On Wed, Dec 10, 2014 at 12:33 PM, Amit Kapila <amit.kapil...@gmail.com> wrote: > On Tue, Dec 9, 2014 at 11:44 PM, Josh Berkus <j...@agliodbs.com> wrote: >> On 12/09/2014 12:17 AM, Amit Langote wrote: >> >> Now if user wants to define multi-column Partition based on >> >> > monthly_salary and annual_salary, how do we want him to >> >> > specify the values. Basically how to distinguish which values >> >> > belong to first column key and which one's belong to second >> >> > column key. >> >> > >> > Perhaps you are talking about "syntactic" difficulties that I totally >> > missed in my other reply to this mail? >> > >> > Can we represent the same data by rather using a subpartitioning scheme? >> > ISTM, semantics would remain the same. >> > >> > ... PARTITION BY (monthly_salary) SUBPARTITION BY (annual_salary)? >> > > Using SUBPARTITION is not the answer for multi-column partition, > I think if we have to support it for List partitioning then something > on lines what Josh has mentioned below could workout, but I don't > think it is important to support multi-column partition for List at this > stage. >
Yeah, I realize multicolumn list partitioning and list-list composite partitioning are different things in many respects. And given how awkward multicolumn list partitioning is looking to implement, I also think we only allow single column in a list partition key. >> ... or just use arrays. >> >> PARTITION BY LIST ( monthly_salary, annual_salary ) >> PARTITION salary_small VALUES ({[300,400],[5000,6000]}) >> ) .... >> >> ... but that begs the question of how partition by list over two columns >> (or more) would even work? You'd need an a*b number of partitions, and >> the user would be pretty much certain to miss a few value combinations. >> Maybe we should just restrict list partitioning to a single column for >> a first release, and wait and see if people ask for more? >> > > I also think we should not support multi-column list partition in first > release. > Yes. Thanks, Amit -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers