In my ODL code, I have recently noticed that when uninstalling flows, I get unexpected behavior. The scenario goes something like this:
A bunch of flows are installed across multiple tables
I delete a flow by using the same NodeId, TableId and FlowId that I used when creating it. For reference, I use SalFlowService's addFlow and removeFlow methods.
I execute ovs-ofctl dump-flows and notice that ALL flows on the given node and given table are deleted. For reference, the flowId I use is something like "routing-rename-src-0.0.0.0-to-123.123.123.0".
It appears to me that ODL somehow completely fails at recognizing the FlowId, and defaults to deleting all flows on the given table. No error messages are sent from OpenFlow, and no errors are logged in ODL.
The thing is, I am definitely using the same FlowId object.
Now, I am a bit confused about what could go wrong, but I have an idea, it's just that there's conflicting evidence online, and since I haven't worked on OpenFlowPlugin, I can't quite tell myself.
Flows are or tend to be posted using integers for flowIds, in the REST request paths.
In ODL code such as l2switch, flowIDs can be strings. This makes certain debugging easier to parse through.
Now, this is pretty strange. Are we using integers, or strings, or can ODL make a conversion between integer and strings by a mapping mechanism of sorts? Either way, I get unexpected behavior. Interestingly, the code I linked to does not do deletion... so maybe it's more of a hack in this case?
EDIT : I have now tried to rename my IDs as mere numbers, or as "PluginName" + "-" + number, and uninstallation still seems to fail. The problem is now that I just can't uninstall a flow rule without uninstalling the entire table with it...
EDIT 2 : This issue allowed me to understand that the flow id is not necessarily used to remove the flow. I came up with the following procedure to delete flows, in a way that doesn't cause all flows on the table to get deleted:
final RemoveFlowInputBuilder builder = new RemoveFlowInputBuilder(flow);
builder.setNode(new NodeRef(nodeId));
builder.setFlowRef(new FlowRef(flowPath));
builder.setFlowTable(new FlowTableRef(tableId));
flowIdentity.context.salFlowService.removeFlow(builder.build());
The very difference with my previous code was that I was not using a Flow object to initialize the input builder. In this form, my methods for adding and removing are identical. As long as I preserve the Flow object after adding the flow, I can delete the flow, and the tables will not be wiped.
But there is an exception. On table 0, I have installed two different table-change rules with identical actions, but different priorities. The matches are slightly different (one defines an in-port, the other doesn't). When I delete the most generic (and lowest priority) rule, the other one gets deleted also.
I don't understand why this happens. Even if I try setting the priority in the input builder, this still happens. Hrm.
As I wrote in my second edit, this post suggests that flow deletion does not work explicitly based on Id, but rather, on the fields that are defined in the input builder of the method. I haven't tested this, but I suspect if the flow reference is omitted from the builder, the defined fields will be used to delete all matching rules, which could imply deleting all flows by accident if the wrong fields are set.
Given the following code to add flows:
final AddFlowInputBuilder builder = new AddFlowInputBuilder(flow);
builder.setNode(new NodeRef(nodeId));
builder.setFlowRef(new FlowRef(flowPath));
builder.setFlowTable(new FlowTableRef(tableId));
builder.setPriority(flow.getPriority());
flowIdentity.context.salFlowService.addFlow(builder.build());
The following code to remove flows works as expected (using the SAME Flow object):
final RemoveFlowInputBuilder builder = new RemoveFlowInputBuilder(flow);
builder.setNode(new NodeRef(flowLocation.nodeIdentifier));
builder.setFlowRef(new FlowRef(flowLocation.flowPath));
builder.setFlowTable(new FlowTableRef(flowLocation.tableIdentifier));
builder.setPriority(flow.getPriority());
builder.setStrict(Boolean.TRUE);
flowIdentity.context.salFlowService.removeFlow(builder.build());
Without "strict" set to true, this can cause unexpected deletion of similar rules on the same table. I am unsure of the way flows are matched on deletion, with or without strict, but this much I can confirm.
Related
I am trying to add a formal parameter in the FORM and PERFORM in an existing code, as I will be need it the extra parameter in a new function that I have to call. The idea is that when executing the new code it keeps showing the error: Different parameter count in FORM and PERFORM (routine: CM_SHOW_CRC, number of formal parameters: 2, number of actual parameters: 3).
The code that I have for the form part is as follows:
FORM cm_show_crc
USING
civ_matnr TYPE matnr
civ_charg TYPE charg_d
civ_werks TYPE werks_d. "The parameter that I added
And the perform code is:
PERFORM cm_show_crc
USING
pis_sdow_alv-matnr
pis_sdow_alv-charg
pis_sdow_alv-werks. "The parameter that I added
The table pis_sdow_alv is type of a structure that also includes the variable WERK(Component type WERKS_D)
Before adding the new parameter WERK the code was working fine.
May anyone know what the problem in this part of the code may be?
There was also another similar question in: Different number of parameters in FORM and PERFORM, however I am not using the syntax CHANGING in my code, as it was also not used prior.
Please do tell me if you need additional information.
Thank you all in advance!
This problem can occur when FORM and PERFORM are in different includes and you only activate one but not the other.
When you activate an include, then it is checked against the active version of all other repository objects it depends on. Not the saved version. This can lead to an annoying catch-22 situation. You can not activate A because it does not match the previous version of B, and you can not activate B because it does not match the previous version of A.
The solution to this conundrum is to activate both objects together. When you activate something in SE80 and you have multiple inactive objects, you get a window where you can select multiple objects to activate together:
In Eclipse, you get a similar list by clicking on the "activate multiple" button:
Enterprise Architect 13.5.
I made MDG technology extending Object metatype. I have a shape script for my stereotype working well. I need to print several predefined run-state parameters for element. Is it possible to access to run-state params within Shape ?
As Geert already commented there is no direct way to get the runstate variables from an object. You might send a feature request to Sparx. But I'm pretty sure you can't hold your breath long enough to see it in time (if at all).
So if you really need the runstate in the script the only way is to use an add-in. It's actually not too difficult to create one and Geert has a nice intro how to create it in 10 minutes. In your shape script you can print a string restult returned from an operation like
print("#addin:myAddIn,pFunc1#")
where myAddIn is the name of the registered operation and pFunc1 is a parameter you pass to it. In order to control the script flow you can use
hasproperty('addin:myAddIn,pFunc2','1')
which evaluates the returned string to match or not match the string 1.
I once got that to work with no too much hassle. But until now I never had the real need to use it somewhere in production. Know that the addin is called from the interpreted script for each shaped element on the diagram and might (dramatically) affect rendering times.
Following conversion
SELECT to_tsvector('english', 'Google.com');
returns this:
'google.com':1
Why does TSearch2 engine didn't return something like this?
'google':2, 'com':1
Or how can i make the engine to return the exploded string as i wrote above?
I just need "Google.com" to be foundable by "google".
Unfortunately, there is no quick and easy solution.
Denis is correct in that the parser is recognizing it as a hostname, which is why it doesn't break it up.
There are 3 other things you can do, off the top of my head.
You can disable the host parsing in the database. See postgres documentation for details. E.g. something like ALTER TEXT SEARCH CONFIGURATION your_parser_config
DROP MAPPING FOR url, url_path
You can write your own custom dictionary.
You can pre-parse your data before it's inserted into the database in some manner (maybe splitting all domains before going into the database).
I had a similar issue to you last year and opted for solution (2), above.
My solution was to write a custom dictionary that splits words up on non-word characters. A custom dictionary is a lot easier & quicker to write than a new parser. You still have to write C tho :)
The dictionary I wrote would return something like 'www.facebook.com':4, 'com':3, 'facebook':2, 'www':1' for the 'www.facebook.com' domain (we had a unique-ish scenario, hence the 4 results instead of 3).
The trouble with a custom dictionary is that you will no longer get stemming (ie: www.books.com will come out as www, books and com). I believe there is some work (which may have been completed) to allow chaining of dictionaries which would solve this problem.
First off in case you're not aware, tsearch2 is deprecated in favor of the built-in functionality:
http://www.postgresql.org/docs/9/static/textsearch.html
As for your actual question, google.com gets recognized as a host by the parser:
http://www.postgresql.org/docs/9.0/static/textsearch-parsers.html
If you don't want this to occur, you'll need to pre-process your text accordingly (or use a custom parser).
This might be an odd question, but I'm looking for a word to use in a function name. I'm normally good at coming up with succinct, meaningful function names, but this one has me stumped so I thought I'd appeal for help.
The function will take some desired state as an argument and compare it to the current state. If no change is needed, the function will exit normally without doing anything. Otherwise, the function will take some action to achieve the desired state.
For example, if wanted to make sure the front door was closed, i might say:
my_house.<something>_front_door('closed')
What word or term should use in place of the something? I'd like it to be short, readable, and minimize the astonishment factor.
