[postgis-users] Insert performance issues

[Nicolas RIBOT]

Hi,

We have a question concerning insert/update/delete queries on a postgis
DB.

We use postgis to store a polygon layer (120 000 polygons, some of them
with more than 160 000 vertices).

We use ArcGIS to modify these polygons.
Once the edition session is done, we generate an SQL script to
update/delete/insert polygons into postgis.
Some times, it takes more than 20 minutes to run the script (1 Mb of SQL
queries)
We wondered why performance is so bad.

The configuration:
Postgresql 7.2, postgis 0.7.2
Linux Mandrake
Pentium III 1 Ghz
256 Mb ram
This computer is dedicated to this database, on a 100 Mb LAN

The geographic table is indexed for all the fields involved in the
queries.
the geographic column is indexed with a GIST index.
A vacuum is ran once a week

Should we run a vacuum more often (full, analyse?) ?
Does it take a long time to maintain indices on the table for each
insert or delete. ?
Is it necessary to index all fields involved in the query ?

Thanx for any hint.

Nicolas Ribot