From: Tom Lane <tgl@sss.pgh.pa.us>
To: "ldh@laurent-hasson.com" <ldh@laurent-hasson.com>
cc: Marc Mamin <M.Mamin@intershop.de>,
        "pgsql-performance@postgresql.org" <pgsql-performance@postgresql.org>
Subject: Re: Inlining of functions (doing LIKE on an array)
In-reply-to: 
 <35BE9BD1DD4DD444B0EDE3721E2AEA860115DECB@P3PWEX4MB001.ex4.secureserver.net>
References: 
 <35BE9BD1DD4DD444B0EDE3721E2AEA860115CB08@P3PWEX4MB001.ex4.secureserver.net>
 <B6F6FD62F2624C4C9916AC0175D56D88421F197B@jenmbs01.ad.intershop.net>
 <35BE9BD1DD4DD444B0EDE3721E2AEA860115D550@P3PWEX4MB001.ex4.secureserver.net>
 <29682.1478882784@sss.pgh.pa.us>
 <35BE9BD1DD4DD444B0EDE3721E2AEA860115DECB@P3PWEX4MB001.ex4.secureserver.net>
Comments: In-reply-to "ldh@laurent-hasson.com" <ldh@laurent-hasson.com>
	message dated "Sat, 12 Nov 2016 00:41:16 +0000"
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <2794.1478980772.1@sss.pgh.pa.us>
Content-Transfer-Encoding: quoted-printable
Date: Sat, 12 Nov 2016 14:59:32 -0500
Message-ID: <2795.1478980772@sss.pgh.pa.us>
Precedence: bulk
Sender: pgsql-performance-owner@postgresql.org

"ldh@laurent-hasson.com" <ldh@laurent-hasson.com> writes:
> I wish there were a way to force inlining, or some other mechanism as the=
 performance difference is large here. I'll be using the inlining approach =
when possible, but the SQL Function approach is simpler and will likely be =
more suitable for some developers.

I'm not sure that there's any fundamental reason why we don't inline SQL
functions containing sub-selects.  It may just be not having wanted to put
any effort into the case way-back-when.  Inlining happens too late to
allow a resulting WHERE EXISTS to get mutated into a semijoin, but in this
example that couldn't happen anyway, so it's not much of an objection.

			regards, tom lane


--=20
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance