I am developing integration with Simperium, the integration is complete and has been running on test machines for sometime, I am starting to get this error on one of the devices and it keeps repeating constantly any ideas?
MeetingPad[891:1103] Simperium error (ActionLinks82), received an invalid change for (a18852011efe4964a6fdeb1853c790f3)
2013-02-07 10:07:05:277 MeetingPad[891:1103] Simperium client ios-7f43b434754d882923e966df5d885755 received change (ActionLinks82) ios-4176925448fa8ae0a2f1d0937627aa6b: {
ccids = (
3f3b4550b23147d49e194038feea09a6
);
clientid = "ios-4176925448fa8ae0a2f1d0937627aa6b";
cv = 5112df4b37a401031dcc5be1;
ev = 2;
id = 9ca0b7ad04314ab9888d75691be784b5;
o = "-";
}
If this occured on a user account what would be the guidance?
One thing to check is that you're using the latest version of the code. The repository was recently open sourced on GitHub. There used to be a bug related to nil values that could cause an invalid diff to appear in your change stream, but it should be fixed now.
Assuming you're using the latest code though, does the error repeat continuously for the same "id" value, or are there different values?
Looking at the Simperium code where this error occurs, it's possible it could be displayed if you've deleted an object locally and remotely at around the same time. In your app, might ActionLinks fit that pattern, i.e. are you creating and deleting a lot of them across multiple clients?
If that is indeed the cause, then the error is innocuous and we should patch the code. Let me know what you discover.
Related
I'm using AKRhodesPiano() and AkTubularBells(). Both work alone. When I try to initialize both, I get the following error.
AKRhodesPiano.swift:init(frequency:amplitude:):88:Parameter Tree Failed
Notably, if I change the order of initialization, the error occurs for the last one of the two instantiated.
Adding the following line to the AKTubularBells playground right under the initialization of AKTubularBells is enough to trigger the error.
let tubularBells = AKTubularBells()
let temp = AKRhodesPiano() /// <- Add this line.
I saw in another post AKRhodesPiano error (crush) on AudioKit v4.2 that there was a recent error in the STK Physical models, so perhaps this is part of that. Any insight appreciated as always.
Thanks for noticing this, it only occurred when using those two nodes simultaneously, but it was basically just a cut-and-paste job gone bad. I fixed it on develop, so if you can rebuild the framework you'll be fine or else wait for the next release which should be soon.
Here's the fix:
https://github.com/AudioKit/AudioKit/commit/05651ff97a7ea7815a27de6a53eee0b5f7998920
I am using C++ Builder XE7 VCL.
Around August 11 2016 2:00pm UTC, I started receiving multiple complaints from my user base about printing problems. Most of these printing modules have proven stable for many years, and there were no updates to my project within the past 24 hours. I was able to reproduce similar problems on my development/test environment.
Without going into many details of my project, let me present a very simple printing program that is failing:
void __fastcall TForm1::PrintButtonClick(TObject *Sender)
{
// Test Print:
TPrinter *Prntr = Printer();
Prntr->Title = "Test_";
Prntr->BeginDoc();
Prntr->Canvas->Font->Size = 10;
Prntr->Canvas->TextOut(300,1050,"* * * Printing Test * * *");
if (Prntr->Printing) {
Prntr->EndDoc();
}
}
On the first attempt to print, everything works perfectly as expected. If I click the button a second time, TPrinter produces a small PDF, but the PDF file is actually corrupted and appears to have a file handle stuck to it.
If I click the button a third time, I get no printing and the following error message appears:
Printer is not currently printing.
My own test was done using a PDF printer driver, but the complaints I am receiving from users include a variety of local printers, network printers, PDF printers, etc.
In my actual project, I have try/catch exception handling, so the actual results are slightly different, but substantially similar to this result. The results show the hallmarks of instability and/or memory leaks without much in terms of error messages.
I suspect there may have been some Microsoft Windows updates that are tangling with Embarcadero DLLs, but I have not been able to verify this so far.
Is anyone else having similar problems?
