geowolf wrote
> On Wed, Mar 18, 2015 at 5:38 PM, Roel De Nijs <

> roel.denijs@

> >
> wrote:
> 
> Primary and secondary filter... the first one uses the spatial index, the
> second does the in memory filtering.
> Or has SQL Server learned to use the spatial index when just seeing
> STIntersects?
> 
> Even if it does, we'd might have to keep the current syntax for backwards
> compatibility with older versions
> 
> That said, SQLServer optimizer is really poor and expects some complicated
> setup in order to better optimize the queries (basically, writing the
> query
> in more than one bit, setting variables first in a few statements, then
> using them in the query) which is difficult to support with our current
> shared codebase for all databases... it's not impossible though, we are
> basically waiting for people to sponsor this work, as it's not small
> (won't
> fit in anybody's spare time).

We use a few custom-written queries which use only an STIntersects in the
where-clause and the spatial index is mentioned in the execution plan of
this query. So I think SQL Server has learned to use the spatial index :)
According to this blog post [1] it's very important to upgrade (if possible)
to SQL Server 2008 SP1 if you want to ensure the spatial index is being
used. (We use SQL Server 2008 R2)

I did a very simple test using one of our queries with different
combinations of Filter and/or STIntersects in the where-clause: 
a) only Filter: 76159 records in 9032ms
b) only STIntersects: 67490 records in 11472ms
c) Filter and STIntersects: 67490 records in 21472ms
I executed every query using the SQL Server Management Studio and before
each query I removed the query plans.

I tried the 3rd point from the blog post [1] as well, but no significant
changes in query execution time, nor in query execution plans.

[1]
http://www.sqlskills.com/blogs/bobb/how-to-ensure-your-spatial-index-is-being-used/

Kind regards,
Roel De Nijs
Senior Java Developer



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