Re: Soon-to-be-broken regression test case
От | Alvaro Herrera |
---|---|
Тема | Re: Soon-to-be-broken regression test case |
Дата | |
Msg-id | 20181011165251.k7ggwmvmlfjv33gr@alvherre.pgsql обсуждение исходный текст |
Ответ на | Re: Soon-to-be-broken regression test case (Tom Lane <tgl@sss.pgh.pa.us>) |
Ответы |
Re: Soon-to-be-broken regression test case
Re: Soon-to-be-broken regression test case |
Список | 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
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