Re: Partitioning: issues/ideas (Was: Re: On partitioning)

On 27-01-2015 AM 05:46, Jim Nasby wrote:
> On 1/25/15 7:42 PM, Amit Langote wrote:
>> On 21-01-2015 PM 07:26, Amit Langote wrote:
>>> Ok, I will limit myself to focusing on following things at the moment:
>>>
>>> * Provide syntax in CREATE TABLE to declare partition key
>>
>> While working on this, I stumbled upon the question of how we deal with
>> any index definitions following from constraints defined in a CREATE
>> statement. I think we do not want to have a physical index created for a
>> table that is partitioned (in other words, has no heap of itself). As
>> the current mechanisms dictate, constraints like PRIMARY KEY, UNIQUE,
>> EXCLUSION CONSTRAINT are enforced as indexes. It seems there are really
>> two decisions to make here:
>>
>> 1) how do we deal with any index definitions (either explicit or
>> implicit following from constraints defined on it) - do we allow them by
>> marking them specially, say, in pg_index, as being mere
>> placeholders/templates or invent some other mechanism?
>>
>> 2) As a short-term solution, do we simply reject creating any indexes
>> (/any constraints that require them) on a table whose definition also
>> includes PARTITION ON clause? Instead define them on its partitions (or
>> any relations in hierarchy that are not further partitioned).
>>
>> Or maybe I'm missing something...
>
> Wasn't the idea that the parent table in a partitioned table wouldn't
> actually have a heap of it's own? If there's no heap there can't be an
> index.
>

Yes, that's right. Perhaps, we should look at heap-less partitioned
relation thingy not so soon as you say below.

> That said, I think this is premature optimization that could be done later.

It seems so.

Thanks,
Amit