From: | Alvaro Herrera <alvherre(at)2ndquadrant(dot)com> |
---|---|
To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
Cc: | Robert Haas <robertmhaas(at)gmail(dot)com>, Jeevan Chalke <jeevan(dot)chalke(at)enterprisedb(dot)com>, pgsql-hackers(at)lists(dot)postgresql(dot)org, David Rowley <david(dot)rowley(at)2ndquadrant(dot)com> |
Subject: | Re: Soon-to-be-broken regression test case |
Date: | 2018-10-11 16:52:51 |
Message-ID: | 20181011165251.k7ggwmvmlfjv33gr@alvherre.pgsql |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 2018-Oct-11, Tom Lane wrote:
> Hm, I'm not seeing any regression test result changes there. However,
> if you're just executing queries and not EXPLAIN'ing them, it's possible
> something unwanted is happening under the hood.
Hmm, no, the explains are there. Here's one example -- maybe your new
planner smarts do not change these plans for some reason (I note that
you mentioned EXISTS in your OP, which this one does not use; I further
note that we don't use EXISTS anywhere in partition_prune.sql, which
probably amounts to uncovered cases):
prepare ab_q2 (int, int) as
select a from ab where a between $1 and $2 and b < (select 3);
explain (analyze, costs off, summary off, timing off) execute ab_q2 (2, 2);
QUERY PLAN
--------------------------------------------------------
Append (actual rows=0 loops=1)
InitPlan 1 (returns $0)
-> Result (actual rows=1 loops=1)
Subplans Removed: 6
-> Seq Scan on ab_a2_b1 (actual rows=0 loops=1)
Filter: ((a >= $1) AND (a <= $2) AND (b < $0))
-> Seq Scan on ab_a2_b2 (actual rows=0 loops=1)
Filter: ((a >= $1) AND (a <= $2) AND (b < $0))
-> Seq Scan on ab_a2_b3 (never executed)
Filter: ((a >= $1) AND (a <= $2) AND (b < $0))
(10 rows)
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
From | Date | Subject | |
---|---|---|---|
Next Message | Konstantin Knizhnik | 2018-10-11 17:04:11 | Re: out-of-order XID insertion in KnownAssignedXids |
Previous Message | Tom Lane | 2018-10-11 16:45:24 | Re: Soon-to-be-broken regression test case |