Hi, >> The very reason for having changesets is to do some grouping and >> filtering on the server side, instead of having to let the client do >> everything (and incur a lot of server load and traffic along the way). > > I thought the reason for changesets was to have some grouping > so we could do rollback.
We could do rollback even now without any grouping, but it would incur a much higher server load than with convenient change group access. > I was not aware this is also a server > load issue. And frankly if this is about server load then there > are better ways to mitigate that like rewriting the map call as > a C/C++ apache module... The map call is not involved. >> And not: "During changeset 123, the user first idled for 10 minutes, >> then moved node A a bit further north, five minutes later moved it back >> south, then decided to add a tag; subsequently deleted the whole node >> and repeated the procedure with a new one...". This is completely >> unnecessary and only confusing for any clients who want to work with the >> changeset data. > > Mm. I have a difficult time picturing the difficulty for the > client. Use your imagination then. If the user requests, say, a graphical representation of the changes effected by change set X, you will not want to show the intermediate steps. So you would have to collapse the change set - something changed first and deleted later, show it only as deleted; something created at position A and moved to position B, show it as created at position B; something moved from X to Y and then from Y to Z, show it as moved from X to Z. This collapsing would have to be implemented in every piece of software that deals with changesets, and my hunch is that everybody would implement it slightly differently. Thus I want it in the server. > On the contrary my hunch feeling is that rollback is going > to be easier, more flexible and more robust if the changeset is not > mangled but is presented as small piecewise changes. Au contraire. Rolling back a changeset requires the very same collapsing; if the changeset contained a change from X to Y to Z, then you want to rollback from Z to X and not from Z to Y to X. Bye Frederik _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/dev
