[postgis-users] Downgrade from PostGIS2.0 to PostGIS1.5

[oisink]

Hi Lelo

Many thanks for taking the time to reply to my message. 

I'll explain what I am doing and what I think is happening below, but please
note I'm a bit of a noob....so forgive any misunderstandings on my part.

First, I'm not sure if it makes any difference but I'm pretty sure I am not
using any datatype in PG20 that is not also in PG14. In terms of spatial
datatypes I am only using a geometry type, with CONSTRAINT
enforce_srid_geometry CHECK (st_srid(geom) = 27700 and a GIST index.

Assuming I still cannot simply downgrade, my situation is as follows:

I have a large spatial database (200GB, 2000+ relations) in PostgreSQL 8.4 /
PostGIS 1.4 (let's call this PG14). I am migrating the database to a new
server and upgrading to PostgreSQL 9.1.8 / PostGIS 2.0.(let's call this
PG20). So currently I have two databases containing similar data but of
different versions and on different servers.

I am finding that using PGAdmin III (both locally and remote) PG14 and PG20
are giving very similar response times for similar queries. However,
connecting with my desktop GIS package (Manifold), PG14 responds much more
quickly - there seems to be about 90 seconds delay in connecting to PG20. I
attach the log outputs from Server Status, which are generated (1) on
connecting to PG from Manifold and (2) on linking to a specific relation.

One possible issue of significance is that in PG14, only those relations in
"geometry_columns" are exposed to Manifold. Since in PG14 entries to PG14
were manual, only 50 or so relations were exposed. However in PG20,
"geometry_columns" is a VIEW generated from system tables and so all 2000+
relations are exposed to Manifold - could this be part or all of the issue?
I did try editing the SQL for "geometry_columns" in an attempt to reduce the
nmumber of relations exposed, but this made no difference - so my version of
events is clearly not the full picture.

Thanks

pg_logs.TXT <http://postgis.17.x6.nabble.com/file/n5003035/pg_logs.TXT>  



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