Re: Adding support for Default partition in partitioning

On Thu, Apr 27, 2017 at 8:49 AM, Rahila Syed <rahilasyed90(at)gmail(dot)com> wrote:
>>I suspect it could be done as of now, but I'm a little worried that it
>>might create grammar conflicts in the future as we extend the syntax
>>further. If we use CREATE TABLE ... PARTITION OF .. DEFAULT, then the
>>word DEFAULT appears in the same position where we'd normally have FOR
>>VALUES, and so the parser will definitely be able to figure out what's
>>going on. When it gets to that position, it will see FOR or it will
>>see DEFAULT, and all is clear. OTOH, if we use CREATE TABLE ...
>>DEFAULT PARTITION OF ..., then we have action at a distance: whether
>>or not the word DEFAULT is present before PARTITION affects which
>>tokens are legal after the parent table name. bison isn't always very
>>smart about that kind of thing. No particular dangers come to mind at
>>the moment, but it makes me nervous anyway.
>
> +1 for CREATE TABLE..PARTITION OF...DEFAULT syntax.
> I think substituting DEFAULT for FOR VALUES is appropriate as
> both cases are mutually exclusive.
>
> One more thing that needs consideration is should default partitions be
> partitioned further? Other databases allow default partitions to be
> partitioned further. I think, its normal for users to expect the data in
> default partitions to also be divided into sub partitions. So
> it should be supported.
> My colleague Rajkumar Raghuwanshi brought to my notice the current patch
> does not handle this correctly.
> I will include this in the updated patch if there is no objection.
>
> On the other hand if sub partitions of a default partition is to be
> prohibited,
> an error should be thrown if PARTITION BY is specified after DEFAULT.

I see no reason to prohibit it. You can further partition any other
kind of partition, so there seems to be no reason to disallow it in
this one case.

Are you also working on extending this to work with range
partitioning? Because I think that would be good to do.

--
Robert Haas
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