[postgis-users] [postgis-devel] Oddity in _ST_Expand(geography) ?

Pavan Deolasee pavan.deolasee at gmail.com
Mon Jul 9 22:18:32 PDT 2018

On Thu, Jul 5, 2018 at 6:47 PM, Pavan Deolasee <pavan.deolasee at gmail.com>

> While I look at the XL side more carefully and see if we can revert back
> to PG's behaviour, I still believe this is a problem that we should fix on
> the PostGIS side (too). AFAIK in PostgreSQL we assume that out/in functions
> should safely convert a value to a string and back to its in-memory
> representation. So keeping that guarantee for the "geography" data type
> seems like the right thing to do.
Any feedback here? I am willing to write a patch if the community guides me
in the right direction. My knowledge of PostGIS is quite limited and I am
not sure if changing the text representation of the geography type is

BTW I tried to work around this problem by patching ST_DWithin(geography,
float) so that the overlap is checked inside the C function. While that
fixes the problem at hand, it regresses the query planning because planner
can no longer see those additional quals and switches from an index scan to
a seq scan. So I'd to abandon that approach.

Any help is highly welcome.


 Pavan Deolasee                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services
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