Stefan Fuhrmann <stefan.fuhrm...@wandisco.com> writes: >> The original commit begins using svn_stream_wrap_buffered_read() during >> svnadmin load-revprops and svnfsfs load-index. This patch, however, does >> something entirely different and adds buffering to *every* stdin. > > Sorry for the confusion. I did not intend to actually change the > implementation of svn_stream_for_stdin this way but simply tried to > demonstrate a problem with APR buffer reads for "streamy" file handles.
Thank you for the explanation. > The underlying problem is still present: If stdin can't deliver data fast > enough (e.g. some hick-up / long latency on the producer side of a dump | > load), a buffered APR file will error out while a non-buffered one will > simply wait & retry. > > However, I have yet to try and provoke the error specifically for the > dump | load scenario. I think that this problem is nonexistent. A program doesn't need to handle EAGAIN during read() unless it puts the file into the non-blocking mode with O_NONBLOCK [1]. We don't do that for STDIN, and, irrespectively of what happens with the data on the other side of the pipe, read() is going to block until the requested data is available. [1] http://pubs.opengroup.org/onlinepubs/9699919799/functions/read.html Regards, Evgeny Kotkov
