From: | David Rowley <david(dot)rowley(at)2ndquadrant(dot)com> |
---|---|
To: | Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> |
Cc: | Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>, Rajkumar Raghuwanshi <rajkumar(dot)raghuwanshi(at)enterprisedb(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Dilip Kumar <dilipbalaut(at)gmail(dot)com>, Beena Emerson <memissemerson(at)gmail(dot)com>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: [HACKERS] path toward faster partition pruning |
Date: | 2017-12-21 12:04:48 |
Message-ID: | CAKJS1f9svmTtH5oh-7+zBs2Y_hoJH8=eR64jVcBWZ5cKOkoifQ@mail.gmail.com |
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Lists: | pgsql-hackers |
On 21 December 2017 at 23:38, Amit Langote
<Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> Attached updated set of patches.
Looks like the new not equals code does not properly take into account
a missing NULL partition.
create table ta (a int not null) partition by list (a);
create table ta1 partition of ta for values in(1,2);
create table ta2 partition of ta for values in(3,4);
explain select * from ta where a <> 1 and a <> 2;
ERROR: negative bitmapset member not allowed
-- Add null partition
create table ta_null partition of ta for values in(null);
explain select * from ta where a <> 1 and a <> 2; -- works now.
QUERY PLAN
-------------------------------------------------------------
Append (cost=0.00..48.25 rows=2525 width=4)
-> Seq Scan on ta2 (cost=0.00..48.25 rows=2525 width=4)
Filter: ((a <> 1) AND (a <> 2))
(3 rows)
This code appears to be at fault:
/*
* Also, exclude the "null-only" partition, because strict clauses in
* ne_clauses will not select any rows from it.
*/
if (count_partition_datums(relation, boundinfo->null_index) == 0)
excluded_parts = bms_add_member(excluded_parts,
boundinfo->null_index);
--
David Rowley http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
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