Hi, On 2019-03-06 19:45:06 +1300, David Rowley wrote: > Over on [1] Andres pointed out that the pg_dump support for the new to > PG12 tablespace inheritance feature is broken. This is the feature > added in ca4103025dfe26 to allow a partitioned table to have a > tablespace that acts as the default tablespace for newly attached > partitions. The idea being that you can periodically change the > default tablespace for new partitions to a tablespace that sits on a > disk partition with more free space without affecting the default > tablespace for normal non-partitioned tables. Anyway...
I'm also concerned that the the current catalog representation isn't right. As I said: > I also find it far from clear that: > <listitem> > <para> > The <replaceable class="parameter">tablespace_name</replaceable> is the > name > of the tablespace in which the new table is to be created. > If not specified, > <xref linkend="guc-default-tablespace"/> is consulted, or > <xref linkend="guc-temp-tablespaces"/> if the table is temporary. For > partitioned tables, since no storage is required for the table itself, > the tablespace specified here only serves to mark the default tablespace > for any newly created partitions when no other tablespace is explicitly > specified. > </para> > </listitem> > is handled correctly. The above says that the *specified* tablespaces - > which seems to exclude the default tablespace - is what's going to > determine what partitions use as their default tablespace. But in fact > that's not true, the partitioned table's pg_class.retablespace is set to > what default_tablespaces was at the time of the creation. I still think the feature as is doesn't seem to have very well defined behaviour. > If we instead did: > > CREATE TABLE public.listp1 (a integer > ); > > ALTER TABLE public.list1 ATTACH PARTITION public.listp FOR VALUES IN (1); Isn't that a bit more expensive, because now the table needs to be scanned for maching the value? That's probably neglegible though, given it'd probably always empty. Greetings, Andres Freund
