From: Tom Lane <tgl@sss.pgh.pa.us>
To: Jim Nasby <Jim.Nasby@BlueTreble.com>
cc: emre@hasegeli.com, Matthias Kurz <m.kurz@irregular.at>,
        =?UTF-8?Q?Dagfinn_Ilmari_Manns=c3=a5ker?= <ilmari@ilmari.org>,
        Andrew Dunstan <andrew@dunslane.net>,
        Robert Haas <robertmhaas@gmail.com>,
        PostgreSQL Hackers <pgsql-hackers@postgresql.org>,
        "David G. Johnston" <david.g.johnston@gmail.com>
Subject: Re: [PATCH] Alter or rename enum value
In-reply-to: <b942ad05-abae-e183-5d28-f6b66ab21a97@BlueTreble.com>
References: 
 <CAO=2mx6uvgPaPDf-rHqG8=1MZnGyVDMQeh8zS4euRyyg4D35OQ@mail.gmail.com>
 <CAO=2mx6rK_h4BC7y+3Nu-8fuZJXdFjd9FE_MZnzkH+vnMp0C-Q@mail.gmail.com>
 <d8ja8ln7nl0.fsf@dalvik.ping.uio.no> <d8jk2kn4yn0.fsf_-_@dalvik.ping.uio.no>
 <d8jeg5m4as8.fsf@dalvik.ping.uio.no>
 <CAE2gYzxo4bB_uQDafQYoGx=WmUrO-NFUbKBYfu4j_=LfaaUzFg@mail.gmail.com>
 <d8jy43m2wow.fsf@dalvik.ping.uio.no>
 <CAE2gYzy9fWFmMgnA0DstcGdtuFv40d3JXgtikE-ywtZ2qow=ng@mail.gmail.com>
 <26875.1472935684@sss.pgh.pa.us>
 <CAE2gYzzoWnzmz3MhiSr_49Mjjah4KXju-N81Bjc9p95-YcxpcA@mail.gmail.com>
 <32710.1473099022@sss.pgh.pa.us>
 <CA+Tgmoaz9OSD1Zbf4kMfEDV8OMGM6x2=kWxAxd1XPCfTWW1f8Q@mail.gmail.com>
 <8384.1473186627@sss.pgh.pa.us>
 <9dd58b5f-0447-54fe-02f4-afb62fd7c3c8@dunslane.net>
 <17893.1473193170@sss.pgh.pa.us> <d8jk2eoyn5u.fsf@dalvik.ping.uio.no>
 <30073.1473279258@sss.pgh.pa.us>
 <CAO=2mx6wDD3kA+XfJ6Lo9y3ENi3R4v_ZBmatb_58X99A-zQZJg@mail.gmail.com>
 <CAE2gYzy2U60yhj9fpSciO+cF8AVd2_V++d6GZUiC3NeG8sWwvA@mail.gmail.com>
 <b942ad05-abae-e183-5!
 d28-f6b66ab21a97@BlueTreble.com>
Comments: In-reply-to Jim Nasby <Jim.Nasby@BlueTreble.com>
	message dated "Sat, 10 Sep 2016 22:05:58 -0500"
Date: Sun, 11 Sep 2016 10:34:57 -0400
Message-ID: <23103.1473604497@sss.pgh.pa.us>
Precedence: bulk
Sender: pgsql-hackers-owner@postgresql.org

Jim Nasby <Jim.Nasby@BlueTreble.com> writes:
> On 9/8/16 4:55 AM, Emre Hasegeli wrote:
>> The main problem that has been discussed before was the indexes.  One
>> way is to tackle with it is to reindex all the tables after the
>> operation.  Currently we are doing it when the datatype of indexed
>> columns change.  So it should be possible, but very expensive.

> Why not just disallow dropping a value that's still in use? That's 
> certainly what I would prefer to happen by default...

Even ignoring the hidden-values-in-indexes problem, how would you
discover that it's still in use?  Not to mention preventing new
insertions after you look?

			regards, tom lane


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