Hi Frederik, thanks for the explanation!
The _replication_ diffs are the right choice if you want to update a full history file. Most people who update their OSM files on a regular basis do not need replication diffs, they are satisfied with the newest version of each object which has been changed. > So, if you want to use daily diffs but avoid the danger of missing > edits, use the replication diff. Very good advice. Until today I chose NOT to use the diffs in the planet.openstreetmap.org/history/ directory because they are outdated. They usually come with a delay of 25 hours. Du you know if the creation process could be accelerated somehow? Now I will attend to osmupdate and try to change from daily normal diffs to daily replication diffs. Seems to be better than loosing objects once in a while. Meanwhile people can use Osmosis, or run osmupdate with the --hourly option which will restrict the program to replication diffs. Markus -------- Original-Nachricht -------- > Datum: Sat, 05 Nov 2011 22:56:01 +0100 > Von: Frederik Ramm <frede...@remote.org> > An: dev@openstreetmap.org > Betreff: Re: [OSM-dev] Incomplete diffs? > Hi, > > On 11/05/2011 06:58 PM, mar...@gmx.eu wrote: > > Meanwhile I found out that this node simply did not appear in the daily > diffs: > > http://www.openstreetmap.org/browse/node/1470178889 > > > > It was crated at 2011-10-16T23:58Z by a large changeset along with > 23.000 other nodes. > > Neither the 16/17 nor the 17/18 daily diff contain this node whereas the > hourly diff from October 17 01:00 does. > > There are two types of diffs; "replication diffs" and normal diffs. A > replication diff contains everything that happened between two > timestamps, including multiple changes of the same object, whereas a > normal diff only contains the information required to get from state 1 > to state 2. > > Also, replication diffs are created in a relatively fail-safe process > with Osmosis whereas the normal diffs can miss changes in some cases > when a long-running database transaction that was created before 0:00 > extends past the time when the diff is created. (There was a time when > we had only "normal" diffs, and it was near impossible to make sure the > minutely/hourly ones did not miss anything.) > > For minutely and hourly diffs, we only offer replication diffs these > days. For daily diffs, we have the normal ones under > planet.openstreetmap.org/daily, as well as the replication diffs under > planet.openstreetmap.org/history. > > The normal diff indeed lacks the node in question, but the daily > replication diff under history/2011/1016-1017.osc.gz has it. > > So, if you want to use daily diffs but avoid the danger of missing > edits, use the replication diff. > > Frankly I don't know why the normal daily diffs are still created at > all; if one really wanted to offer a reduced-traffic version of the > replication diffs then it would indeed make sense to simply deflate the > replication diff using Osmosis' --simplify-change task. > > Bye > Frederik > > -- > Frederik Ramm ## eMail frede...@remote.org ## N49°00'09" E008°23'33" > > _______________________________________________ > dev mailing list > dev@openstreetmap.org > http://lists.openstreetmap.org/listinfo/dev _______________________________________________ dev mailing list dev@openstreetmap.org http://lists.openstreetmap.org/listinfo/dev