Do you use PostGIS BRIN?

[Paul Ramsey]

> I think adding new functions is not a breaking change - there's the risk
> people might not have updated the definitions, but in the worst case the
> those functions would not be called. It's the removal of functions that
> breaks things.

Yes, unfortunately there’s no way to “clean up” the BRIN code, the function stubs end up having to lie around forever and ever, it seems.

> Attached is a patch fixing the brin_geometry_inclusion_ops_2d opclass
> (at least I believe so). The 3d/4d opclasses would need a similar fix,
> derived from gidx_brin_inclusion_add_value.

Reading through the existing code and the default implementations in pgsql, I think that we need to keep geom2d_brin_inclusion_add_value around, since the “value” handed in by the API will be a geometry, and the default implementation will just copy that whole value into the BrinValues, while we want instead to have just the box2df copied in. The GIST API has a “compress” method to go from the column type to the key type, but it seems like we have to handle this at the point of consumption which is the add_value support function. Am I right in this, or is there some special machinery that would ensure that the "Datum newval” coming into the brin_inclusion_add_value() was a box2df even though the column type is geometry? 

The BRIN API has a lot of good stuff now, which would be good to add to simplify some of the other code (check for empty, check for contained, check for mergeable) I am not sure when in the history of BRIN it was added, do you have a quick feel for that?

> This doesn't make amvalidate 100% happy though, it still complains about
> missing functions, but I believe it just gets confused by the cross-type
> operators.

To what extent do you think we need those cross-type operators? box2df is a stub type, and it is not creatable in SQL, to my knowledge, what does having those op(geometry, box2df), op(box2df, box2df), etc, etc, operators buy us?

P

> 
> regards
> 
> -- 
> Tomas Vondra
> <postgis-brin-fix.patch>

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