Re: Converting char to varchar automatically

From: Sergey Konoplev <gray(dot)ru(at)gmail(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Melvin Davidson <melvin6925(at)gmail(dot)com>, Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com>, hari(dot)fuchs(at)gmail(dot)com, "pgsql-general(at)postgresql(dot)org" <pgsql-general(at)postgresql(dot)org>
Subject: Re: Converting char to varchar automatically
Date: 2014-10-07 15:29:50
Message-ID: CAL_0b1vPsD1EpvkqO3M0LF2raRFj8hes=70F2w20=RxbpH1aNQ@mail.gmail.com
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BTW, where can I find a list of type1->type2 pairs that doesn't
require full table lock for conversion?

ps. Sorry for top posting.

On Mon, Oct 6, 2014 at 4:20 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Melvin Davidson <melvin6925(at)gmail(dot)com> writes:
>> Also, don't forget to test for relkind = 'r'. My bad from before.
>
> In principle you need to ignore attisdropped columns as well.
>
> Thinking about Jim's point about speed: it'd be wise to collapse any
> updates for multiple columns in the same table into one ALTER command,
> so that you only rewrite the table once, not once per column.
>
> regards, tom lane
>
>
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--
Kind regards,
Sergey Konoplev
PostgreSQL Consultant and DBA

http://www.linkedin.com/in/grayhemp
+1 (415) 867-9984, +7 (499) 346-7196, +7 (988) 888-1979
gray(dot)ru(at)gmail(dot)com

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