Re: no default hash partition

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Stephen Frost <sfrost(at)snowman(dot)net>
Cc: Alvaro Herrera <alvherre(at)2ndquadrant(dot)com>, Pg Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: no default hash partition
Date: 2019-08-06 23:35:12
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Stephen Frost <sfrost(at)snowman(dot)net> writes:
> * Tom Lane (tgl(at)sss(dot)pgh(dot)pa(dot)us) wrote:
>> Hmm. So given the point about it being hard to predict which hash
>> partitions would receive what values ... under what circumstances
>> would it be sensible to not create a full set of partitions? Should
>> we just enforce that there is a full set, somehow?

> I imagine there's good reasons this wasn't just done (for this or
> various other things), but couldn't we enforce it by just creating them
> all..? Sure would simplify a lot of things for users. Similairly for
> list partitions, I would think.

Well, with lists Alvaro's point holds: you might know a priori that
some of the values are infrequent and don't deserve their own partition.
The thing about hash is that the entries should (in theory) get spread
out to all partitions pretty evenly, so it's hard to see why a user
would want to treat any partition differently from any other.

regards, tom lane

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