as link. where as in my other environment the Text in proper HTML format.
(Link of News appearing in production) whereas in Dev/Qlty proper text with Heading/Font/Colour appears. Or are you only seeing errors when you run the environment check?
> I am getting the errors when running the environment check on in Production but not in Development/Quality.
Did you try it on different clients or with different users? Is this a new installation or have you recently upgraded? Are all your components on the same SP level?
> This is new installation but SP level are exactly same across the system(Dev/Qlty/Prod).
Also the check the settings and found proper..
Root Directory * /usr/sap/<System-ID>/SYS/global/config/cm/etc*
Please let me know am I missing something..
Why its not running on my production system.
Regards
Pravesh

Query regarding handling and monitoring of OSB Errors in a specific manner

Hi,
I'm using
- OSB 10gR3 (10.3.1)
Context
To give some context, the setup I currently have a proprietory frontend client that is making XML/HTTP requests to OSB
which in turn is getting info from downstream systems.
I have no control over the behaviour/logic of the frontend client .. apart from knowing that it has a specific
request/response format.
So now to the issue..
The issue I'm facing is regarding handling of errors. Based on my knowledge of OSB, the error handling of the transaction has been
built along these lines
(Within the stage) If an error scenario's occurred, error is being thrown
(Within the error handler stage) Logging the error (using the 'Log' function .. with severity 'Error')
(Within the error handler stage) The response payload is being built .. so that the error can be reported to the frontend client
(Within the error handler stage) I'm doing a 'Reply with Success'
Now this does give me the expected behavior from the frontend client's perspective (... i.e. it receives the payload and displays whatever error that's occurred)
However from OSB's perspective, because I have done a 'Reply with success', the OSB Service Health Page ... (screenshot below) does not
increment the 'Errors' count for the respective proxy service ....
[OSB Service Health Page|http://download.oracle.com/docs/cd/E13159_01/osb/docs10gr3/operations/monitoring.html#wp1107685] (Looking at Figure 3-8)
The only way I could achieve this was to set the error handler stage to 'Reply with Failure' (which would return HTTP 500) ...
The issue however is that, the proprietory frontend simply sees the incoming HTTP 500 code and doesn't read the return XML payload (containing the error details ..)
which beats the whole idea of being able to maintain some sort of traceability for the failed transactions.
So what I'm basically trying to find is .. that when an error occurs
- Some 'call' to make the during the error handler stage so that it registers as an error in the OSB Service Health Page.. and I can clearly
see the error count, etc for each of the proxy services
- After that being able to still use 'Reply with Success' ... so that the payload is being returned with HTTP 500 code...
so the frontend can read the payload ...
............. in essence, the idea being to register errors so that they can be monitored via the Service Health Dashboard ..but at the same time
being able to return the 'error details' payload successfully
With my limited (but growing) knowledge of OSB .. I've tried quite a few ways to achieve this with no success...
Would very much appreciate any help here ...
Lastly, if there is some way of achieving what I'm trying to get to above through different means, I'm open
to trying out alternate stuff.
Regards,
Himanshu

Hi Atheek,
Many thanks for the reply. Does appear to be a pretty neat way of doing it ..
One more clarification I'd like on this however ....
Given that I have a set up like this below
[External frontend client] <------> (1 Parent Service) <------> (2 Child Service)
(1 Parent Service) .... has error handler .. and all it does is 'Reply with success'
(2 Child Service) .... has error handler for particular stage
so...
2 Child Service - is doing the actual work (has error handler where custom error msg is being populated in $body)
1 Parent Service - is the one that is getting called by the external client (has error handler .. and all it does is 'Reply with success')
What I currently have is ..once the error occurs, I'm populating $body ... with the custom error message within the error handler
Previously I had 'Reply with Success' in the 2 Child Service's error handler and the custom error message would get returned to the external client.
Now, with the error handler only creating the custom error msg.... and 1 Parent service doing the 'Reply with Success' .. it doesn't appear
to return the $body .. with the custom msg that I'd populated .. in 2 Child Service's error handler.
Are the $body contents populated in 2 Child Service's error handler lost ...once the error propagates up to 1 Parent service's error handler ?
If yes... is there way of getting around it ? I could see for instance that the $fault message context has a 'user populated' Details variable
but the documentation covering this is sparse.
Regards,

