[postgis-users] pg7.4.1 performance problem

[David Blasby]

Tyler Mitchell wrote:

> 
>  > Did you compile postgis with "USE_STATS=1"? Have you updated your
>  > stats tables
>  > recently by calling the correct function? It should be in the docs 
> somewhere,
>  > or if not, then it's at least in Dave's head.
> 
> DAVE - can you refresh our memories - what's the function.  What will 
> this stats option do for me?

its:

select update_geometry_stats();

Make sure your column is in the geometry_columns table.

When you "select * from geometry_columns;" you should see a big 
histogram2d in there.

Also, when you do an "EXPLAIN ANAYLSE ..." you should see the predicted 
# of rows to be 'close to' the actual number of rows.

dave