Re: no default hash partition

2019-08-08 Thread Alvaro Herrera
On 2019-Aug-08, Amit Langote wrote: > On Thu, Aug 8, 2019 at 6:22 AM Tom Lane wrote: > > OK, but maybe also s/created as a default partition/created as the default > > partition/ ? Writing "a" carries the pretty clear implication that there > > can be more than one, and contradicting that a sen

Re: no default hash partition

2019-08-07 Thread Amit Langote
On Thu, Aug 8, 2019 at 6:22 AM Tom Lane wrote: > Alvaro Herrera writes: > > On 2019-Aug-07, Tom Lane wrote: > >> Hm, that's rather confusingly worded IMO. Is the antecedent of "this > >> option" just DEFAULT, or does it mean that you can't use FOR VALUES, > >> or perchance it means that you can'

Re: no default hash partition

2019-08-07 Thread Tom Lane
Alvaro Herrera writes: > On 2019-Aug-07, Tom Lane wrote: >> Hm, that's rather confusingly worded IMO. Is the antecedent of "this >> option" just DEFAULT, or does it mean that you can't use FOR VALUES, >> or perchance it means that you can't use a PARTITION OF clause >> at all? > Uh, you're right

Re: no default hash partition

2019-08-07 Thread Tom Lane
Alvaro Herrera writes: > Actually, it also says this (in the blurb for the PARTITION OF clause): > Creates the table as a partition of the specified > parent table. The table can be created either as a partition for > specific > values using FOR VALUES or as a default partition

Re: no default hash partition

2019-08-07 Thread Alvaro Herrera
On 2019-Aug-07, Tom Lane wrote: > Alvaro Herrera writes: > > Actually, it also says this (in the blurb for the PARTITION OF clause): > > > Creates the table as a partition of the > > specified > > parent table. The table can be created either as a partition for > > specific > >

Re: no default hash partition

2019-08-07 Thread Alvaro Herrera
On 2019-Aug-07, Amit Langote wrote: > That hash-partitioned tables can't have default partition is mentioned > in the CREATE TABLE page: > > "If DEFAULT is specified, the table will be created as a default > partition of the parent table. The parent can either be a list or > range partitioned tab

Re: no default hash partition

2019-08-07 Thread Alvaro Herrera
On 2019-Aug-06, Stephen Frost wrote: > Yeah, that's a fair argument, but giving the user a way to say that > would address it. As in, "create me a list-partitioned table for these > values, plus a default." Anyhow, I'm sure that I'm taking this beyond > what we need to do right now, just sharing

Re: no default hash partition

2019-08-07 Thread Alvaro Herrera
On 2019-Aug-07, Amit Langote wrote: > That hash-partitioned tables can't have default partition is mentioned > in the CREATE TABLE page: > > "If DEFAULT is specified, the table will be created as a default > partition of the parent table. The parent can either be a list or > range partitioned tab

Re: no default hash partition

2019-08-07 Thread Stephen Frost
Greetings, * Amit Langote (amitlangot...@gmail.com) wrote: > On Wed, Aug 7, 2019 at 1:59 PM Kyotaro Horiguchi > wrote: > > At Tue, 6 Aug 2019 23:26:19 -0400, Robert Haas > > wrote: > > > On Tue, Aug 6, 2019 at 6:58 PM Tom Lane wrote: > > > I think, as Amit says, that having an automatic partit

Re: no default hash partition

2019-08-07 Thread Magnus Hagander
On Wed, Aug 7, 2019 at 5:26 AM Robert Haas wrote: > On Tue, Aug 6, 2019 at 6:58 PM Tom Lane 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 par

Re: no default hash partition

2019-08-06 Thread Amit Langote
Horiguchi-san, On Wed, Aug 7, 2019 at 1:59 PM Kyotaro Horiguchi wrote: > At Tue, 6 Aug 2019 23:26:19 -0400, Robert Haas wrote: > > On Tue, Aug 6, 2019 at 6:58 PM Tom Lane wrote: > > I think, as Amit says, that having an automatic partition creation > > feature for hash partitions (and maybe oth