The reason using a TPrintDialog or TPrinterSetupDialog "works" to fix the error is because they force the singleton TPrinter object (returned by the Vcl.Printers.Printer() function) to release its current handle to a printer if it has one, thus causing TPrinter.BeginDoc() to create a new handle. TPrinter releases its printer handle when:
it is being destroyed.
its NumCopies, Orientation, or PrinterIndex property is set.
its SetPrinter() method is called (internally by the PrinterIndex property setter and SetToDefaultPrinter() method, and by TPrintDialog and TPrinterSetupDialog).
Without doing that, calling TPrinter.BeginDoc() multiple times will just keep re-using the same printer handle. And apparently something about the recent Microsoft security update has now affected that handle reuse.
So, in short, (without uninstalling the Microsoft update) in between calls to BeginDoc() you need to do something that causes TPrinter to release and recreate its printer handle, and then the problem should go away. At least until Embarcadero can release a patch to TPrinter to address this issue. Maybe they could update TPrinter.EndDoc() or TPrinter.Refresh() to release the current printer handle (they currently do not).
Therefore, the following workaround resolves the printing issue without requiring any changes to the user interface:
void __fastcall TForm1::PrintButtonClick(TObject *Sender)
{
// Test Print:
TPrinter *Prntr = Printer();
Prntr->Title = "Test_";
Prntr->Copies = 1; // Here is the workaround
Prntr->BeginDoc();
if (Prntr->Printing) {
Prntr->Canvas->Font->Size = 10;
Prntr->Canvas->TextOut(300,1050,"* * * Printing Test * * *");
Prntr->EndDoc();
}
}
There are no Embarcadero DLLs involved in printing. TPrinter simply calls Win32 API GDI-based print functions directly.
The "Printer is not currently printing" error occurs when one of the following operations is performed on a TPrinter when its Printing property is false:
TPrinter::NewPage()
TPrinter::EndDoc()
TPrinter::Abort()
a TPrinter::Canvas subproperty is being changed.
the TPrinter::Canvas is being drawn on.
You are performing half of these operations in the test code you have shown, but you did not specify which line of code is actually throwing the error.
The Printing property simply returns the current value of the TPrinter::FPrinting data member, which is set to false only when:
the TPrinter object is initially created (the Printer() function returns a singleton object that is reused for the lifetime of the executable).
the Win32 API StartDoc() function fails inside of TPrinter::BeginDoc() (FPrinting is set to true before StartDoc() is called).
TPrinter::EndDoc() is called when Printing is true.
So, given the test code you have shown, there are two possibilities:
StartDoc() fails and you are not checking for that condition. BeginDoc() will not throw an error (VCL bug?!?), it will simply exit normally but Printing will be false. Add a check for that:
Prntr->BeginDoc();
if (Prntr->Printing) { // <-- here
Prntr->Canvas->Font->Size = 10;
Prntr->Canvas->TextOut(300,1050,"* * * Printing Test * * *");
Prntr->EndDoc();
}
the Printing property is getting set to false prematurely while you are in the process of printing something. The only ways that could happen in the code shown are if:
random memory is being corrupted, and TPrinter happens to be the victim.
multiple threads are manipulating the same TPrinter object at the same time. TPrinter is not thread-safe.
Since you can reproduce the problem in your development system, I suggest you enable Debug DCUs in the project options, then run your app in the debugger, and put a data breakpoint on the TPrinter::FPrinting data member. The breakpoint will be hit when FPrinting changes value, and you will be able to look at the call stack to see exactly which code is making that change.
Based on this information, I am going to go out on a limb and guess that the cause of your error is StartDoc() failing. Unfortunately, StartDoc() is not documented as returning why it fails. You certainly cannot use GetLastError() for that (most GDI errors are not reported by GetLastError()). You might be able to use the Win32 API Escape() or ExtEscape() function to retrieve an error code from the print driver itself (use TPrinter::Canvas::Handle as the HDC to query). But if that does not work, you won't be able to determine the reason of the failure, unless Windows is reporting an error message in its Event Log.
If StartDoc() really is failing, it is because of an Win32 API failure, not a VCL failure. Most likely the printer driver itself is failing internally (especially if a PDF print driver is leaving an open file handle to its PDF file), or Windows is failing to communicate with the driver correctly. Either way, it is outside of the VCL. This is consistent with the fact that the error started happening without you making any changes to your app. A Windows Update likely caused a breaking change in the print driver.
Try removing the following Windows update:
Security Update for Microsoft Windows (KB3177725)
MS16-098: Description of the security update for Windows kernel-mode drivers: August 9, 2016
This appears to resolve the issue for several test cases so far.
It started happening here today too. On my Windows 10 setup this would happen after calling TForm's Print() 3 times. I tried both the Microsoft Print to PDF and the Microsoft XPS Document Writer and both gave the same error.
I did some quick debugging and found that it's the call to StartDoc() that returns a value <= 0.
A temp fix until I can figure out what is really causing this is to re-create the Printer object in Printers by calling
Vcl.Printers.SetPrinter(TPrinter.Create).Free;
after calling anything that is using the Printer object. Might not be advisable to do that, but it solved my issue for now.
Looks like something is not released properly when calling EndDoc()
It seems that this is really a Microsoft problem and they should fix this buggy update. You can find more info at this on the company site.
Using a Printer Setup Dialog is only a workaround, not real solution, for this Microsoft bug. After confirmation, the printer setup dialog always creates a new handle for the printer. The next one or two print jobs will then succeed.
The patch should come from Microsoft, not from Embracadero. Thousands of programs are affected and it would be a massive waste of time and money to implement a workaround in all of them, if there is a bug in MS update.
I started experiencing the same weird behavior at more or less the same time, when running 32 bit Delphi applications built in XE7 on a Windows 10 64 bit system.
After uninstalling the latest security upgrade for Windows 10 (KB3176493), printing from these applications works normally again.
A rather surprising side effect of uninstalling this update seems to be that the file associations - which are the default programs for handling specific file types - are being reverted to Microsoft Windows default values...
The following variation of the code in the question will resolve the problem, but requires a TPrinterSetupDialog component added to the form:
void __fastcall TForm1::PrintButtonClick(TObject *Sender)
{
// Test Print:
TPrinter *Prntr = Printer();
Prntr->Title = "Test_";
PrinterSetupDialog1->Execute();
Prntr->BeginDoc();
if (Prntr->Printing) {
Prntr->Canvas->Font->Size = 10;
Prntr->Canvas->TextOut(300,1050,"* * * Printing Test * * *");
Prntr->EndDoc();
}
}
For program usage, the user will be presented with the printer setup dialog before proceeding to printing.
As to "why", my best guess at this point is that TPrinter used alone does not have all necessary permissions to access all necessary resources from Windows after the Security Update for Microsoft Windows (KB3177725) was implemented on Aug 10, 2016. Somehow a call to TPrinterSetupDialog (or TPrintDialog) before calling BeginDoc() sets up the necessary conditions for TPrinter to perform successfully.
I have to create an application that has functionality similar to the contacts app. You can add a contact on the client's iPhone and it should get uploaded onto the client's iPad. If the client updates the contact on their iPad, it should get updated on their iPhone.
Most of this is fairly straight forward. I am using Parse.com as my back end and saving contacts locally with Core Data. The only problem I'm encountering is managing contacts when the user is offline.
Let's say I have an iPhone and an iPad. Both of them currently have the same version of the online database. My iPhone is now offline. It is 9AM.
At 10AM I update the phone number for a contact on my iPad. It saves the change locally and online. At 11AM I update the email address for the same contact on my iPhone but I'm still offline.
At noon, my iPhone connects to the internet and checks the server for changes. It sees that its changes are more recent than the latest update (checking an updatedAt timestamp property), so instead of downloading the new phone number for the contact (which is "obsolete"), it overrides the phone number along with the email address (updates the new phone number to the old version it has because it was offline during the phone number update at 10AM and its changes are supposedly more recent).
How am I supposed to manage the online/offline problems encountered such as the one above? A solution I can think of would be to keep updated timestamps on every attribute for a contact instead of just a general updatedAt property for the entire contact, e.g. when was first name updated, when was last name updated, and then manually check if an offline device has more recent changes on every attribute instead of overwriting the whole object, but that seems sloppy.
