[postgis-tickets] [PostGIS] #5337: Row estimate for gist geometry index is more than 500 times smaller than actual count

[PostGIS]

#5337: Row estimate for gist geometry index is more than 500 times smaller than
actual count
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 Reporter:  Björn Harrtell  |      Owner:  pramsey
     Type:  defect          |     Status:  new
 Priority:  medium          |  Milestone:  PostGIS 3.4.0
Component:  postgis         |    Version:  3.2.x
 Keywords:                  |
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 I have a table that contains ~30 million mixed geometries of points,
 linestrings and polygons, mostly small but some few exceptions that are
 large. Data is not uniformly distributed.

 Counting rows within a small bbox (~5% of full extent) where real density
 is high results in 1.552.761 rows. Row estimate when looking at the
 explained plan is 2.819.

 The table is recently analyzed and I've attempted to adjust with set
 statistics on the geometry column to 1000 instead of default 100 hoping
 that could improve the estimate but it has little to no effect.

 Data is open at https://datafordeler.dk/dataoversigt/geodanmark-vektor
 /geodanmark-vektor-brugerdefineret-filudtraek/ but unfortunately it is in
 Danish only (I think?) and requires a cumbersome process to register and
 download. I might be able to provide a table copy if anyone is interested
 to look into this issue.

 postgis_full_version:
 POSTGIS="3.2.3 0" [EXTENSION] PGSQL="130" GEOS="3.9.2-CAPI-1.14.3"
 PROJ="9.0.1" LIBXML="2.9.4" LIBJSON="0.12.1" LIBPROTOBUF="1.2.1"
 WAGYU="0.5.0 (Internal)" (core procs from "3.1.1 aaf4c79" need upgrade)
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Ticket URL: <https://trac.osgeo.org/postgis/ticket/5337>
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