Re: ALTER TABLE ... ALTER COLUMN ... SET DISTINCT

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: ITAGAKI Takahiro <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>, PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: ALTER TABLE ... ALTER COLUMN ... SET DISTINCT
Date: 2009-04-06 14:49:49
Message-ID: 29249.1239029389@sss.pgh.pa.us
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-hackers

Robert Haas <robertmhaas(at)gmail(dot)com> writes:
> Well, I think I was pretty clear about what I was trying to
> accomplish. I think there are more people who care about pg_dump
> output being diffable than there are who need to set ndistinct more
> accurately than 1 ppm and yet not as an integer.

My, you *are* paranoid about float4 aren't you? Once you've stored
a given value, it's always going to dump the same. Diffing different
dumps isn't going to be a problem. I concede that it might look
different from what you put in originally, but we make no effort to
guarantee that for DDL anyway.

(It is true that with pg_dump's default float_extra_digits setting,
outputs from this column might look uglier than they need to.
I don't see anything wrong with having pg_dump forcibly round the
value to five or so digits, though.)

regards, tom lane

In response to

Responses

Browse pgsql-hackers by date

  From Date Subject
Next Message Stephen Frost 2009-04-06 14:50:53 Re: ALTER TABLE ... ALTER COLUMN ... SET DISTINCT
Previous Message Robert Haas 2009-04-06 14:35:24 Re: ALTER TABLE ... ALTER COLUMN ... SET DISTINCT