Pre-Filter and rebuild of current tables #3796
Comments
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Author: brett[at]bretth.com Hi Mikey, It appears in case that you're using the apidb schema. This schema does not support efficient large-size bounding box queries. The API allows small bounding box downloads (via the /map) call, but the maximum size is severely constrained. Efficient large bounding box queries require a purpose-built schema like the pgsnapshot schema. In short, pre-filtering of areas will never be supported by Osmosis for the apidb schema. As to the second part of your request, I'm not clear on what you're trying to do. If you want the entire planet in the history tables but only your province in the current tables then it seems that you're trying to use the schema for something which it isn't originally intended. There's nothing wrong with that, but adding special code to Osmosis to support your specific use case is not something I'm willing to do. If you really want that you'll have to code and maintain your own Osmosis extensions. I'd prefer any further discussion on this to take place on the mailing list. Brett |
Reporter: MikeyCarter
[Submitted to the original trac issue database at 6.44am, Wednesday, 1st June 2011]
This is somewhat of a dual ticket, one problem is creating the second situation.
I've loaded all of Ontario, Canada, but have been pulling in all updates from replication so after 1 1/2 years of data I've got most of the world.
If I want to pull just Ontario data it seems to query the entire world, then filter. It would be nice to have the filter applied at the sql read level so it doesn't have to read the entire database.
The second part to this ticket, my current work-a-round is to delete all but Canada from the current_* tables, that way I'm not pulling the world before the prefilter. That way I have a much smaller set to work from. (while the history is still intact in the other tables)
However, would be nice if there was a way osmosis could rebuild the current_* tables. (in part or as a whole) That way every once and a while I could apply the province filters to osmosis and rebuild.
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