Re: Multi column range partition table

On Fri, Jun 23, 2017 at 6:58 AM, Amit Langote
<Langote_Amit_f8(at)lab(dot)ntt(dot)co(dot)jp> wrote:
> On 2017/06/22 20:48, amul sul wrote:
>> Hi,
>>
>> While working on the another patch, I came across the case where
>> I need an auto generated partition for a mutil-column range partitioned
>> table having following range bound:
>>
>> PARTITION p1 FROM (UNBOUNDED, UNBOUNDED) TO (10, 10)
>> PARTITION p2 FROM (10, 10) TO (10, UNBOUNDED)
>> PARTITION p3 FROM (10, UNBOUNDED) TO (20, 10)
>> PARTITION p4 FROM (20, 10) TO (20, UNBOUNDED)
>> PARTITION p5 FROM (20, UNBOUNDED) TO (UNBOUNDED, UNBOUNDED)
>>
>> In this, a lower bound of the partition is an upper bound of the
>> previous partition.
>>
>> While trying to create p3 partition with (10, UNBOUNDED) to (20, 10) bound,
>> got an overlap partition error.
>>
>> Here is the SQL to reproduced this error:
>>
>> CREATE TABLE range_parted ( i1 int, i2 int ) PARTITION BY RANGE (i1, i2);
>> CREATE TABLE p1 PARTITION OF range_parted FOR VALUES FROM (UNBOUNDED,
>> UNBOUNDED) TO (10, 10);
>> CREATE TABLE p2 PARTITION OF range_parted FOR VALUES FROM (10, 10) TO
>> (10, UNBOUNDED);
>> CREATE TABLE p3 PARTITION OF tab1 FOR VALUES FROM (10, UNBOUNDED) TO (20, 10);
>>
>> ERROR: partition "p3" would overlap partition "tab1_p_10_10"
>>
>> This happened because of UNBOUNDED handling, where it is a negative infinite
>> if it is in FROM clause. Wondering can't we explicitly treat this as
>> a positive infinite value, can we?
>
> No, we cannot. What would be greater than (or equal to) +infinite?
> Nothing. So, even if you will want p3 to accept (10, 9890148), it won't
> because 9890148 is not >= +infinite. It will accept only the rows where
> the first column is > 10 (second column is not checked in that case).
>
> You will have to define p3 as follows:
>
> CREATE TABLE p3 PARTITION OF tab1 FOR VALUES FROM (11, UNBOUNDED) TO (20, 10);
>
What if the partition key column is FLOAT ?

Regards,
Amul