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Thread: Sequence generating negative numbers

Sequence generating negative numbers

From
Shantanu Shekhar
Date:
Team,

I have a sequence definition in Postgres 9.6.11 like so:

CREATE SEQUENCE IF NOT EXISTS org.my_seq
  INCREMENT 1
  MINVALUE 1
  NO MAXVALUE
  START 1
  CACHE 20;

This sequence is used by a Java ORM framework to generate primary keys for one of our tables. The initial numbers generated by this sequence are as shown below:

-28 -27 -26 -25 -8 -7 1 2 52 53 72 92 93 94 112 113 132 133 152 172 192 193 212

I am unable to understand why the sequence would start with a negative number, particularly when the definition explicitly asks the sequence to start at 1. This has happened consistently in all of our environments. 

Thanks,

Shantanu

Re: Sequence generating negative numbers

From
Adrian Klaver
Date:
On 8/19/20 3:15 PM, Shantanu Shekhar wrote:
> Team,
> 
> I have a sequence definition in Postgres 9.6.11 like so:
> 
> CREATE SEQUENCE IF NOT EXISTS org.my_seq
>    INCREMENT 1
>    MINVALUE 1
>    NO MAXVALUE
>    START 1
>    CACHE 20;
> 
> This sequence is used by a Java ORM framework to generate primary keys 
> for one of our tables. The initial numbers generated by this sequence 
> are as shown below:
> 
> -28 -27 -26 -25 -8 -7 1 2 52 53 72 92 93 94 112 113 132 133 152 172 192 
> 193 212
> 
> I am unable to understand why the sequence would start with a negative 
> number, particularly when the definition explicitly asks the sequence to 
> start at 1. This has happened consistently in all of our environments.

Because something in the ORM is generating negative numbers and 
supplying then directly to the PK field.

> 
> Thanks,
> 
> Shantanu


-- 
Adrian Klaver
adrian.klaver@aklaver.com

Re: Sequence generating negative numbers

From
Adrian Klaver
Date:
On 8/19/20 3:24 PM, Shantanu Shekhar wrote:
Please reply to list also.
Ccing list.

> Thanks Adrian,
> 
> I will reach out to the ORM team and see if they can help me understand 
> this behavior.

I should have asked earlier, is this sequence set as a DEFAULT on the PK 
field or is it just being used by code to get numbers?

> 
> Shantanu
> On Wednesday, August 19, 2020, 06:20:27 PM EDT, Adrian Klaver 
> <adrian.klaver@aklaver.com> wrote:
> 
> 
> On 8/19/20 3:15 PM, Shantanu Shekhar wrote:
>  > Team,
>  >
>  > I have a sequence definition in Postgres 9.6.11 like so:
>  >
>  > CREATE SEQUENCE IF NOT EXISTS org.my_seq
>  >    INCREMENT 1
>  >    MINVALUE 1
>  >    NO MAXVALUE
>  >    START 1
>  >    CACHE 20;
>  >
>  > This sequence is used by a Java ORM framework to generate primary keys
>  > for one of our tables. The initial numbers generated by this sequence
>  > are as shown below:
>  >
>  > -28 -27 -26 -25 -8 -7 1 2 52 53 72 92 93 94 112 113 132 133 152 172 192
>  > 193 212
>  >
>  > I am unable to understand why the sequence would start with a negative
>  > number, particularly when the definition explicitly asks the sequence to
>  > start at 1. This has happened consistently in all of our environments.
> 
> Because something in the ORM is generating negative numbers and
> supplying then directly to the PK field.
> 
> 
>  >
>  > Thanks,
>  >
>  > Shantanu
> 
> 
> 
> -- 
> Adrian Klaver
> adrian.klaver@aklaver.com <mailto:adrian.klaver@aklaver.com>
> 
> 
> 


-- 
Adrian Klaver
adrian.klaver@aklaver.com

Re: Sequence generating negative numbers

From
Shantanu Shekhar
Date:
Adrian,

The sequence is not set as a default on PK. The sequence is exclusively being used by the ORM. 

Thanks,

Shantanu

On Wednesday, August 19, 2020, 06:28:53 PM EDT, Adrian Klaver <adrian.klaver@aklaver.com> wrote:


On 8/19/20 3:24 PM, Shantanu Shekhar wrote:
Please reply to list also.
Ccing list.

> Thanks Adrian,
>
> I will reach out to the ORM team and see if they can help me understand
> this behavior.

I should have asked earlier, is this sequence set as a DEFAULT on the PK
field or is it just being used by code to get numbers?

>
> Shantanu
> On Wednesday, August 19, 2020, 06:20:27 PM EDT, Adrian Klaver
> <adrian.klaver@aklaver.com> wrote:
>
>
> On 8/19/20 3:15 PM, Shantanu Shekhar wrote:
>  > Team,
>  >
>  > I have a sequence definition in Postgres 9.6.11 like so:
>  >
>  > CREATE SEQUENCE IF NOT EXISTS org.my_seq
>  >    INCREMENT 1
>  >    MINVALUE 1
>  >    NO MAXVALUE
>  >    START 1
>  >    CACHE 20;
>  >
>  > This sequence is used by a Java ORM framework to generate primary keys
>  > for one of our tables. The initial numbers generated by this sequence
>  > are as shown below:
>  >
>  > -28 -27 -26 -25 -8 -7 1 2 52 53 72 92 93 94 112 113 132 133 152 172 192
>  > 193 212
>  >
>  > I am unable to understand why the sequence would start with a negative
>  > number, particularly when the definition explicitly asks the sequence to
>  > start at 1. This has happened consistently in all of our environments.
>
> Because something in the ORM is generating negative numbers and
> supplying then directly to the PK field.
>
>
>  >
>  > Thanks,
>  >
>  > Shantanu
>
>
>
> --
> Adrian Klaver
> adrian.klaver@aklaver.com <mailto:adrian.klaver@aklaver.com>

>
>
>


--
Adrian Klaver
adrian.klaver@aklaver.com


Re: Sequence generating negative numbers

From
Adrian Klaver
Date:
On 8/20/20 9:21 AM, Shantanu Shekhar wrote:
> Adrian,
> 
> The sequence is not set as a default on PK. The sequence is exclusively 
> being used by the ORM.

Then something there is generating negative numbers and using them to 
populate the PK.

> 
> Thanks,


-- 
Adrian Klaver
adrian.klaver@aklaver.com