Re: md5 of table - Mailing list pgsql-general

From Robert Treat
Subject Re: md5 of table
Date
Msg-id CABV9wwN7QWYUFDVJW39wh=5xr5zPD10jcux7JE+E9-HKWuQOUA@mail.gmail.com
Whole thread Raw
In response to Re: md5 of table  (Merlin Moncure <mmoncure@gmail.com>)
List pgsql-general
2011/9/1 Merlin Moncure <mmoncure@gmail.com>:
> 2011/9/1 Grzegorz Jaśkiewicz <gryzman@gmail.com>:
>> On Thu, Sep 1, 2011 at 11:14 AM, Sim Zacks <sim@compulab.co.il> wrote:
>>> On 09/01/2011 12:26 PM, Pavel Stehule wrote:
>>>>
>>>> Hello
>>>>
>>>> postgres=# create table tt(a int, b varchar);
>>>> CREATE TABLE
>>>> postgres=# insert into tt values(10,'hello');
>>>> INSERT 0 1
>>>>
>>>> postgres=# select md5(array_to_string(array_agg(md5(tt::text)),'')) from
>> I do that as well, but it might have questionable performance when
>> your table has 16M rows, and is 50GB +
>
> you need order by for that to work.  I would do it like this:
> select md5(array(select foo from foo order by foo_pkey)::text);
>
> it's great quick'n'dirty, but not much scalable beyond millions.

I've always liked doing this with my pager:

 [robert@client-168] export PAGER=md5
-=[11:40:25 Thu Sep 01]=---=[ pagila-0.10.1 ]=-
 [robert@client-168] psql -hlocalhost -dpagila
psql (9.0.4, server 9.1beta3)
WARNING: psql version 9.0, server version 9.1.
         Some psql features might not work.
Type "help" for help.

pagila=# select * from actor order by actor_id;
f381ebdefe0aada9c0bc14e657962c1f


Robert Treat
conjecture: xzilla.net
consulting: omniti.com

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