I was also thinking on having an updatedLocally and updatedOnline timestamp property on every Core Data object. This way if the two don't match I can do a diff-check and use the most recent one for conflicts but this still doesn't seem like the cleanest solution. Has anyone else encountered something similar? If so, how did you solve it?
Pseudocode/Summary for what I think? covers every test case but still isn't very elegant/complete:
2 Entities on Parse.com: Contact and Contact History
Contact has first, last, phone, email, onlineUpdate
Contact History has a Primary Key to a Contact to refer to and the same attributes but with history. e.g. first: [{value:"josue",onlineUpdate:"9AM"},{value:"j",onlineUpdate:"10AM"},{value:"JOSUEESP",onlineUpdate:"11AM"}]
1 Entity on Core Data, Contact:
Contact has first, last phone, email, onlineUpdate, and offlineUpdate (IMPORTANT: this is only on Core Data, not on Parse)
for every contact in parse database as onlineContact {
if onlineContact does not exist in core data {
create contact in core data
}
else {
// found matching local object to online object, check for changes
var localContact = core data contact with same UID as onlineContact
if localContact.offlineUpdate more recent than onlineContact.onlineUpdate {
for every attribute in localContact as attribute {
var lastOnlineValueReceived = Parse database Contact History at the time localContact.onlineUpdate for attribute
if lastOnlineValueReceived == localContact.attribute {
// this attribute did not change in the offline update. use latest available online value
localContact.attribute = onlineContact.attribute
}
else{
// this attribute changed during the more recent offline update, update it online
onlineContact.attribute = localContact.attribute
}
}
}
else if onlineContact.onlineUpdate more recent than localContact.offlineUpdate {
// another device updated the contact. use the online contact.
localContact = offlineContact
}
else{
// when a device is connected to the internet, and it saves a contact
// the offline/online update times are the same
// therefore contacts should be equivalent in this else statement
// do nothing
}
}
TL;DR: How are you supposed to structure a kind of version-control system for online/offline updates without accidental overwriting? I'd like to limit bandwidth usage to a minimum.
I would suggest to use key based updates instead of contact based updates.
You should not send the whole contact to the server, in most cases the user would just change a few attributes anyways (things like 'last name' usually don't change very often). This also reduces bandwith usage.
Along with the applied changes of your offline contact you send the
old version number/last update timestamp of your local contact to the server. The server can now
determine whether or not your local data is up to date, simply by looking at your old version number. If your old version number matches the current version number of the server there is no need for your client to update any other information. If this is not the case the server should send you the new contact (after applying your requested update).
You can also save those commits, this would result in a contact history
which does not store the whole contact each time a key was changed but only the changes themselves.
A simple implementation in pseudo code could look like this:
for( each currentContact in offlineContacts ) do
{
if( localChanges.length > 0){ // updates to be made
commitAllChanges();
answer = getServerAnswer();
if(answer.containsContact() == true){
// server sent us a contact as answer so
// we should overwrite the contact
currentContact = answer.contact;
} else {
// the server does not want us to overwrite the contact, so we are up to date!
}
// ...
}
} // end of iterating over contacts
The server side would look just as simple:
for (currentContactToUpdate in contactsToUpdate) do
{
sendBackContact = false; // only send back the updated contact if the client missed updates
for( each currentUpdate in incomingUpdates ) do {
oldClientVersion = currentUpdate.oldversion;
oldServerVersion = currentContact.getVersion();
if( oldClientVersion != oldServerVersion ){
sendBackContact = true;
// the client missed some updates from other devices
// because he tries to update an old version
}
currentContactToUpdate.apply(currentUpdate);
}
if(sendBackContact == true){
sendBack(currentUpdate);
}
}
To get a better understanding of the workflow I will provide an example:
8 AM both clients and the server are up to date, each device is online
Each device has an entry (in this case a row) for the contact 'Foo Bar' which has the primary key ID.
The version is the same for each entry, so all of them are up to date.
_ Server iPhone iPad
ID 42 42 42
Ver 1 1 1
First Foo Foo Foo
Last Bar Bar Bar
Mail f#b f#b f#b
(excuse this terrible format, SO sadly does not support any sort of tables...)
