Re: Bug in to_timestamp().

I attached new patch "0001-to-timestamp-format-checking-v2.patch". It 
fixes behaviour for Amul's scenarious:

> Following are few scenarios where we break existing behaviour:
>
> SELECT TO_TIMESTAMP('2015-12-31 13:43:36', 'YYYY MM DD HH24 MI SS');
> SELECT TO_TIMESTAMP('2011$03!18 23_38_15', 'YYYY-MM-DD HH24:MI:SS');
> SELECT TO_TIMESTAMP('2011*03*18 23^38&15', 'YYYY-MM-DD HH24:MI:SS');
> SELECT TO_TIMESTAMP('2011*03!18 #%23^38$15', 'YYYY-MM-DD$$$HH24:MI:SS');
>
> But current patch behaviour is not that much bad either at least we have errors, but I am not sure about community acceptance.
>
> I would like to divert communities' attention on following case:
> SELECT TO_TIMESTAMP('2013--10-01', 'YYYY-MM-DD');

For queries above the patch gives an output without any error.

> Another is, shouldn’t we have error in following cases?
> SELECT TO_TIMESTAMP('2016-06-13 99:99:99', 'YYYY-MM-DD HH24:MI:SS');
> SELECT TO_TIMESTAMP('2016-02-30 15:43:36', 'YYYY-MM-DD HH24:MI:SS');

I attached second patch "0002-to-timestamp-validation-v2.patch". With it 
PostgreSQL perform additional checks for date and time. But as I wrote 
there is another patch in the thread "to_date_valid()" wich differs from 
this patch.

Sincerely,
-- 
Artur Zakirov
Postgres Professional: http://www.postgrespro.com
Russian Postgres Company