Обсуждение: [GENERAL] PG 10 - Trouble with overlap of range partition of two dimensions

On Tue, Oct 31, 2017 at 8:36 PM, Stephen Froehlich
<s.froehlich@cablelabs.com> wrote:
> CREATE TABLE lotsa_data_20171027_src3 PARTITION OF lotsa_data
>     FOR VALUES FROM ('2017-10-26 18:00:00-06', 3) TO ('2017-10-27
> 17:59:59.999-06', 3);
> ERROR: partition " lotsa_data_20171027_src1" would overlap partition
> "lotsa_data_20171027_src3"
>
> Why am I getting this error?

The answer is in the documentation:
https://www.postgresql.org/docs/devel/static/sql-createtable.html
The rules of such partitions is bound to row-wise comparisons. "For
example, given PARTITION BY RANGE (x,y), a partition bound FROM (1, 2)
TO (3, 4) allows x=1 with any y>=2, x=2 with any non-null y, and x=3
with any y<4."

So in your example and by comparing with the docs, the first partition
allows start_time = '2017-10-26 18:00:00-06' with source_no >= 1, and
the second partition allows source_no >= 3 which overlaps with the
first one.
-- 
Michael


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Hi Michael,

So if I'm reading this correctly, the proper way to do my use case is to use partitions of partitions, right?

--Stephen

-----Original Message-----
From: Michael Paquier [mailto:michael.paquier@gmail.com] 
Sent: Tuesday, October 31, 2017 4:06 PM
To: Stephen Froehlich <s.froehlich@cablelabs.com>
Cc: pgsql-general@postgresql.org
Subject: Re: [GENERAL] PG 10 - Trouble with overlap of range partition of two dimensions

On Tue, Oct 31, 2017 at 8:36 PM, Stephen Froehlich <s.froehlich@cablelabs.com> wrote:
> CREATE TABLE lotsa_data_20171027_src3 PARTITION OF lotsa_data
>     FOR VALUES FROM ('2017-10-26 18:00:00-06', 3) TO ('2017-10-27 
> 17:59:59.999-06', 3);
> ERROR: partition " lotsa_data_20171027_src1" would overlap partition 
> "lotsa_data_20171027_src3"
>
> Why am I getting this error?

The answer is in the documentation:
https://www.postgresql.org/docs/devel/static/sql-createtable.html
The rules of such partitions is bound to row-wise comparisons. "For example, given PARTITION BY RANGE (x,y), a
partitionbound FROM (1, 2) TO (3, 4) allows x=1 with any y>=2, x=2 with any non-null y, and x=3 with any y<4."
 

So in your example and by comparing with the docs, the first partition allows start_time = '2017-10-26 18:00:00-06'
withsource_no >= 1, and the second partition allows source_no >= 3 which overlaps with the first one.
 
--
Michael

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