9 AM your iPhone is offline. You notice Foo Bar's email changed to 'foo#b'.
You change the contact information on your phone like this:
UPDATE 42 FROM 1 TO 2 Mail=foo#b
// ^ID ^old version ^new version ^changed attribute(s)
so now the contact in your phone would look like this:
_ iPhone
ID 42
Ver 2
First Foo
Last Bar
Mail foo#b
10 AM your iPad is offline. You notice 'Foo Bar' is actually written as 'Voo Bar'! You apply the changes immediatly on your iPad.
UPDATE 42 FROM 1 TO 2 First=Voo
Notice that the iPad still thinks the current version of contact 42 is 1. Neither the server nor the iPad did notice how you changed the mail address and increased the version number, since no devices were connected to the network. Those changes are only locally stored and visible on your iPad.
11 AM you connect your iPad to the network. The iPad sends the recent update
to the server. Before:
_ Server iPad
ID 42 42
Ver 1 2
First Foo Voo
Last Bar Bar
Mail f#b f#b
iPad -> Server:
UPDATE 42 FROM 1 TO 2 First=Voo
The server can now see that you are updating Version 1 of contact 42. Since version 1 is the current version your client is up to date (no changes commited in the mean time while you were offline).
Server -> iPad
UPDATED 42 FROM 1 TO 2 - OK
After:
_ Server iPad
ID 42 42
Ver 2 2
First Voo Voo
Last Bar Bar
Mail f#b f#b
12 AM you disconnected your iPad from the network and connect your iPhone.
The iPhone tries to commit the recent changes. Before:
_ Server iPhone
ID 42 42
Ver 2 2
First Voo Voo
Last Bar Bar
Mail f#b foo#b
iPhone -> Server
UPDATE 42 FROM 1 TO 2 Mail=foo#b
The server notices how you try to update an old version of the same contact.
He will apply your update since it is more recent than the iPad's update but
will send you the new contact data to make sure you get the updated first name aswell.After:
_ Server iPhone
ID 42 42
Ver 2 2
First Voo Voo
Last Bar Bar
Mail foo#b foo#b
Server -> iPad
UPDATED 42 FROM 1 TO 3 - Ver=2;First=Voo;.... // send the whole contact
/* Note how the version number was changed to 3, and not to 2, as requested.
* If the new version number was (still) 2 the iPad would miss the update
*/
The next time your iPad connects to the network and has no changes to commit it should just send the current version of the contact and see whether it is still up to date.
Now you have committed two offline changes without overwriting each other.
You can easily extend this approach and so some optimizations. For example:
If the client tries to update an old version of the contact, don't send them the whole contact as answer. Rather send them the commits they missed and let them update their contact by themselves. This is useful if you store lots of information about your client and expect few changes to be done between updates.
If the client updated all information about a contact we can assume he does not need to know about the missed updates, however we would let him know about everything he missed (but it would/should have no effect to him)
I hope this helps.
I know nothing about iOs, core data and parse.com, so I can suggest only a general algorithmic solution. I think you can an approach similar to what is done in version control systems.
The simplest thing is to keep all the history on the server: keep all the revisions of the contact list. Now during the synchronization the phone sends information about the last server revision it has seen, and this revision will be the "common parent" for both the current phone revision and current server revision.
Now you can see what has changed on server and on phone since that revision, and apply the usual 3-way comparison: if some field has changed only on the server, then send the new field to the phone; if some field has changed only on the phone, then change it on server too, if some field has been changed both on phone and on server and the changes are different, then you have a conflict and have to ask user.
A variation of this approach might be to work with changes, not revisions. The primary data at both the server and the client will be not the contact list, but a history of its changes. (The current contact list, as well as a set of 'keyframes' can also be kept if needed; it will not be used for conflict resolving algorithm, but can be used so that it can be quickly shown and used.)
Then, when a user synchronizes the data, you download/upload only the changes. If there are any conflict changes, you have nothing left but to ask a user, otherwise you just merge them. How you define a change and which changes are considered conflicting, is up to you. A simple approach can be defining a change as a pair (field, new-value), and two change are conflicting if they have the same field. You can also employ a more advanced conflict resolving logic such as if one change changes only the first half of the email, and the other the second half, then you can merge them.
