[postgis-users] LWGEOM_gist_joinsel called with incorrect join type

[strk]

On Wed, Feb 03, 2010 at 03:04:39PM +0800, Ben Madin wrote:

> NOTICE:  LWGEOM_gist_joinsel called with incorrect join type
> 
> >From trial and error I find that just an (inner) JOIN doesn't give me the notice, but neither do I get a complete list of provinces.
> 
> Can I ignore the notice and be confident that I am getting the data I anticipate. Why is this a notice?

You can ignore the notice and be confident you'll get what you asked for.
That message comes from the estimator. The real meaning (true that the
message is confusing) is that the estimator for geometry selectivity
doesn't support outer joins but only inner ones. The effect is that the
estimator will return a default value instead.

The default value is 0.000005, which means that fraction of rows
which are in the table will be returned. Usually this in turns means
that the planner will use an index rather than a table scane.

After all, for outer joins, we might better return 1 instead as
the join itself doesn't really restrict the selection on itself.

What do you think Mark ?


--strk; 

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