[OSM-dev] [OSM-talk] Deleted Place names in the Philippines

[Andy Robinson (blackadder)]

Moved to dev

Tom Hughes wrote:
>Sent: 17 January 2008 8:34 AM
>To: Ian Haylock
>Cc: talk at openstreetmap.org; Richard Fairhurst
>Subject: Re: [OSM-talk] Deleted Place names in the Philippines
>
>In message <170535.42823.qm at web27211.mail.ukl.yahoo.com>
>        Ian Haylock <haylocki at yahoo.co.uk> wrote:
>
>> Tom Hughes <tom at compton.nu> wrote:
>>
>> > All edits are logged against the user id of the uploader anyway, so
>> > that doesn't gain you anything
>>
>> Is this true with potatch as well ?
>
>Yes.
>
>> Just curious, but what would be involved in undoing someones edits
>> in the database ?
>
>Well the first problem is finding them - there are a lot of objects
>in the database and there are no indexes on the user so finding edits
>by a given user is hard to start with.
>
>> i.e. suppose I deleted a way, then uploaded the edit to the database.
>>      Does sql delete all the data for the way in the database ? Or
>>      just mark the data as deleted ?
>
>In the case of a delete the object is marked as deleted in the live
>table and a new record is added to the history table marking the
>object as deleted.
>
>To answer your question more generally, all edits are recorded in a
>set of history tables so no data is lost as such. It's just not very
>easy to find and restore.
>


I think it could be argued that the history information is of little use
unless it can be easily used. Is changeset rollback the only major use of
the history information we anticipate or should there be other indexed
options? That's an open question rather than directed at Tom specifically.

Cheers

Andy