Opened 4 years ago

Last modified 3 years ago

#3555 new enhancement

Parallelization of PostGIS raster ST_Union aggregate

Reported by: robe Owned by: Bborie Park
Priority: medium Milestone: PostGIS Fund Me
Component: raster Version: master
Keywords: Cc:


I experimented with this and sadly I think this is a no go for PostgreSQL 9.6, though I'm keeping ourt hope for PostgreSQL 9.7.

The reason I think it's a no go (unless we revise postgis raster ST_Union to use similar approach to ST_MemUnion (which might result in more loss than gain) is because I don't think the PostgresQL parallel aggregate infrastructure can support aggregates that use state transitions.

Reason I thin that is that function like string_agg, array_agg don't support parallelization in 9.6

I'm guessing its because they use that internal state transition stuff that we employ with our raster aggregates.

I'll try to still experiment with a couple of approaches before I give up on 9.6 parallelization for raster.

The ST_MapAlgebra functions look like good candidates for parallelization, so I'll add that aas a separate ticket, as I think that one would be easier to swing.

Change History (1)

comment:1 Changed 3 years ago by robe

Milestone: PostGIS FuturePostGIS Fund Me

Milestone renamed

Note: See TracTickets for help on using tickets.