[postgis-users] Trunk 2.0.0 seem slow on Linux 64 bit

[Andrea Peri]

Hi,

I have a query which on a notebook with Window7 - 64 bit ,
with postgres 8.4.4 32bit and Postgis 1.5.1 32 bit
work in about 10 minutes.

When I try the same query on a machine quite big then the notebook.
And with
Linux RedHat 64 bit ,
but using Postgres 8.4.4 compile from source (64bit)
and Geos from trunk, and Postgis from trunk all compiled to 64 bit.

The same query sql run for a time really huge.
(some hours ..)

The query is this
INSERT INTO PUBLIC._TEST_CAMPIONAMENTO (id,idrtt,geom) (
        select
            a.oid::integer,
            a.id,
            ST_Force_2D(ST_Multi(a.geom))
        from
            public.table1 as a,
            public._sample_extent as b
        where
            ST_Intersects(a.geom,b.geom)=true
)
;

The only think I can do is passing from the trunk version 2.0.0 to the 1.5.1
version,
but this mean to reload the table "table1". Because this table is quite huge
(more the 9.500.000 records with many vertex on each records)
and reload it require a bit of time.
And I have some doubt that the 2.0.0 trunk was more slow than 1.5.1.

Before try this I have a question to ask:

the table" _sample_extent " is one only record with a multipolygon having
about 20 part disjoint each other, but not near each other.
I don't know if the GIST index use only one unique extent of all the
MultiPolygon or use more single extents one for each parts ?

And could be somethink is changed from 1.5.1 to 2.0.0 in the strategy of GIS
index ?

Many thx,

Andrea

-- 
-----------------
Andrea Peri
. . . . . . . . .
qwerty àèìòù
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