Error handling in overridden methods in AbstractPageBean

Hi,
I'm writing a small app in JSF. One of the pages populates a bunch of text fields from an XML file whose name is passed into the app as an initialization parameter. The purpose of the page is to allow editing of the fields.
It seemed that the prerender() method was the right place to initialize the fields in the form. I have an application-scoped bean trying to open the XML file. I don't want the app to barf on initialization if the file doesn't exist, because the application contains the logic to create the file. So it just sets the appropriate forward target ("file does not exist" page, or maybe XML parse error) and lets the pages that use those bean properties decide when and if they need to display the initialization error page.
I would like to throw an exception from the prerender() method in my page, and have the error handling specified in web.xml. The problem, of course, is that I can't throw my own exception from prerender().
So, have I got the wrong place to initialize my form, or do I have to throw a javax.faces.FacesException, or have I got this whole error-handling thing wrong?
Any advice would be gratefully received.
Many thanks.
Regards,
Mike
public void prerender(){
        // Get ApplicationBean1 to forward the request if we fail to
        // initialize properly.
        ApplicationBean1 ab1 = getApplicationBean1();
        HttpServletRequest req = (HttpServletRequest) this.getFacesContext().
                getExternalContext().
                getRequest();
        HttpServletResponse res = (HttpServletResponse) this.getFacesContext().
                getExternalContext().
                getResponse();
        if(!ab1.isInitialized()){
            //The initialization code for ApplicationBean1() sets the
            //target when it detects an error and then forwards the
            //request to that target upon invocation of the forwardRequest
            //method
            ab1.forwardRequest(req,res);
        // These are the input components
        tfClonebase.setValue(ab1.getClonebase());
        tfDhcpdconf.setValue(ab1.getDhcpdconf());
        tfNamedrev.setValue(ab1.getNamedrev());
        tfNamedzone.setValue(ab1.getNamedzone());
        tfPxelinux.setValue(ab1.getPxelinux());
        tfXmldir.setValue(ab1.getXmlDir());
    }

Well, I'm certainly no expert, but prerender() is called, as you might expect, just before rendering takes place (but only if the page will actually be rendered). This means it won't be called for a page that handled a postback but then navigated to a different page. Good place to handle initializations that happen before rendering.
So my thinking was that I could initialize stuff before there's anything in the response, making it easier to bail out if something goes bad.
But I really can't work out the right way to bail out: I can't throw my own exception because the prerender() is overridden from AbstractPageBean. So I suppose I could create a MikesBadInitException e and throw it inside a new javax.faces.FacesException(e). But I'd like to specify an error-page in my web.xml for MikesBadInitException, and don't want to handle all javax.faces.FacesExceptions, if you get my drift.

LV7.1 Strange behavior with Automatic Error Handling occuring when it shouldn't [LV 7.1 Pro on WinXP for Tablet PC's]

