Opened 5 years ago

Closed 5 years ago

Last modified 4 years ago

#2839 closed enhancement (fixed)

Improve raster selectivity estimator

Reported by: strk Owned by: pramsey
Priority: medium Milestone: PostGIS 2.2.0
Component: postgis Version: trunk
Keywords: raster, history Cc:

Description

As discussed in #1828 the selectivity estimator does noo support functional comparison, but for the raster case functional is the only possible index, and the histogram is already based on that exact same function.

This ticket is to find out if it's possible to check if the function used in the query is the same used to build the index. When that's the case, the estimator should behave exactly as if the query was not functional.

Change History (5)

comment:1 Changed 5 years ago by strk

Keywords: raster added

comment:2 Changed 5 years ago by strk

I've moved first steps toward support for functional index estimation: https://github.com/strk/postgis/tree/svn-trunk-raster-estimator Just in case you want to join :) [ not sure I'll ever continue it ]

comment:3 Changed 5 years ago by strk

Keywords: history added
Milestone: PostGIS 2.2.0
Resolution: fixed
Status: newclosed

Continued and completed ! r12814 in trunk

As a bonus track, we now support selectivity estimation on every expressional index whose expression returns a geometry.

comment:4 Changed 5 years ago by robe

refer to #2851

I think debbie I can work around by recompiling her postgres with xml support. Can we be sure most people testing will have their dev postgres compiled with xml support? I need to do the same for winnie (9.2 and below since I test those thru mingw).

the winnie regress not sure what causes that might be an issue.

comment:5 Changed 4 years ago by strk

See #2895 for a "can warm" consequence of this

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