Remove Full Outer Join From S3 Backend

[jamesmcclain]

• Add Layer Overwriting Support #2357

Connects #2327

Benchmark

Code

import geotrellis.spark._
import geotrellis.spark.io._
import geotrellis.spark.io.s3._
import geotrellis.raster._

implicit val _sc = sc

val as = S3AttributeStore("geotrellis-test", "jmcclain/ned")
val id = LayerId("landsat", 13)
val reader = S3LayerReader(as)
val layer = reader.read[SpatialKey, Tile, TileLayerMetadata[SpatialKey]](id)
val strip = ContextRDD(layer.repartition(256).filter({ case (SpatialKey(x, y), _) => 2*x == y }), layer.metadata)
val updater = new S3LayerUpdater(as, reader)

println(System.currentTimeMillis) ; updater.update(id, strip, {(v1: Tile, v2:Tile) => v1 }) ; println(System.currentTimeMillis)

Results

	mean first run (millis)	mean subsequent runs (millis)
current	83214	34538.5
PR	42050.5	3606.75