[LV 7.1 Pro on WinXP for Tablet PC's]
I recently let a rather large LV app of mine run in the development environment while I was out for a couple of days. Upon returning I found that the app had hung for ~22 hours waiting for an answer to an Automatic Error Handling (AEH) dialog proclaiming an Error 7 in New File without any indication of the VI hierarchy that called New File. I set about ensuring that AEH dialogs would not pop up and have not been able to discover how I could have possibly received one in the first place.
Subsequent investigation revealed:
Neither AEH option in Options>Block Diagrams were checked.
Network problems had occurred around the time that the app had hung. All file paths are network paths when running in the development environment, so the cause of the error was most likely valid, even if the AEH dialog appearance wasn't.
My app has only one instance where the New File primitive is used by me. That subVI and all others above it in the hierarchy DO NOT have the AEH property enabled. The error out cluster of New File in my subvi is wired.
My app has three instances where New File is called from a vi.lib vi (Open/Create/Replace File.vi, Open Config Data.vi, and Prompt Web Browser Path.vi), none of which have the AEH property enabled. Nor does any of their calling VI's. All three instances also have their error out cluster wired.
A utility to examine the AEH property of all VI's (with all top level and dynamic VI's loaded) in memory reported that only 1 of 308 vi's ( RGT Does File Exists.vi from the Report Generation Toolkit) had that property true. That vi has no subVI's other than the File/Directory Info primitive and no calling VI's in common with any of the vi's that call New File, except a top level VI.
As long as 'Enable automatic error handling dialogs' remains unselected in options>block diagram, I am unable to get an AEH dialog for either the New File or File/Directory Info primitives in a test VI with AEH property enabled and their error out clusters unwired no matter what invalid path I pass to the functions. As soon as the options>block diagram>Enable AEH dialogs' is selected, both primitives fire AEH dialogs with no error out wired and don't when wired. i.e. works as advertised.
In other words I can find no reason why I should have gotten the problem AEH dialog...
I cannot afford for this app to hang because of a network problem, other portions of the app that were running concurrently correctly handled the error and, had the AEH dialog not appeared, the app would have made corrections or shutdown in an orderly fashion.
Any ideas?

Very good.
Write Characters to File.vi>Open/Create/Replace File.vi>New File
New File throws the error. Open/Create/Replace strips the hierarchy from the source of the error. Write Characters passes it to the General Error Handler. I never looked above O/C/R file in the hierarchy except for enable automatic error handling property. The tip-off should have been to realize that O/C/R file was stripping the hierarchy from the error and look above that.
The real irony is that Write Characters was being used to log error cluster data to an error log file...
Save as... Copy without updating... the OEM 'Write Characters to File' is gone from this app.
Thanx (a bunch)

Error Handling in Mediation for sequential Invocation in Routing rules

Hi all,
I have a situation File Adapter->Mediator->BPEL Process 1->BPEL Process 2.When an error occurs in BPEL Process 1 a soap fault is returned to the mediator service.
Now since the mediator service invokes BPEL process 1 synchronously hence the fault policy is by-passed and the error is returned to the file adapter(the caller).
I have configured rejection handling in the fault-policy file as below -
_+<faultName xmlns:rjm="http://schemas.oracle.com/sca/rejectedmessages" name="rjm:pollFlatFiles">+_
_+<condition>+_
_+<action ref="ora-ws"/>+_
_+</condition>+_
_+</faultName>+_
_+<service faultPolicy="RejectionMessageHandlerPolicy">+_
_+<name>pollFlatFiles</name>+_
_+</service>+_
The following scenario occurs when trying to test the error handling -
1.First when the error occurs in BPEL processes 'oracle.fabric.common.BusinessFaultException' is thrown at the composite level and no message is rejected by the file adapter.
2.Immediately when the errors occurs for a second time the messages gets rejected and my rejection handler is called since the following exception is thrown from the file adapter -
The adapter has exceeded maximum configured retries. The adapter was unable to process "{0}" after having retried for {1} times, now the adapter will reject the message. This exception usually comes due to errors in downstream systems. Please increase the value for "jca.retry.maxRetries" in composite.xml for the inbound service and redeploy.
I have tried increasing the retry count also in composite.xml but the same sequence occurs i.e-
First time business exception.
Next time message rejection.
Any idea how the error can be properly handled in synchronous invocation to avoid this situation so that the messages always get rejected?
I am using SOA Suite 11.1.1.2.0 version.
Thanks and Regards,
Mandrita.

Hi samay,
In the transfer rules, if returncode is not 0, the upload stop,so..
Actually I delete the "wrong" data in the start routine of the transfer rules

How to create a generic error handling proxy?