A couple clarifying points...
I would want someone calling the function to intuitively know they didn't need to wrap the function an 'if' that checks the current state. For example, this would be bad:
if my_house.front_door_is_open():
my_house.<something>_front_door('closed')
Also, they should know that the function won't throw an exception if the desired state matches the current state. So this should never happen:
try:
my_house.<something>_front_door('closed')
except DoorWasAlreadyClosedException:
pass
Here are some options I've considered:
my_house.set_front_door('closed')
my_house.setne_front_door('closed') # ne=not equal, from the setne x86 instruction
my_house.ensure_front_door('closed')
my_house.configure_front_door('closed')
my_house.update_front_door('closed')
my_house.make_front_door('closed')
my_house.remediate_front_door('closed')
And I'm open to other forms, but most I've thought of don't improve readability. Such as...
my_house.ensure_front_door_is('closed')
my_house.conditionally_update_front_door('closed')
my_house.change_front_door_if_needed('closed')
Thanks for any input!
I would use "ensure" as its succinct, descriptive and to the point:
EnsureCustomerExists(CustomerID)
EnsureDoorState(DoorStates.Closed)
EnsureUserInterface(GUIStates.Disabled)
Interesting question!
From the info that you have supplied, it seems to me that setstate (or simply set, if you are setting other things than states) would be fine, though ensure is good if you want to really emphasize the redundancy of an if.
To me it is however perfectly intuitive that setting a state does not throw an exception, or require an if. Think of setting the state of any other variable:
In C:
int i;
i = 5; // Would you expect this to throw an exception if i was already 5?
// Would you write
if (i != 5)
i = 5;
// ?
Also it only takes about one sentence to document this behaviour:
The function does nothing if the
current state equals the requested
state.
EDIT: Actually, thinking about it, if it is really important to you (for some reason) that the user is not confused about this, I would in fact pick ensure (or some other non-standard name). Why? Because as a user, a name like that would make me scratch my head a bit and look up the documentation ("This is more than just an ordinary set-function, apparently").
EDIT 2: Only you know how you design your programs, and which function name fits in best. From what you are saying, it seems like your setting functions sometimes throw exceptions, and you need to name a setting function that doesn't - e.g. set_missile_target. If that is the case, I think you should consider the set_if, set_when, set_cond or cond_set names. Which one would kind of depend on the rest of your code. I would also add that one line of documentation (or two, if you're generous), which clarifies the whole thing.
For example:
// Sets missile target if current target is not already the requested target,
// in which case it does nothing. No exceptions are thrown.
function cond_set_missile_target ()
or function cond_set_MissileTarget ()
or function condSet_MissileTarget ()
or function condSetMissileTarget ()
ensure is not so bad, but to me it implies only that there is additional logic required to set the state (e.g. multiple states tied together, or other complications). It helps to make the user avoid adding unnecessary ifs, but it does not help much with the exception issue. I would expect an ensure function to throw an exception sooner than a set function, since the ensure function clearly has more responsibilities for, well, ensuring that this setting operation is in fact done right.
I'd go for ensure for the function you describe. I'd also use camelCase, but I suppose you may be in a language that prefers underscores.
You could always document (shock!) your API so that others don't make the mistakes you describe.
First, i admit all the things i will ask are about our homework but i assure you i am not asking without struggling at least two hours.
Description: We are supposed to add a field called max_cpu_percent to task_struct data type and manipulate process scheduling algorithm so that processes can not use an higher percentage of the cpu.
for example if i set max_cpu_percent field as 20 for the process firefox, firefox will not be able to use more than 20% of the cpu.
We wrote a system call to set max_cpu_percent field. Now we need to see if the system call works or not but we could not get the value of the max_cpu_percent field from a user-spaced program.
Can we do this? and how?
We tried proc/pid/ etc can we get the value using this util?
By the way, We may add additional questions here if we could not get rid of something else
Thanks All
Solution:
The reason was we did not modify the code block writing the output to the proc queries.
There are some methods in array.c file (fs/proc/array.c) we modified the function so that also print the newly added fields value. kernel is now compiling we'll see the result after about an hour =)
It Worked...
(If you simply extended getrlimit/setrlimit, then you'd be done by now…)
There's already a mechanism where similar parts of task_struct are exposed: /proc/$PID/stat (and /proc/$PID/$TID/stat). Look for functions proc_tgid_stat and proc_tid_stat. You can add new fields to the ends of these files.