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: | Ashutosh Bapat <ashutosh(dot)bapat(at)enterprisedb(dot)com>, Robert Haas <robertmhaas(at)gmail(dot)com>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Amit Langote <amitlangote09(at)gmail(dot)com>, Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org>, "pgsql-hackers(at)postgresql(dot)org" <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: [HACKERS] path toward faster partition pruning |
Date: | 2018-04-11 08:59:48 |
Message-ID: | CAKJS1f8RWDvYB8dmh7E4CfkW4Sf+wFD81QKnACXc2JzZKH+nVw@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
On 11 April 2018 at 18:04, Amit Langote <Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> Updated patch attached.
Thanks for the updated patch.
The only thing I'm not sure about is the chances you've made to the
COALESCE function.
+CREATE OR REPLACE FUNCTION pp_hashint4_noop(int4, int8) RETURNS int8 AS
+$$SELECT coalesce($1, $2)::int8$$ LANGUAGE sql IMMUTABLE;
+CREATE OPERATOR CLASS pp_test_int4_ops FOR TYPE int4 USING HASH AS
+OPERATOR 1 = , FUNCTION 2 pp_hashint4_noop(int4, int8);
+CREATE OR REPLACE FUNCTION pp_hashtext_length(text, int8) RETURNS int8 AS
+$$SELECT length(coalesce($1, ''))::int8$$ LANGUAGE sql IMMUTABLE;
Why does one default to the seed and the other to an empty string?
Shouldn't they both do the same thing? If you were to copy the
hash_part.sql you'd just coalesce($1, 0) and coalesce($1, ''), any
special reason not to do that?
Also just wondering if it's worth adding some verification that we've
actually eliminated the correct partitions by backing the tests up
with a call to satisfies_hash_partition.
I've attached a delta patch that applies to your v2 which does this.
Do you think it's worth doing?
--
David Rowley http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
Attachment | Content-Type | Size |
---|---|---|
add_satisfies_hash_partition_verification.patch | application/octet-stream | 5.0 KB |
From | Date | Subject | |
---|---|---|---|
Next Message | Mark Rofail | 2018-04-11 09:16:39 | Re: [HACKERS] GSoC 2017: Foreign Key Arrays |
Previous Message | Christoph Berg | 2018-04-11 08:39:54 | Re: submake-errcodes |