Hello,
i have few services proxies.
I want to create a generic error handling osb proxy which does only errorhandling.
This proxy would be called by all my services.Now suppose my services proxies would throw any error,the control will pass to error handling block of proxy..from there i will call this generic errorhandling proxyusing a service callout or publish action.In this proxy i want to do all my error handling based on 'n' conditions.and i want to pass the message to the fault variable of services proxy..kindly suggest ways..*main challenge is passing the message to the fault variable of services proxy*

Hi,
For generic error handling framework or common error handling framework...create a bpel process which takes the error details payload and sends the inf/data as email to the particular receipients.
create business process with bpel process and proxy using business service.so wen ever error occurs at stage or route or proxy level ..call error handler action in OSB.Assign error handler details to the bpel input payload.
FOR EX:
<soap-env:Body xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
<com:test>
<com:ProcessInfo>testDetails</com:ProcessInfo>
<com:BusinessProcessName>testprocess</com:BusinessProcessName>
<com:BusinessProcessInstanceId>{fn-bea:uuid()}</com:BusinessProcessInstanceId>
<com:BusinessProcessStep>ReqLayer</com:BusinessProcessStep>
<com:ErrorCode>{string($fault/ctx:errorCode)}</com:ErrorCode>
<com:ErrorType>Technical</com:ErrorType>
<com:StatusCode>Error</com:StatusCode>
<com:ImplementationCode>OSB</com:ImplementationCode>
<com:ErrorDescription>{string($fault/ctx:reason)}</com:ErrorDescription>
<com:ErrorDateTime>{fn:current-dateTime()}</com:ErrorDateTime>
<com:Node>{string($fault/ctx:location/ctx:node)}</com:Node>
<com:Path>{string($fault/ctx:location/ctx:path)}</com:Path>
</com:test>
</soap-env:Body>
this assign the error details values to the bpel process.

Error handling in Portal standard forms

I have a customer who needs to validate input on a Form Based on a Table (standard component). They have tried code, as shown below, as a PLSQL handler on a Save button. This example can obviously be solved with JavaScript validation on the client, but they have similar requirements for validation on DB level.
If procedure call 1) in the if statement is used, nothing happens. If procedure call 2) is used, it is executed in a new page as a standard error Oracle Portal error message.
declare
v_sender VARCHAR2(1000);
v_sender_id NUMBER;
begin
v_sender := p_session.get_value_as_VARCHAR2(
p_block_name => 'DEFAULT',
p_attribute_name => 'A_SENDER');
v_sender_id := p_session.get_value_as_NUMBER(
p_block_name => 'DEFAULT',
p_attribute_name => 'A_SENDER_ID');
insert into hd (number, text) values (hd_seq.nextval,
'step 3 v_sender = ' || v_sender ||
' v_sender_id = ' || v_sender_id);
if v_sender_id >= 100 then
1) Custom error handling, does not display:
show_error('Error message');
2) Error handling is displayed, but as a standard error:
raise_application_error(-20000, 'SenderID must be smaller than 100.');
else
doInsert;
end if;
end;
The customer has two questions:
Why does the custom procedure in 1) "show_error" not execute, and if it does, why does it not display? show_error works and the if statement is entered.
Is it possible to take control of Portals error handling on standard components (forms etc.), to show custom error messages with the style used on the component/page instead of the standard Error: ORA- ....etc. as Portal displays it?
Customer needs reply asap. Please reply directly. Any help will be much appreciated!
Kind regards
Jakob Lund

Jacob,
Try following:
declare
v_sender VARCHAR2(1000);
v_sender_id NUMBER;
begin
v_sender := p_session.get_value_as_VARCHAR2(
p_block_name => 'DEFAULT',
p_attribute_name => 'A_SENDER');
v_sender_id := p_session.get_value_as_NUMBER(
p_block_name => 'DEFAULT',
p_attribute_name => 'A_SENDER_ID');
insert into hd (number, text) values (hd_seq.nextval,
'step 3 v_sender = ' || v_sender ||
' v_sender_id = ' || v_sender_id);
if v_sender_id >= 100 then
p_session.set_value(
p_block_name => "_block",
p_attribute_name => '_STATUS',
p_value => 'Sender ID must be less than 100!');
-- return to your form with status message set
-- and all fields filled with recent values
return;
end if;
end;
-- This point is reached only if validation is OK
doInsert;
Regards,
Henn

