Hello! I brought up this question before but basically I am still unsure of how multithreading fits into Geotools when it comes to raster processing (making it a JAI question, I guess). JAI being a lazy "pull"-based API I would expect the terminal operations (such as encoding a raster into a format for export, such as GeoTIFF) having some sort of multiprocessing ability, but that does not seem to be the case?
Last time I posed this question I was pointed to this code: https://github.com/geosolutions-it/soil_sealing/blob/96a8c86e9ac891a273e7bc61b910416a0dbe1582/src/extension/wps-soil-sealing/wps-changematrix/src/main/java/org/geoserver/wps/gs/soilsealing/ChangeMatrixProcess.java#L669 Similar to the above I currently I do this: private void triggerActualCalculation(RenderedImage renderedImage) { final int numTileY = renderedImage.getNumYTiles(), numTileX = renderedImage.getNumXTiles(), minTileX = renderedImage.getMinTileX(), minTileY = renderedImage.getMinTileY(); final List<Point> tiles = new ArrayList<Point>(numTileX * numTileY); for (int i = minTileX; i < minTileX + numTileX; i++) { for (int j = minTileY; j < minTileY + numTileY; j++) { tiles.add(new Point(i, j)); } } tiles.stream() .parallel() .forEach(tileIndex -> renderedImage.getTile(tileIndex.x, tileIndex.y)); } This seems to cause the rendering chain to be performed in parallel, but now it looks like I need to make sure that all computed tiles fit into the tile cache, or else I guess tiles will be thrown out and recomputed again when invoking the GeoTiffWriter to actually serialize the raster. So it seems like I need to choose between doing things in parallel or having enough memory for all the tiles to fit into the tile cache. While the resulting image is just a single band (as opposed to the 100 something bands used as inputs), it seems like there must a better way to do this, having tiles computed in parallel but all of them not necessarily fitting into the tile cache (the raster grid can potentially be very large and we would like to be able to deploy this system on machines without huge amounts of RAM). As I understand it Geotools was designed to cope with these constraints, but how is it to be done? Regards, Tobias Gerdin Havs- och vattenmyndigheten behandlar dina personuppgifter i enlighet med dataskyddsf?rordningen och myndighetens dataskyddspolicy, l?s mer p? www.havochvatten.se/sa-behandlar-hav-dina-personuppgifter<https://www.havochvatten.se/sa-behandlar-hav-dina-personuppgifter> SwAM processes your personal data in accordance with the General Data Protection Regulation (GDPR) and our Data Protection Policy, see www.havochvatten.se/sa-behandlar-hav-dina-personuppgifter<https://www.havochvatten.se/sa-behandlar-hav-dina-personuppgifter>
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