[OSM-dev] Minute Diffs Broken

openstreetmap-dev at scd.debian.net openstreetmap-dev at scd.debian.net
Tue May 5 02:21:06 BST 2009


In article <49FF86A3.8060408 at remote.org> frederik at remote.org wrote:
>Thinking about possible solutions:
..

>3. Make a semantic change to the way we handle diffs: Let the diff for 
>interval X not be "all changes with timestamp within X" but instead "all 
>changes that happened in a changeset that was closed within X". 
>Changesets not being atomic should pose no problem for this (because 
>when it's closed, it's closed). This would adversely affect downstream 
>systems in that some changes are held back until the changeset is closed 
>(whereas they are passed on immediately now), but on the other hand you 
>could afford to generate the minutely diff at 5 seconds past the minute 
>because you do not have to wait for transactions to settle (the actual 
>changeset close never happens inside a transaction).

Would this work?

How about the situation:

Changeset A creates a node

Changeset B uses the node in a way

Changeset B closes

(Later) Changeset A closes


If the create is delayed until changeset A closes, then B has a way with
an uncreated node.


Trapi depends on all nodes in a way existing to determine what tiles
to place the way in, and all members of a relation to place the
relation in tiles.  (There are some situations where the later isn't
true, so some relations may be missing from some tiles in Trapi.)
-- 
Blars Blarson			blarson at scd.debian.net

With Microsoft, failure is not an option.  It is a standard feature.




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