On Thu, Jun 26, 2003 at 04:31:29PM +0200, [EMAIL PROTECTED] wrote: > > If i recall correctly (i've not gone back to review that > > patch) that patch required whole-file transfers two avoid s/two/to/ #ick > > doing the operation twice per file. If the filter is > > deterministic and particularly if changes have minimal > > cascade effect you may be able to still take advantage of > > the rsync algorithm. > > You recall correctly. > It is not clear to me how using "whole-file" and still take advantage of > the rsync algorithm.
You meant "how to use"? The --whole-file option disables the rsync algorithm. > The idea of this patch seem to me very useful. > I'm plan to use it with the "rsyncable" gzip version > (http://svana.org/kleptog/rgzip.html). > The "whole-file" is not necessary is this case. I think that the patch need > to be modifiy so that > whole-file will be a option. If the receiver does the filtering whole-file is necessary. To show why i will describe what it takes if the receiver does the filtering without whole-file assuming gzip is the filter. gunzip to temp file to generate block checksums.* delete temp file. ---- interval when other files may be processed ---- gunzip to temp file* again and merge file with blocks from sender. delete temp file. gzip resultant file. Notice that this also requires a reverse filter. If the filtering is done on the sender. gzip file to temp.* match blocks or send whole gziped file to receiver. delete temp file. Observe the sender-side only requires a forward filter. *The temp file is needed because match and block checksumming use memory mappings of the file so i don't think it is capable of reading from a pipe. Merging even does seeks because matched blocks may be out of order. Whether the rsync algorithm is useful depends on the determinism and change-cascade effects of the filter. A ignore-size option would have to be created to deal with filters that alter the file length. The --checksum option would be best not used as it would require every file be filtered during flist generation and then changed files filtered again for sending. -- ________________________________________________________________ J.W. Schultz Pegasystems Technologies email address: [EMAIL PROTECTED] Remember Cernan and Schmitt -- To unsubscribe or change options: http://lists.samba.org/mailman/listinfo/rsync Before posting, read: http://www.catb.org/~esr/faqs/smart-questions.html
