Hi We have a rather strange performance issue with the Pointcloud extension [*]. The issue/bug may be in the extension, but we don't know for sure at this point. I'm writing to the list to hopefully get some guidance on how to further debug this. [*] <https://github.com/pgpointcloud/pointcloud> A query takes around 250 ms when executed first on a database connection. But it takes like 3 s when executed after a first very simple Pointcloud query. Below is a test-case with psql. Case #1 (works normally): psql (9.6.3) Type "help" for help. lopocs=# \timing Timing is on. lopocs=# select points from public.sthelens where pc_intersects(points, st_geomfromtext('polygon ((-2357334.41980829 -3742654.00016992, -2356120.91980829 -3742654.00016992, -2356120.91980829 -3741278.00016992, -2357334.41980829 -3741278.00016992, -2357334.41980829 -3742654.00016992))', 4978)); Time: 236.423 ms Case #2 (works abnormally): psql (9.6.3) Type "help" for help. lopocs=# \timing Timing is on. lopocs=# select pc_typmod_pcid(1); pc_typmod_pcid ---------------- 1 (1 row) Time: 4.917 ms lopocs=# select points from public.sthelens where pc_intersects(points, st_geomfromtext('polygon ((-2357334.41980829 -3742654.00016992, -2356120.91980829 -3742654.00016992, -2356120.91980829 -3741278.00016992, -2357334.41980829 -3741278.00016992, -2357334.41980829 -3742654.00016992))', 4978)); Time: 2987.491 ms The query takes 236 ms in case #1, and 2987 ms in case #2! Huge difference. Anyone has any idea where this performance drop may come from? The problem may be in the Pointcloud in the extension, but I have no idea where the bug may be. Any idea? Any suggestion on how to debug this? This has been driving us crazy for some time now. Thanks. -- Éric Lemoine Oslandia
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