To: David Schnur <dnschnur@gmail.com>
cc: pgsql-admin@postgresql.org
Subject: Re: How and when are encoding DLLs used on Windows? 
In-reply-to: 
 <CAANiQEmx3gy1B2vMiS6WaHHAEzKXn-kBHzaxe+9aL=d2=0JJJw@mail.gmail.com>
References: 
 <CAANiQEmx3gy1B2vMiS6WaHHAEzKXn-kBHzaxe+9aL=d2=0JJJw@mail.gmail.com>
Comments: In-reply-to David Schnur <dnschnur@gmail.com>
	message dated "Wed, 16 Nov 2011 11:04:59 -0500"
Date: Wed, 16 Nov 2011 18:57:57 -0500
Message-ID: <24309.1321487877@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>

David Schnur <dnschnur@gmail.com> writes:
> I bundle Postgres (8.3.15) with another product as a back-end database.  On
> Windows, the default build includes a bunch of what appear to be codec
> libraries, with names like, utf8_and_cyrillic.dll, ascii_and_mic.dll, etc.
>  But using Microsoft's dependency walker tool, I see no references to any
> of these in libpq.dll, psql, postgres or initdb.

> So I'm wondering what these are used for, what executable or library ends
> up loading them, and when/how exactly this happens.

They're used for character set encoding conversions, eg when
database_encoding = UTF8 and client_encoding = LATIN1 (or any other
non-identical combination).

> I'd like to know
> whether they're actually necessary, since we could save some space in our
> installer by omitting them.

AFAIR, the system will function without 'em ... until you try to set
client_encoding different from database_encoding.  Removing that
functionality doesn't seem like a good idea to me, but if you know the
needs of your userbase precisely, maybe you could get away with it.

			regards, tom lane