From: | Robert Haas <robertmhaas(at)gmail(dot)com> |
---|---|
To: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | EXPLAIN WITH |
Date: | 2009-04-05 13:40:11 |
Message-ID: | 603c8f070904050640tcff2fadwd12dc39fedfac3c4@mail.gmail.com |
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Lists: | pgsql-hackers |
I'm a bit unsatisfied with this output because it doesn't tell me the
plan it used to construct the CTE being scanned.
rhaas=# explain with wumpus as (select * from foo where id < 200)
select * from foo f, wumpus c, wumpus u where f.creator_id = c.id and
f.last_updater_id = u.id;
QUERY PLAN
-----------------------------------------------------------------------------
Hash Join (cost=31.44..74.94 rows=1000 width=36)
Hash Cond: (f.creator_id = c.id)
InitPlan
-> Seq Scan on foo (cost=0.00..18.50 rows=199 width=12)
Filter: (id < 200)
-> Hash Join (cost=6.47..36.22 rows=1000 width=24)
Hash Cond: (f.last_updater_id = u.id)
-> Seq Scan on foo f (cost=0.00..16.00 rows=1000 width=12)
-> Hash (cost=3.98..3.98 rows=199 width=12)
-> CTE Scan on wumpus u (cost=0.00..3.98 rows=199 width=12)
-> Hash (cost=3.98..3.98 rows=199 width=12)
-> CTE Scan on wumpus c (cost=0.00..3.98 rows=199 width=12)
(12 rows)
I haven't looked at what would be required to fix this, but I think we
should fix it before releasing 8.4.
...Robert
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