G'day Vincent,
This didn't work as anticipated - in fact it appears to have truncated
the table!
On 08/01/2009, at 5:01 AM, postgis-users-
[email protected] wrote:
Another and more <classic> solution (despite slower on big tables) to
keep spatially close rows together on disk is to use postgresql
CLUSTER
statement.
http://www.postgresql.org/docs/8.3/static/sql-cluster.html
CLUSTER reorders data on disk using a specified index, therefore
increasing access speed when reading rows in the index order.
Example :
CREATE INDEX idx_mytable_the_geom ON mytable USING GIST(the_geom);
CLUSTER mytable USING idx_mytable_the_geom;
CLUSTER works on a normal index :
# select count(*) from gis_roads;
count
-------
89618
(1 row)
# CLUSTER gis_roads USING gis_roads_gid_key;
CLUSTER
# select count(*) from gis_roads;
count
-------
89618
(1 row)
all good!
But when I try on the gist index
# CLUSTER gis_roads USING gis_roads_gist;
CLUSTER
# select count(*) from gis_roads;
count
-------
0
(1 row)
whoops!
Is this something I missed? Is this a PostgreSQL bug... surely the
cluster command shouldn't be allowed to destroy a whole table.
cheers
Ben
--
Ben Madin
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Broome WA 6725
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know...
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