chunked uploading iOS

When using chunked upload instead of single request uploading, there's extra overhead, due to the additional requests that need to be made. So, while it should be more reliable (i.e., less likely to timeout), it can take longer.

You can optimize this compromise for your scenario by choosing your chunk size (i.e., how much data you send per request) carefully. Larger chunks will reduce the overhead, but will be more likely to time out on uploading any particular chunk. Smaller chunks are less likely to time out, but introduce more overhead.

The iOS Core SDK uses a chunk size of 2 MB, and unfortunately doesn't expose a way to set a custom size though. (I'll consider this a feature request, however.) The SDK is open source though, so you can add the source directly and modify it if/as desired. The chunk size is passed to readDataOfLength in the uploadFileChunk in DBRestClient.m.