[postgis-users] Tigerdata for AZ, AS and VI

[Ravi Ada]

Regina,

Thanks so much for the reply. I ran the missing_indexes_generate_script(),
actually it did not return anything, I am assuming all the indexes are in
place. That may be because I ran install_missing_indexes() earlier. I changed
the debug flag in geocode_address and it produced a very long query that it
runs to geocode the address. I tried to cut and paste the query to run the
plan, I am getting errors, I will figure that out.

My question is, do we use gecode or geocode_address for faster querying? I
noticed that geocode_address takes the normalized address where as geocode
takes address as string parameter. By adding additional normalize_address
function when doing the geocode_address akes it run any faster?


Thanks
Ravi Ada




On Wed, 14 Dec 2011 04:18:27 -0500, Paragon Corporation wrote
> > I just don't understand why the geocode function takes so 
> > long to return the coordinates. I am sure some of you on this 
> > list might have done the batch geocoding millions of 
> > addresses. I may be missing just a simple configuration which 
> > might make a whole lot of difference in the speed. I don't 
> > know what it is. I am following the examples exactly from this link
> > (http://postgis.refractions.net/documentation/manual-svn/Geocode.html)
> > 
> > If someone is familiar with the problem willing to help me 
> > using GoTo Meeting connection to my machine, I can arrange 
> > that too. I just have to move along with my project and meet 
> > the deadlines. I am already delayed, everybody in my team 
> > asking me for this everyday.
> > 
> > 
> > Thanks,
> > Ravi Ada
> > 
> > 
> Ravi,
> 
> Sorry been busy with raster stuff so haven't been tuned into this
> discussion.
> 
> 1) The indexes the loader generates are not the only ones needed.  Initially
> I was constantly changing the loader script,
> but since we were changing decisions as we changed code and optimal indexes
> needed with aeach change required changing indexes, which indexes 
> would be best, I created a function that would put them in rather 
> than bothering with the loader (since a lot of people would already 
> have their data loaded)
> 
> Have you tried running that.  I suspect you are just missing indexes 
> as the timings you are getting are what I used to get earlier on.
> 
> If you haven't run the update script (which runs this routine anyway)
>  or run this to get generated script for indexes you are missing you 
> should.
> 
> http://www.postgis.org/documentation/manual-svn/Missing_Indexes_Generate_Scr
> ipt.html
> 
> 2) There are a couple of other things to note: First address you do around
> an area can take a lot more time because of the data caching effects
> in postgresql.  So for the example in the docs you describe.
> 
> I can do a geocode of 75 State Street,Boston, MA  -- and if I 
> haven't done any geocoding in a while that takes like 1-3 seconds
> 
> Then if I do 80 State Street, Boston, MA -- that subsequent takes anywhere
> from 60 ms - 150 ms.
> I also don't have all the states loaded since I only needed it for 
> about 6 states.  thought that should just increase the planner time 
> rather than later times.
> 
> 3) For debugging performance there is a variable in the geocode_address
> function called var_debug.  Its false by default, change it to true.
> That spits out the sql being run and is a better sql to pass to the planner
> to check.
> 
> We were hoping to make these debugging features more publically 
> exposed e.g via a config table, but haven't had the time to do that.
> 
> Hope this all helps,
> Regina
> http://www.postgis.us
> 
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Thanks,
Ravi Ada
918-630-7381