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The Java XAPI

Ievietoja iandees @ 26 janvārī 2011 iekš English

I recently released the first version of a mostly-complete Java implementation of the XAPI server. The source code is available on my GitHub with a readme describing generally how to get it set up.

Running this database with a full-planet requires some large, fast disks. The database is roughly 350GB and is slowly increasing:

CPU and memory usage are useful for the initial import (indexing especially), but any subsequent queries will be limited by the disk speed.

Feel free to use it! Serge W. created an XAPI UI framework that I set up at http://openstreetmap.us/uixapi/xapi.html to build the XAPI query URLs.

At the moment, the Java XAPI seems to have a problem returning relations and doesn't implement child element predicates or special tags. If you find other problems, please file a bug.

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Discussion

Komentārs no Firefishy @ 26 janvārī 2011 @ 15:13

Stats for xapi.osm.org for 25 Jan 2011:
tags:
@user= - 27 queries from 12 IP addresses.
@uid= - 3 queries from 2 IP address.
@changeset - 1 query

Komentārs no Harry Wood @ 26 janvārī 2011 @ 16:00

You didn't actually mention the base URL for your new service: http://openstreetmap.us/xapi/api/0.6/

It works! Example: All the libraries in London : http://openstreetmap.us/xapi/api/0.6/*[amenity=library][bbox=-0.57,51.24,0.31,51.75]

Great work!

Komentārs no Tom Chance @ 26 janvārī 2011 @ 16:24

Great, I'll give it a go.

Komentārs no Maarten Deen @ 26 janvārī 2011 @ 16:37

Looks promising. But the performance with large bboxes isn't there yet.
Harry Wood's example works for me, I can also download banks in a 0.2x0.2 bbox, but trying to get banks for the whole of the Netherlands does not work yet. I get a "504 Gateway Time-out" message.
My test URL: http://openstreetmap.us/xapi/api/0.6/*[amenity=bank][bbox=2.5,50.7,7.2,53.6]

Komentārs no iandees @ 26 janvārī 2011 @ 16:42

The machine restarted itself at 16:00UTC or so, which lines itself up with your request fairly well.

But yes, large bounding box queries are mildly slow -- I don't remember them being particularly fast on the other system, though.

Komentārs no Tom Chance @ 26 janvārī 2011 @ 16:48

I get the same message trying to download all power generators in the UK.

http://openstreetmap.us/xapi/api/0.6/*[power=generator][-6.5,49.68,2.67,61.31]

Just London works fine:
http://openstreetmap.us/xapi/api/0.6/*[power=generator][bbox=-0.5
1,51.20,0.35,51.80]

Komentārs no iandees @ 26 janvārī 2011 @ 16:53

It bounced a few more times and is down hard now. There appear to be some ECC memory errors, but I put fresh memory in a while back. Looks to be a bad motherboard. Thanks for the stress test, everyone!

Komentārs no Geonick @ 27 janvārī 2011 @ 23:13

Is this XAPI UI really reflect the syntax of XAPI? Currently there is only one tag predicate. Isn't it possible to query more than one, like

http://openstreetmap.us/xapi/api/0.6/*[amenity=parking][capacity:disabled=*][bbox=-0.57,51.24,0.31,51.75]

Actually, even the OSM wiki leaves this question open:
osm.wiki/Xapi#Predicates

It would be nice anyhow that the wiki page get's enhanced with a real syntax definition.

Komentārs no iandees @ 28 janvārī 2011 @ 01:24

@Geonick: yes, this really does follow the XAPI query syntax. You can indeed supply multiple tag predicates. It will eventually be possible to include multiple bounding box predicates, but at the moment I only allow one.

Komentārs no Katzman @ 9 martā 2011 @ 21:01

Two things:
- so the possibility to enter multiple tags is not implemented yet, right?
- is it possible to do non-case sensitive search on the values, such as icao=lklt would return any combination of LKLT, lklt, LKlt, LkLt, etc.?

Thanks!