Re: no default hash partition

2019-08-06 Thread Kyotaro Horiguchi
At Tue, 6 Aug 2019 23:26:19 -0400, Robert Haas wrote in > On Tue, Aug 6, 2019 at 6:58 PM Tom Lane wrote: > I think, as Amit says, that having an automatic partition creation > feature for hash partitions (and maybe other kinds, but certainly for > hash) would be a useful thing to add to the sys

Re: no default hash partition

2019-08-06 Thread David Fetter
On Tue, Aug 06, 2019 at 06:58:44PM -0400, Tom Lane wrote: > Alvaro Herrera writes: > > On 2019-Aug-06, Tom Lane wrote: > >> Seems like "it's likely to cause trouble for users" is just going to > >> beg the question "why?". Can we explain the hazard succinctly? > >> Or point to a comment somewhere

Re: no default hash partition

2019-08-06 Thread Robert Haas
On Tue, Aug 6, 2019 at 6:58 PM Tom Lane 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,

Re: no default hash partition

2019-08-06 Thread Amit Langote
Hi, On Wed, Aug 7, 2019 at 8:02 AM Stephen Frost wrote: > * Tom Lane (t...@sss.pgh.pa.us) wrote: > > Alvaro Herrera writes: > > > On 2019-Aug-06, Tom Lane wrote: > > >> Seems like "it's likely to cause trouble for users" is just going to > > >> beg the question "why?". Can we explain the hazard

Re: no default hash partition

2019-08-06 Thread Amit Langote
a given parent table." > How about the attached? Does anyone see > a reason to make this more verbose, and if so to what? If the outcome of this discussion is that we expand our internal documentation of why there's no default hash partition, then should we also expand the user documentation somehow? Thanks, Amit

Re: no default hash partition

2019-08-06 Thread Stephen Frost
Greetings, * Tom Lane (t...@sss.pgh.pa.us) wrote: > Stephen Frost writes: > > * Tom Lane (t...@sss.pgh.pa.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 crea

Re: no default hash partition

2019-08-06 Thread Tom Lane
Stephen Frost writes: > * Tom Lane (t...@sss.pgh.pa.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

Re: no default hash partition

2019-08-06 Thread Stephen Frost
Greetings, * Tom Lane (t...@sss.pgh.pa.us) wrote: > Alvaro Herrera writes: > > On 2019-Aug-06, Tom Lane wrote: > >> Seems like "it's likely to cause trouble for users" is just going to > >> beg the question "why?". Can we explain the hazard succinctly? > >> Or point to a comment somewhere else t

Re: no default hash partition

2019-08-06 Thread Tom Lane
Alvaro Herrera writes: > On 2019-Aug-06, Tom Lane wrote: >> Seems like "it's likely to cause trouble for users" is just going to >> beg the question "why?". Can we explain the hazard succinctly? >> Or point to a comment somewhere else that explains it? > Right ... the "trouble" is just that if t

Re: no default hash partition

2019-08-06 Thread Alvaro Herrera
On 2019-Aug-06, Tom Lane wrote: > Alvaro Herrera writes: > > Given the discussion starting at > > https://postgr.es/m/cafjfprdbiqjzm8sg9+s0x8re-afhds6mflgguw0wvunlgrv...@mail.gmail.com > > we don't have default-partition support with the hash partitioning > > scheme. That seems a reasonable outc

Re: no default hash partition

2019-08-06 Thread Tom Lane
Alvaro Herrera writes: > Given the discussion starting at > https://postgr.es/m/cafjfprdbiqjzm8sg9+s0x8re-afhds6mflgguw0wvunlgrv...@mail.gmail.com > we don't have default-partition support with the hash partitioning > scheme. That seems a reasonable outcome, but I think we should have a > comment

no default hash partition

2019-08-06 Thread Alvaro Herrera
Given the discussion starting at https://postgr.es/m/cafjfprdbiqjzm8sg9+s0x8re-afhds6mflgguw0wvunlgrv...@mail.gmail.com we don't have default-partition support with the hash partitioning scheme. That seems a reasonable outcome, but I think we should have a comment about it (I had to search the rea