[postgis-devel] Caching Double-based Boxes

[Sandro Santilli]

On Thu, Nov 24, 2011 at 09:48:40PM -0500, Paragon Corporation wrote:

> 1) If your index is still float while your cached box is double, you still
> have the unpleasant issue
> of your indexed search possibly giving a different answer from the
> non-indexed one (and in fact more so).  Or am I mistaken?

When I left, I remember we had a RECHECK issued in place.
Is the RECHECK still there ? If it is, the presence of index
shouldn't change the view on reality.

> 2) This still requires a dump / reload for those using PostGIS 2.0 in a
> pseudo production environment
> or am I mistaken? 

Nobody should be using 2.0 in a production environment if not ready
to dump/reload.

BTW: was the storage format versioning thing put in place ?
     a dump/reload would also help ensuring that, to avoid
     _next_ dump/reload ...

> 3) Disk space.  So how much exactly are we talking about here in a good
> case?
> 10% above what the cached box used to take up?

It's 4 more bytes per dimension for each Geometry value
(float is 4 bytes, double is 8)

Best case (points): 0 bytes
Average case (lineal, areal, 2d): 8 bytes
Worst case (lineal, areal, 4d): 16 bytes


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