Komentārs no iandees @ 9 martā 2011 @ 21:03

@Katzman:

1. It is possible to enter multiple tag predicates:

[amenity=foo|bar] := "amenity"="foo" OR "amenity"="bar"
[amenity|leisure=foo] := "amenity"="foo" OR "leisure"="foo"
[amenity=foo][area=bar] := "amenity"="foo" AND "area"="bar"

2. Not at this time.

Komentārs no Arminus @ 21 martā 2011 @ 19:34

Very nice ! Any updates on the relation problem ?

Komentārs no Tilo @ 31 martā 2011 @ 17:45

Is the jxapi down at the moment?

I want to prevent denied download requests before the request is sent. How is it handled, if a bbox is too large? like this?
[bbox=West,South,East,North]
if difference(West,East)*difference(South,North) > 10 --> denied
if difference(West,East)*difference(South,North) <= 10 --> accepted

Is it planned to allow larger bboxes than 10 sqaredegrees in future?

Thanks!

Komentārs no Tilo @ 31 martā 2011 @ 17:48

[bbox=West,South,East,North]
if difference(West,East)*difference(South,North) > 10 --- denied
if difference(West,East)*difference(South,North) <= 10 --- accepted

Komentārs no iandees @ 31 martā 2011 @ 17:51

@Tilo: No, the jxapi is/was not down. It was getting inundated with duplicate requests so the process queue was very long. I restarted postgres to clean out the queue.

I compute the sum of the areas of the requested bounding box(es) and compare that to 10. If larger, 500. If less, let it through.

There are no plans to do areas larger than 10 square degrees. As you can see already the hardware has a hard enough time keeping up.

Komentārs no Tilo @ 31 martā 2011 @ 17:51

damn,
the third line was supposed to look like this (now, in words):
if difference(West,East)*difference(South,North) is less or equal 10 then accepted

Komentārs no Tilo @ 31 martā 2011 @ 17:59

Great! thanks a lot.

Komentārs no Tilo @ 1 aprīlī 2011 @ 04:36

I just tested a little smaller request than 10 square degrees with the request below (9.8 sqdeg) and ran into an Error. see the message below from http://jxapi.openstreetmap.org/xapi/admin/stats

ERROR way[boundary=administrative][bbox=8,48,10,52.9] 144 30 mins 32.909 secs

What is wrong with the request? Is there another reason for denial than the bounding box?

Thanks

Komentārs no Tilo @ 1 aprīlī 2011 @ 05:12

this worked:
way[boundary=administrative][bbox=8,48,10,52] (221655 elements)

but this didn't:
way[bbox=8,48,10,52]

???

Komentārs no malcolmh @ 5 aprīlī 2011 @ 09:44

Bounding boxes that straddle 180 E/W are rejected. I assume this is because West > East. Is this a bug or a feature?

Komentārs no iandees @ 5 aprīlī 2011 @ 10:47

This is not a good place to make bug reports. Do that here: https://github.com/iandees/xapi-servlet/issues

Komentārs no iandees @ 12 aprīlī 2011 @ 20:05

********THIS IS NOT A GOOD PLACE TO MAKE BUG REPORTS************. Do that here: https://github.com/iandees/xapi-servlet/issues

Komentārs no Langlaeufer @ 17 aprīlī 2011 @ 12:36

sorry, I do not like to register there!

Komentārs no Bryce C Nesbitt @ 27 aprīlī 2011 @ 06:59

Great! Thanks for making progress brining xapi back to life!
It would be nice if the status page at http://jxapi.openstreetmap.org/xapi/admin/stats gave details on the ERROR, rather than simply saying ERROR.

Komentārs no Tilo @ 28 aprīlī 2011 @ 02:51

I agree with Bryce on both!

about 14 days ago this request: *[bbox=8.173,49.815,9.173,50.554] worked fine.
size 523 MB

Yesterday in the afternoon and today (at night) I always got an error. I tried 5 times each. Neither the bbox limitation of 10 sqare degrees (less than 2 sqdeg here) nor the syntax should be a problem in this request. What are the other limitations which cause an error?

Have new limitations been implemented between apr,14 and apr,28?

Komentārs no iandees @ 28 aprīlī 2011 @ 02:52

********THIS IS NOT A GOOD PLACE TO MAKE BUG REPORTS************. Do that here: https://github.com/iandees/xapi-servlet/issues

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