Re: [Postgres-xc-developers] Issues with Sequences with negative increments

[Nikhil S. <ni...@st...>]

The currval() logic also has a similar issue.

Regards,
Nikhils


On Mon, Apr 22, 2013 at 6:18 AM, 鈴木 幸市 <ko...@in...> wrote:

> I'm afraid the cause is not only by gym.   If min_value is not specified
> (or specified as "invalid" value), gtm assigns -0x7ffffffffffffffeLL as the
> minimum value of the sequence (see gtm_seq.[ch]).    So I suspect that
> minimum value will be specified by DDL in the coordinator.
>
> You fix is very welcome.
>
> GTM in the current master has a backup feature which dumps next restore
> point of gxid and each sequence to gtm.control.   I hope this helps tests
> to some extent.
>
> Regards;
>  ---
> Koichi Suzuki
>
>
>
> On 2013/04/22, at 8:32, Michael Paquier <mic...@gm...> wrote:
>
>
>
>
> On Mon, Apr 22, 2013 at 3:57 AM, Nikhil Sontakke <ni...@st...>wrote:
>
>> Hi all,
>>
>> Consider the following:
>>
>> create sequence seqname increment by -2;
>> select nextval('seqname');
>> ERROR:  GTM error, could not obtain sequence value
>>
>> The above should have returned -1.
>>
>> ISTM, the sequence fetching logic on the backend side has been coded
>> entirely with the assumption that sequences can never have negative values.
>> So a less than 0 value returned from get_next() is assumed to be a problem!
>> That's completely wrong. We need to deal with this properly. I will submit
>> a patch for this when I get some time soon.
>>
> Adding a regression test in xc_sequence.sql would also be good to cover
> this case as this is caused by xc-only code.
> --
> Michael
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