The correct way to do this is to keep a transaction log. Whenever you save in Core Data you create a log entry in your transaction log. When you are next online you play back the transaction log against the server.
This is how iCloud and other sync services work.
Instead of having separate flag for each of the core data objects, you can have separate table which will store IDs(primary key from database table which stores contact information) of all updated contacts.
Later when user comes online you just fetch those contacts from your actual contact detail table and upload them on your server.
I am setting up an existing app in iOS6 to work with simperium, all has been going well for a few weeks but today I started seeing these errors.
I deleted the App in Simperium and started with a fresh app but still get the error.
The test case is an upgrade for an existing user who already has data in coredata. so they create the simperium account and this is the first sync simperium does.
2012-11-14 10:46:31:931 Simperium POST returned error 409 for change {
ccid = da3d0c7bed984f88872f9e7d7527f0f9;
clientid = "ios-ca84b5cc41cc00962c1141a2854aeee0";
error = 409;
id = 54f58c57de65485f889aa4b30c39c54b;
r = (
50a3760437a401650500001b
);
}
I also see some of these errors but not so many :
2012-11-14 10:44:52:823 Simperium error: transform diff for a ghost member (ghost <SPGhost: 0x1d6324c0>, memberData (null)) that doesn't exist (showInDropDown): {
o = "+";
v = 0;
}
Also this :
Simperium timeout, server didn't respond to GET code 504 (ClipModel82),
The 504 is an expected timeout. The other errors are not expected. 409 is a duplicate change, which is ignored but shouldn't happen. The transform error could be happening if you're making changes via a non-iOS client to an attribute that doesn't exist in your Core Data model.
A couple things to try: use the "iosupdate" branch that is on GitHub as of this writing. It has the latest changes and fixes. Also try setVerboseLoggingEnabled:YES and get in touch with us by email, including log output as an attachment (help#simperium.com).
FATAL ERROR: CALL_AND_RETRY_2 Allocation Failed - process out of memory
I'm seeing this error and not quite sure where it's coming from. The project I'm working on has this basic workflow:
Receive XML post from another source
Parse the XML using xml2js
Extract the required information from the newly created JSON object and create a new object.
Send that object to connected clients (using socket.io)
Node Modules in use are:
xml2js
socket.io
choreographer
mysql
When I receive an XML packet the first thing I do is write it to a log.txt file in the event that something needs to be reviewed later. I first fs.readFile to get the current contents, then write the new contents + the old. The log.txt file was probably around 2400KB around last crash, but upon restarting the server it's working fine again so I don't believe this to be the issue.
I don't see a packet in the log right before the crash happened, so I'm not sure what's causing the crash... No new clients connected, no messages were being sent... nothing was being parsed.
Edit
Seeing as node is running constantly should I be using delete <object> after every object I'm using serves its purpose, such as var now = new Date() which I use to compare to things that happen in the past. Or, result object from step 3 after I've passed it to the callback?
Edit 2
I am keeping a master object in the event that a new client connects, they need to see past messages, objects are deleted though, they don't stay for the life of the server, just until their completed on client side. Currently, I'm doing something like this
function parsingFunction(callback) {
//Construct Object
callback(theConstructedObject);
}
parsingFunction(function (data) {
masterObject[someIdentifier] = data;
});
Edit 3
As another step for troubleshooting I dumped the process.memoryUsage().heapUsed right before the parser starts at the parser.on('end', function() {..}); and parsed several xml packets. The highest heap used was around 10-12 MB throughout the test, although during normal conditions the program rests at about 4-5 MB. I don't think this is particularly a deal breaker, but may help in finding the issue.
Perhaps you are accidentally closing on objects recursively. A crazy example:
function f() {
var shouldBeDeleted = function(x) { return x }
return function g() { return shouldBeDeleted(shouldBeDeleted) }
}
To find what is happening fire up node-inspector and set a break point just before the suspected out of memory error. Then click on "Closure" (below Scope Variables near the right border). Perhaps if you click around something will click and you realize what happens.