News on 4.8.1 Syncing Bug

[dhaupert]

Hi all,

I've finally been able to duplicate the hanging sync on my machine. I tried with many databases in the size range of 200-500KB and they always transferred just fine. I got it to happen with a 730KB database and realized that the size limit before the problem differs depending on the user.

For those that are curious what is going wrong, the system log reports this error:

Error while sending response (/DatabaseName.PDB -- http://192.168.0.175:8080/): *** -[NSConcreteFileHandle writeData:]: Resource temporarily unavailable

This doesn't happen with a device running iOS4 with the latest builds, only iOS5. I did some research on this error and there are others who are having problems with iOS5 and the NSFileHandle networking methods, which is the method I implemented to do a web server in HanDBase since the first iPhone build. Apparently while there is an issue with this suddenly failing, Apple's response has been to switch to using a different networking protocol that works better. This is frustrating, there is a lot of code that has been written to design and embed an HTTP server in the app and now I have to rewrite much of it. It also means that something that has been stable and reliable in the past will need lots of testing and tweaking.

I'm quite worried about this to be frank, but I am trudging forward with investigating and beginning the work. Unfortunately it does not appear that I'll have any quick fix to offer to you on this. Very sorry to report this and I will post updates to this thread as I make progress...

[Brian_Houghton]

Hi, Thanks for the status update!

Sent from my SCH-I500 using Tapatalk

[Dlevymd1]

Other programs, such as iFiles and Fileapp, have the same desktop connect with WiFi function and did not have an issue with the IOS5 upgrade. Maybe there is a easy solution. I hope so!!!
Dan

[dhaupert]

Dan,

They probably implemented their Desktop Connect mode using a different protocol like I mentioned above. There are often many ways to accomplish the same thing in programming. I chose one path and they likely chose another. There are developers posting to the private Apple boards with this same problem so I'm not alone with this issue!

[dhaupert]

Here's an update on my progress...

I have been working on implementing a whole new set of communications libraries into HanDBase's Desktop Connect mode. This is a huge change to the program, but I'm grudgingly making it. The Apple developer I spoke to suggested doing this as opposed to waiting for any future iOS5 update that fixed the bug I'm encountering in one particular communications (socket) call.

Candidly my hope is that I will be able to finish the development of this by the end of the week. No promises there, and there will then need to be much testing done here to verify it all works reliably, but that is what I'm shooting for.

I'm about to stop working for the night but wanted to share that I have the new library running within HanDBase ahead of schedule! It is not complete, but does all the file downloading stuff. On top of that, it works with large files as well, which is a huge relief. Of course, download is only half of the direction needed to fully support desktop connect so tomorrow I will start on the second half. If I have as successful a day tomorrow as today I'd be several days ahead of schedule and ready to start testing! Here's hoping...

I'll let you know how things progress. Thanks so much for your patience with this issue and with me in particular. You are all the greatest customers in the world!!

[ArGiEs]

Dave,

Thanks so much for your communication. Keep up the good work!

Regards,
Bob

[Max]

Here's an update on my progress...

I have been working on implementing a whole new set of communications libraries into HanDBase's Desktop Connect mode. ... I'll let you know how things progress....

We all appreciate your hard work, Dave, and understand the fix that Apple has put you in. In the meantime, let me see if I understand what's going on--because I'm eager (otherwise) to upgrade my iPhone to iOS 5.

So HanDBase 4.8.1 runs okay in iOS5, right? But there are (or may be) problems when syncing large databases on some iPhones. Transferring data by email is a workaround. What I'm not confident about is database integrity: Can this problem corrupt databases? If so, how can we protect against it--just not sync at all until your new version comes out?

[Brian_Houghton]

Hi Max,

You are perfectly okay to email and / or use iTunes' file sharing to manually move databases between your computer and handheld. This definitely shouldn't result in any file corruption.

The one issue you might see is that databases using calculated fields aren't opening properly. You could either manually disable the calculated field in HanDBase Desktop prior to installing OR roll back to version 4.8.0 of HanDBase, using it on iOS 5.

[dhaupert]

Here's today's update. Been working on the upload capability which is divided into two parts- the upload from Desktop Connect via a browser and the upload via the conduit. After spending the entire day debugging an issue with Multi-part encoding of messages in the new library I finally got it working for the browser side, and I'm now uploading all sorts of things to test. I still have the Conduit upload to work on and will start on that tomorrow.

But I did find a problem which is very disconcerting- I uploaded the database that failed for me with the other library (a 750KB database file). It uploaded just fine and opened fine, but when I try to download it, it stops at exactly 512KB No errors or exceptions, just seems to stop sending at that point. I'm pretty frustrated about it but hope to be able to find a solution. I'll keep you posted!

[dhaupert]

But I did find a problem which is very disconcerting- I uploaded the database that failed for me with the other library (a 750KB database file). It uploaded just fine and opened fine, but when I try to download it, it stops at exactly 512KB No errors or exceptions, just seems to stop sending at that point. I'm pretty frustrated about it but hope to be able to find a solution. I'll keep you posted!

Good news about this one- was a bug that I just found and fixed, so now it seems to download large files just fine. Still lots of testing and completion to do but things are looking good! Hope to be in testing before the week is over..