[postgis-users] GIST INDEX!!

[Chris Hermansen]

César;

You need to be a bit more specific about what you mean by "slow".  What
operations precisely are slow?

Having said that, in general any columns - spatial or otherwise - to
which you refer in WHERE clauses in your SELECT statements should be
considered for indexing, especially if you use them in join conditions.
If you have a specific SELECT statement that gives you problems, you
might try using an EXPLAIN or ANALYZE together with the statement as for
example in

http://www.postgresql.org/docs/8.1/static/sql-explain.html

2700 tables - that is a lot of tables.  I have no idea if such a large
number of tables will slow down query execution, but it seems possible.

Do you really need that many tables?  For example, if you have all the
IGM shape files by map sheet for loading, you don't need to create a
table for each shape file.  Rather you might put all the different
"caminos" shape files into one table, and the "comunas" into another,
and so on.  Sorry I'm just guessing at what you might be doing here, if
I'm wrong please ignore!

La documentación de PostgreSQL es disponible en castellano, por ejemplo
en el sitio

http://palomo.usach.cl/docshtml/node4.html

On Tue, 2009-12-29 at 15:38 -0300, César Medina wrote:
> Dear all
> 
> 
> I am trying to do a tunning to my database, and i have many doubt,
> because i think that is very slow (with 3 o 4 users is slow)
> 
> 
> I have 2700 tables aprox. with geometry column in my database, the
> street's name, big avenues, regional boundaries, street types,comunal
> areas, etc. but the tables don't have a index in the geometry
> column !!!!!!! - Is recommended do a "GIST" index for each tables in
> my database? - Could be more fast, if that have a gist index? - What
> is the benefits ? kings regards, thank you... and happy new year.
> 
> 
> PD: Frecuently i do "vacuum" and "reindex" to my database
> César http://www.linkedin.com/in/cesarmedinam
> http://foss4gchile.blogspot.com/ mail: ciesareMedina (at) gmail (dot)
> com msn: ciesareMedina (at) hotmail (dot) com skype: ciesare_medina
> 
> CHILE.
> 
> 
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-- 
Regards,

Chris Hermansen    ·    mailto:chris.hermansen at timberline.ca
tel+1.604.714.2878 · fax+1.604.733.0631 · mob+1.778.840.4625
Timberline Natural Resource Group · http://www.timberline.ca
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