Re: partition queries hitting all partitions even though check key is specified

On Wednesday 02 September 2009 09:02:27 Scott Marlowe wrote:
> On Wed, Sep 2, 2009 at 8:52 AM, Kevin Kempter<kevink(at)consistentstate(dot)com>
wrote:
> > Hi all;
> >
> > I cant figure out why we're scanning all of our partitions.
> >
> > We setup our tables like this:
> >
> >
> > Base Table:
> >
> > CREATE TABLE url_hits (
> > id integer NOT NULL,
> > content_type_id integer,
> > file_extension_id integer,
> > "time" integer,
> > bytes integer NOT NULL,
> > path_id integer,
> > protocol public.protocol_enum
> > );
> >
> > Partitions:
> > create table url_hits_2011_12 (
> > check (
> > "time" >= extract ('epoch' from timestamp '2011-12-01
> > 00:00:00')::int4
> > and "time" <= extract ('epoch' from timestamp '2011-12-31
> > 23:59:59')::int4
> > )
> > ) INHERITS (url_hits);
> >
> >
> > CREATE RULE url_hits_2011_12_insert as
> > ON INSERT TO url_hits
> > where
> > ( "time" >= extract ('epoch' from timestamp '2011-12-01
> > 00:00:00')::int4 and "time" <= extract ('epoch' from timestamp
> > '2011-12-31
> > 23:59:59')::int4 )
> > DO INSTEAD
> > INSERT INTO url_hits_2011_12 VALUES (NEW.*) ;
> >
> > ...
> >
> > create table url_hits_2009_08 (
> > check (
> > "time" >= extract ('epoch' from timestamp '2009-08-01
> > 00:00:00')::int4
> > and "time" <= extract ('epoch' from timestamp '2009-08-31
> > 23:59:59')::int4
> > )
> > ) INHERITS (url_hits);
> >
> >
> > CREATE RULE url_hits_2009_08_insert as
> > ON INSERT TO url_hits
> > where
> > ( "time" >= extract ('epoch' from timestamp '2009-08-01
> > 00:00:00')::int4 and "time" <= extract ('epoch' from timestamp
> > '2009-08-31
> > 23:59:59')::int4 )
> > DO INSTEAD
> > INSERT INTO url_hits_2009_08 VALUES (NEW.*) ;
> >
> > ...
> >
> > the explain plan shows most any query scans/hits all partitions even if
> > we specify the partition key:
> >
> > explain select * from pwreport.url_hits where "time" >
> > date_part('epoch'::text, '2009-08-12'::timestamp without time
> > zone)::integer;
>
> Have you tried using extract here instead of date_part ?

Yes, same results:

explain select * from pwreport.url_hits where "time" > extract('epoch' from
timestamp '2009-08-12 00:00:00')::int4;
QUERY PLAN
------------------------------------------------------------------------------------------------------
Result (cost=0.00..23785180.16 rows=817269615 width=432)
-> Append (cost=0.00..23785180.16 rows=817269615 width=432)
-> Seq Scan on url_hits (cost=0.00..12.12 rows=57 width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_12 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_11 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_10 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_09 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_08 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_07 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_06 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_05 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_04 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_03 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_02 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2011_01 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_12 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_11 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_10 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_09 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_08 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_07 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_06 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_05 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_04 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_03 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_02 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2010_01 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2009_12 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2009_11 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2009_10 url_hits (cost=0.00..12.12 rows=57
width=432)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2009_09 url_hits (cost=0.00..1856896.86
rows=76384671 width=128)
Filter: ("time" > 1250035200)
-> Seq Scan on url_hits_2009_08 url_hits (cost=0.00..21927943.80
rows=740883348 width=131)
Filter: ("time" > 1250035200)
(62 rows)