Robert,
>
> I thought putting the partition boundaries into pg_inherits was a
> strange choice. I'd put it in pg_class, or in pg_partition if we
> decide to create that.
Hmm, yeah I guess we are better off using pg_inherits for just saying that a
partition is an inheritance child. Other details should go elsewhere for sure.
> Maybe as anyarray, but I think pg_node_tree
> might even be better. That can also represent data of some arbitrary
> type, but it doesn't enforce that everything is uniform. So you could
> have a list of objects of the form {RANGEPARTITION :lessthan {CONST
> ...} :partition 16982} or similar. The relcache could load that up
> and convert the list to a C array, which would then be easy to
> binary-search.
>
> As you say, you also need to store the relevant operator somewhere,
> and the fact that it's a range partition rather than list or hash,
> say.
>
I'm wondering here if it's better to keep partition values per partition
wherein we have two catalogs, say, pg_partitioned_rel and pg_partition_def.
pg_partitioned_rel stores information like partition kind, key (attribute
number(s)?), key opclass(es). Optionally, we could also say here if a given
record (in pg_partitioned_rel) represents an actual top-level partitioned table
or a partition that is sub-partitioned (wherein this record is just a dummy for
keys of sub-partitioning and such); something like partisdummy...
pg_partition_def stores information of individual partitions (/sub-partitions,
too?) such as its parent (either an actual top level partitioned table or a
sub-partitioning template), whether this is an overflow/default partition, and
partition values.
Such a scheme would be similar to what Greenplum [1] has.
Perhaps this duplicates inheritance and can be argued in that sense, though.
Do you think keeping partition defining values with the top-level partitioned
table would make some partitioning schemes (multikey, sub- , etc.) a bit
complicated to implement? I cannot offhand imagine the actual implementation
difficulties that might be involved myself but perhaps you have a better idea
of such details and would have a say...
Thanks,
Amit
[1]
http://gpdb.docs.pivotal.io/4330/index.html#ref_guide/system_catalogs/pg_partition_rule.html
http://gpdb.docs.pivotal.io/4330/index.html#ref_guide/system_catalogs/pg_partition.html
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