pg.ddx.io  pgsql-hackers@postgresql.org mailing list archive  

help / color / mirror / Atom feed
From: Joel Jacobson <joel@compiler.org>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: pgsql-hackers@lists.postgresql.org
Subject: Re: Some regular-expression performance hacking
Date: Thu, 18 Feb 2021 21:44:07 +0100
Message-ID: <ef5463ba-3e3c-45ec-bf02-27f91c6e09ab@www.fastmail.com> (raw)
In-Reply-To: <d8899c66-5492-43e9-8eff-a07d1d593ad0@www.fastmail.com>
References: <1340281.1613018383@sss.pgh.pa.us>
	<85140bfb-516c-449b-8a03-7930abb42b88@www.fastmail.com>
	<1813969.1613250697@sss.pgh.pa.us>
	<913516b8-c3d7-4dea-bf60-d735cf4673f1@www.fastmail.com>
	<2155152.1613358697@sss.pgh.pa.us>
	<99f6cbe0-6e58-4e41-add0-977271a5cf84@www.fastmail.com>
	<2752386.1613595636@sss.pgh.pa.us>
	<5deabab3-a335-4b57-a046-8a9ad8f2f142@www.fastmail.com>
	<12e6381c-adc1-4711-a619-864fb8df969c@www.fastmail.com>
	<2840118.1613671847@sss.pgh.pa.us>
	<d8899c66-5492-43e9-8eff-a07d1d593ad0@www.fastmail.com>

On Thu, Feb 18, 2021, at 20:58, Joel Jacobson wrote:
>Like you said earlier, perhaps the regex engine has been optimized enough for this time.
>If not, you want to investigate an additional idea,

In the above sentence, I meant "you _may_ want to".
I'm not at all sure these idea are applicable in the PostgreSQL regex engine,
so feel free to silently ignore these if you feel there is a risk for time waste.

>that I think can be seen as a generalization of the optimization trick for (.*),
>if I've understood how it works correctly.

Actually not sure if it can be seen as a generalization,
I just came to think of my ideas since they also improve
the case when you have lots of (.*) or bracket expressions of large ranges.

/Joel

view thread (38+ messages)  latest in thread

Message-ID: <ef5463ba-3e3c-45ec-bf02-27f91c6e09ab@www.fastmail.com>
Permalink:  ../ef5463ba-3e3c-45ec-bf02-27f91c6e09ab@www.fastmail.com/
Also on:    postgresql.org/message-id/ef5463ba-3e3c-45ec-bf02-27f91c6e09ab@www.fastmail.com

 · 

reply
Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: pgsql-hackers@postgresql.org
  Cc: joel@compiler.org, tgl@sss.pgh.pa.us, pgsql-hackers@lists.postgresql.org
  Subject: Re: Some regular-expression performance hacking
  In-Reply-To: <ef5463ba-3e3c-45ec-bf02-27f91c6e09ab@www.fastmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox