[postgis-devel] [raster] Paths local to server

[Bborie Park]

On Thu, Feb 28, 2013 at 9:03 PM, Paragon Corporation <lr at pcorp.us> wrote:
> I definitely have use for ST_BandPath so we should keep it.
>
> Especially since ST_Tile for example creates out of db (and if you copy from
> one table to another) it is very conceivable you could have a mix of in
> database and out of database rasters in the SAME table.  This could be by
> accident or intentional.
>
> I haven't tried to but based on my understanding of our design, I can think
> of steps to do create this hybrid table creature.
>
> That said as Mat proposed, having ST_AsBinary be consistent between in db
> and out db becomes very important, because you don't want to have a
> third-party tool relying on ST_Asbinary have to worry about this
> implementation detail if we say its for abstracting away this.
>
> As I mentioned to Bborie, as long as our serialized (which backup uses)
> keeps paths (and not full), that is all we need.  In fact serialized
> definitely has to be different between the two.  I suspect some of the
> performance gains I am seeing with out of db in 2.1 is because out db (for
> operations that don't need to touch the underlying raster), is much faster
> than in db since less memcopy going on I presume.
>
>  My 2cents,
> Regina
> http://www.postgis.us
> http://postgis.net
>

Our serialized format will not change.  I tested pg_dump on a out-db
raster and the dump only contains the raster information stored in the
database.

Out-db is faster because there is significantly less data to
decompress and deserialize.

-bborie