Received HTTP response code 500 : Error during conversion of XI message

hi
Facing the error , "Received HTTP response code 500 : Error during conversion of XI message"
This is the fist time i am configuring the sender soap ( Axis Framework in the SOAP Adapter) (Quality of service Best effort) communication channel and i am getting the above error did any body face this error.
01.09.2011 12:02:32     Information     The message status was set to DLNG.
01.09.2011 12:02:32     Error     SOAPFault received from Integration Server. ErrorCode/Category: XIServer/ATTRIBUTE_INITIAL; Params: Manifest cid:6D90482BF678436D75928FC8B9930519; AdditionalText: null; ApplicationFaultMessage: null; ErrorStack: Attribute Manifest cid:6D90482BF678436D75928FC8B9930519 is initial
01.09.2011 12:02:32     Error     Transmitting the message using connection SOAP_http://sap.com/xi/XI/System failed, due to: com.sap.engine.interfaces.messaging.api.exception.MessagingException: Received HTTP response code 500 : Error during conversion of XI message.
regards
sandeep
Edited by: pendyalas on Sep 1, 2011 12:20 PM

I found a link with respect to similar error , sap note 1522630 has been used to resolve this error.
i will try and see if it works.
AXIS Sender Adapter Failure after upgrade to PI 7.11 SP06
regards
sandeep

'Structured' error handling and reentrancy

The parentheses in the subject are due to the fact that I'm not using the Structured Error Handler reference library, but have rolled my own to do something similar but in the manner I want it to. I don't actually use the SEH (haven't even got it installed at the moment on this PC) so am not sure exactly how it works under the hood.
I have a reasonably large application with a number of distinct parallel modules (GUI, state module, communication, motion control). The final parallel module is an error handling module. This consists of two queues - one for incoming errors, and one for outgoing actions. Errors are dequeued and their codes checked for their category (critical, warning, ignore or unclassified, for instance) and the appropriate category is returned to a local error handler via the action queue. When an error is passed to a local error handler VI, it enqueues the error to the main handler and waits for a response to that particular error.
This all works nicely, in much the same way the SEH would do. However, with either the SEH or my local error handler method, I find myself wondering how often to place these down and the consequences of doing so. If they're non-reentrant, I imagine I may end up with lots of parallel processes sitting patiently to access the VI as it's blocked by another, causing jitter. If I go pre-allocated clone, I could potentially have many many callers using this function, which strikes me as a bit of a waste of resources. My gut feel is to go with shared-allocation clones, as the vast majority of the time it'll be no error passed through an empty case, and not to place them in absolutely every subVI - just perhaps after a state executes in the state handler, in all the parallel loops of the submodules etc.
Just wondering what anyone else does with their error handling solution, and whether my thoughts make sense.
CLD

Having chatted to my friendly neighbourhood Spiderman Architect, he suggested I should probably just stop being a wimp and just use pre-allocated clones to avoid the jitter and to stop worrying about the resource hit, as you suggest
I'll use the same code on both PC host and RT host, hence the jitter concerns on the RT.
Thanks for the thoughts!
CLD

How to ignore a DML operation using error handler.

In our streams replication application (using Oracle 10G), we have error handler to handle the errors at destination apply process. It uses straight apply process no DML handlers except error handlers. The error handler should just log the error and LCR info into the error log table and discard the DML LCR. Error logging is not a problem. But the problem is how to ignore the error DML LCR and move to next LCR in the same transaction without rollback of the transaction or any error.
Another question, do I need to use LCR.EXECUTE() procedure to continue the transaction in case of errors?
Appreciated your help.

Thanks for reference, confirmation of use of execute function.
I read those pages and other related pages in "Oracle® Streams Concepts and Administration" too.
I am able to write an error handler to handle errors with regular apply process. It is logging "no data found" errors but failing in case of foreign key violations. Error handler takes any kind of error and logs a record into errorlog table and ignores the error. I think it is not calling error handler. I checked for handlers in dba_apply_dml_handlers table. There is a handler for Inert, update and delete. I am investigating it further now. If you have any leads, please post.
Thanks for your time and help.
Dharma

Error Handling: VI response to any error

Similar Messages

Maybe you are looking for