Horton

Re: Allowing extensions to supply operator-/function-specific info

Paul Ramsey <pramsey@cleverelephant.ca>

View thread
From: Paul Ramsey <pramsey@cleverelephant.ca>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2019-03-04T19:20:45Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Allow extensions to generate lossy index conditions.

  2. Build out the planner support function infrastructure.

  3. Create the infrastructure for planner support functions.

  4. Disable transforms that replaced AT TIME ZONE with RelabelType.

So I am getting much closer to a working implementation in PostGIS,
but have just run into an issue which I am assuming is my
misunderstanding something...

https://github.com/pramsey/postgis/blob/92268c94f3aa1fc63a2941f2b451be15b28662cf/postgis/gserialized_supportfn.c#L287

I had what seemed to be working code except for a couple rare cases,
but when I fixed those cases it turned out that I had a major problem:
building a <var> OP <const> expression works fine, but building a
<const> OP <var> expression returns me an error.

create table f as select st_makepoint(200*random() - 100, 200*random()
- 100) as g from generate_series(0, 100000);
create index f_g_x on f using gist (g);
explain select * from baz where st_coveredby('POINT(5 0)', geom);
explain select * from f where st_coveredby(g, 'POINT(5 0)');

                                    QUERY PLAN
-----------------------------------------------------------------------------------
 Bitmap Heap Scan on f  (cost=13.36..314.58 rows=33334 width=32)
   Filter: st_coveredby(g,
'010100000000000000000014400000000000000000'::geometry)
   ->  Bitmap Index Scan on f_g_x  (cost=0.00..5.03 rows=100 width=0)
         Index Cond: (g @
'010100000000000000000014400000000000000000'::geometry)

postgis=# explain select * from f where st_coveredby('POINT(5 0)', g);

ERROR:  index key does not match expected index column

Any thoughts?

P