[Twisted-Python] Large Transfers

Uwe C. Schroeder uwe at oss4u.com
Sat May 10 11:20:37 EDT 2003

You're right, it doesn't. However it still requires several calls to transfer 
the whole set. :-( And it has another problem. The pager makes it hard to 
give the user some response while uploading/downloading. The UI gets stuck, 
or at least appears to be since nothing is happening.
Basically I think pb should start paging whenever the argument list exceeds a 
certain size. I have no idea if paging is really neccessary, but I could 
think of some problems with blocking twisted while a non-paged transfer is in 
progress. This certainly depends on how the underlying transport is 
implemented. I'll do some tests with a modified twisted version and see if it 
gets too slow if a bunch of large transfers are in progress.

On Saturday 10 May 2003 07:38 am, Andrew Bennetts wrote:
> On Sat, May 10, 2003 at 06:59:16AM -0700, Uwe C. Schroeder wrote:
> [..snip..]
> > What I'm doing is to hand down XML data which is database-generated on
> > the server side. Whenever a user requests a too large resultset the
> > network layer fails. On the other hand the resultset already is in
> > memory, so why not jut transfer it ?
> > I realize that his is probably bad design, but it's the easiest way to
> > transfer this information. Sure I can write the stuff to a temporary file
> > and page it over, however this defies the purpose, since then the
> > original call results in a message to go get the file. This means I need
> > at least 4
> The PB paging support doesn't require you to write out to a file, look at
> e.g. twisted.spread.pb.util.StringPager, the implementation is quite
> simple.
> Does this solve your problem?  (I'm not a PB expert, so I can't really
> answer your questions in depth).
> -Andrew.
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