From: | Csaba Ragasits <ragasits(dot)csaba(at)gmail(dot)com> |
---|---|
To: | pgsql-general(at)lists(dot)postgresql(dot)org |
Subject: | Re: PG8.3->10 migration data differences |
Date: | 2018-09-10 13:43:49 |
Message-ID: | CANaXbVjbqvvFUGWpZwTdghxEW82GBLwQxFUKopmRBdnrAvDe_Q@mail.gmail.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-general |
I think I found the solution.
When I set this parameter on the pg10 client connection, the pg10 REAL
value format same as the pg83 value:
SET extra_float_digits = 0;
Interesting, because the default value is 0 in the postgresql.conf:
#extra_float_digits = 0 # min -15, max 3
Do you have any ideas how can I format the miliseconds too?
Thx,
Csaba
2018-09-10 12:00 GMT+02:00 Peter J. Holzer <hjp-pgsql(at)hjp(dot)at>:
> On 2018-09-10 11:57:42 +0300, Achilleas Mantzios wrote:
> > On 10/09/2018 11:22, Csaba Ragasits wrote:
> > Hello,
> >
> > We would like to migrate our old databases to new postgres server,
> > with the simple backup-restore process. The process run fine
> > without errors but when we're checking the source and the
> > migrated datas as field level, we found the following differences:
> [...]
> >
> > Field type: REAL
> > pg93: 2.2
> > pg10: 2.20000005
> >
> >
> > Those have to do with rounding. Precision for real is 6 decimal
> > digits. Your difference is on the 8-th digit.
>
> Nitpick: Precision is 24 binary digits which is *about* 6 decimal
> digits. The number which is actually stored (on both pg93 and pg10) is
> actually 2.2000000476837158203125 (1.00011001100110011001101 * 2^1 in
> binary). Apparently Pg9.3 rounds this to "2.2" on output while Pg10
> prints the more precise (but still not exact) "2.20000005".
>
> (I would argue that the Pg9.3 output is better, since it represents the
> same value in fewer digits, but always printing the minimum number of
> digits necessary is surprisingly difficult.)
>
> hp
>
> --
> _ | Peter J. Holzer | we build much bigger, better disasters now
> |_|_) | | because we have much more sophisticated
> | | | hjp(at)hjp(dot)at | management tools.
> __/ | http://www.hjp.at/ | -- Ross Anderson <https://www.edge.org/>
>
From | Date | Subject | |
---|---|---|---|
Next Message | Tom Lane | 2018-09-10 14:05:06 | Re: PG8.3->10 migration data differences |
Previous Message | Laurenz Albe | 2018-09-10 13:12:10 | Re: Why my query not doing index only scan |