| From: | Alexander Korotkov <a(dot)korotkov(at)postgrespro(dot)ru> |
|---|---|
| To: | Nikita Glukhov <n(dot)gluhov(at)postgrespro(dot)ru> |
| Cc: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Julien Rouhaud <rjuju123(at)gmail(dot)com>, Thomas Munro <thomas(dot)munro(at)gmail(dot)com>, Marc Cousin <cousinmarc(at)gmail(dot)com>, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com> |
| Subject: | Re: Avoid full GIN index scan when possible |
| Date: | 2019-12-26 01:59:48 |
| Message-ID: | CAPpHfdvT_t6ShG2pvptEWceDxEnyNRsm2MxmCWWvxBzQ-pbMuw@mail.gmail.com |
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| Lists: | pgsql-hackers |
On Wed, Dec 25, 2019 at 8:25 AM Alexander Korotkov <
a(dot)korotkov(at)postgrespro(dot)ru> wrote:
> Patch requires further polishing including comments, minor refactoring
> etc. I'm going to continue work on this.
>
I also run the same performance comparison as Nikita [1] on my laptop.
The results are shown below. PostgreSQL was built with -O2 and
asserts enabled.
| Query time, ms |
WHERE condition | master | patch |
---------------------------------------+--------+-------+
a @> '{}' | 117 | 116 |
a @> '{}' and b @> '{}' | 150 | 146 |
a @> '{}' and b @> '{}' and c @> '{}' | 168 | 167 |
a @> '{}' and a @@ '1' | 126 | 0.6 |
a @> '{}' and a @@ '-1' | 128 | 3.2 |
a @@ '!-1' and a @@ '1' | 127 | 0.7 |
a @@ '!1' and a @@ '-1' | 122 | 4.4 |
Performance effect looks similar to patch #4 by Nikita. I've tried to
add patch #4 to comparison, but I've catch assertion failure.
TRAP: FailedAssertion("key->includeNonMatching", File: "ginget.c", Line:
1340)
I'm going to continue polishing my version of patch.
Links
1.
https://www.postgresql.org/message-id/f2889144-db1d-e3b2-db97-cfc8794cda43%40postgrespro.ru
------
Alexander Korotkov
Postgres Professional: http://www.postgrespro.com
The Russian Postgres Company
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