Resumable Synchronization with UltraLite DB on IPAD Failing with Error -1103

[Former Member]

Hi All,
I am trying to achieve resumable Sync feature provided in UltraLite C++ API for IPAD. I am getting an error -1103(SQLE_Partial_Download_Not_found). My approach is like this:-
1.Initialize the ul_sync_info struct object say myStruct with keep_partial_download option YES.
2.Initiate the Sync for publication say PUB1.
3.Now disconnect the VPN network so that Sync will fail with a communication error.(and i am doing it during download phase as documentation specifically said that if Sync fails during download it will set the retain_partial__download_ option to true.)
4.Now restart the Sync again. I am checking whether last sync was successful OR failed. 5.As Sync got failed last time i am setting the option resume_partial__download_ to YES.
@Observations :- I have verified the contents of myStruct and after sync failure it is setting the retain_partial__download_ parameter to YES.

Now in this case Sync is failing with 1103 error code every time. I have tried with altering the combination of these two parameters to YES/No also but all failed.I have checked the documentation thoroughly but couldn't come up with any other solution. Please guide me if i am doing something wrong or missing any step.

[Former Member · Accepted solution]

Hi All,
It's been a hectic period while cracking this issue and the solution itself is like that there was no problem at all. I don't know the abstract details of Resumable Sync functionality, but i will share my understanding here, which gave me a solution.

1. A connection object holds the partial download data if sync got failed(of course keep partial download option is true)
   

2. If you close the connection partial download data will be gone.

   So here are the steps to do a resumable sync: -

   A) Start the sync by providing all mandatory ul sync info parameters along with the below mentioned setting.

   myStruct.keep_partial_download = ul_true;
   

B) When sync got failed, restart the sync again with all mandatory input parameters along with below mentioned setting.

     myStruct.keep_partial_download = ul_true;
     myStruct.resume_partial_download = ul_true;

[jeff_albion]

Resumable downloads also rely on the MobiLink server having enough space to cache the download (and being requested before the information is replaced in the download cache by other remote requests).

How big is your remote download stream and how is the MobiLink server currently configured for resumable downloads? Specifically, how big is the resumable download cache (mlsrv12 -ds)? The default is 10M.

[Former Member]

We are using 20M size for resumable download cache.
One more observation i would like to share which i tried yesterday:-
1.set keep partial download option true and do a sync and terminate it during download process.We are doing Sync here from Sybase Central tool not from the XCode.
2.Now set continue download option true(we didn't set resume partial download option) and start the Sync. Sync started from the point it got failed and completed successfully.
3. But we don't have an option continue download in ul sync info struct. I tried to gave this option in additional_params, but no success. It showed error -1002(Invalid Option)

[Former Member]

Sorry, i haven't checked the list for additional parameters available for use before attempting it. I got it now, continue download is not a valid option in addtional params field, which explains the error -1002.

[philippefbertrand]

In step 4 are you reconnecting the VPN network?

When resuming a partial download in step 5, it is important that you use the same publications plus resume_partial_download. You may also choose to keep the keep_partial_download option on.

Are you changing any other options between syncs such as download_only, user_name, etc?

[Former Member]

Yes i am reconnecting it,otherwise Sync won't happen.
I am using same publication with resume_partial_download and keep_partial_download options TRUE.
No, no other option is getting changed from code. all i am doing is just setting above mentioned options to TRUE along with the old settings of userName,password,version info,streamParams etc.