On Thu, 13 Apr 2017 16:40:29 -0400 Robert Haas <robertmh...@gmail.com> wrote:
> On Fri, Mar 17, 2017 at 7:57 AM, Yugo Nagata <nag...@sraoss.co.jp> wrote: > > I also understanded that my design has a problem during pg_dump and > > pg_upgrade, and that some information to identify the partition > > is required not depending the command order. However, I feel that > > Amul's design is a bit complicated with the rule to specify modulus. > > > > I think we can use simpler syntax, for example, as below. > > > > CREATE TABLE h1 PARTITION OF h FOR (0); > > CREATE TABLE h2 PARTITION OF h FOR (1); > > CREATE TABLE h3 PARTITION OF h FOR (2); > > I don't see how that can possibly work. Until you see all the table > partitions, you don't know what the partitioning constraint for any > given partition should be, which seems to me to be a fatal problem. If a partition has an id, the partitioning constraint can be written as hash_func(hash_key) % N = id wehre N is the number of paritions. Doesn't it work? > I agree that Amul's syntax - really, I proposed it to him - is not the > simplest, but I think all the details needed to reconstruct the > partitioning constraint need to be explicit. Otherwise, I'm pretty > sure things we're going to have lots of problems that we can't really > solve cleanly. We can later invent convenience syntax that makes > common configurations easier to set up, but we should invent the > syntax that spells out all the details first. I have a question about Amul's syntax. After we create partitions as followings, create table foo (a integer, b text) partition by hash (a); create table foo1 partition of foo with (modulus 2, remainder 0); create table foo2 partition of foo with (modulus 2, remainder 1); we cannot create any additional partitions for the partition. Then, after inserting records into foo1 and foo2, how we can increase the number of partitions? > > -- > Robert Haas > EnterpriseDB: http://www.enterprisedb.com > The Enterprise PostgreSQL Company -- Yugo Nagata <nag...@sraoss.co.jp> -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
