Re: Indexes mysteriously change to ON ONLY

Rumpi Gravenstein <rgravens(at)gmail(dot)com> writes:
> We are using the pg_indexes view (indexdef) to retrieve the index
> definition.

Ah.

> Are you saying that as a normal part of building an index, there are short
> periods of time where the pg_indexes view will show the index with ON ONLY
> specified?

No, there's no "short periods", this is what it shows. That's partly
because the output is designed for pg_dump to use. But there's
a reasonably good argument for it anyway, which is that if you just
say "create index" then that's effectively a macro for building the
whole partitioned index set. That pg_indexes entry is only about the
top-level "virtual" index, and there are other entries for the leaf
indexes. For example,

regression=# create table foo (f1 int primary key) partition by list (f1);
CREATE TABLE
regression=# create table foo_1 partition of foo for values in (1);
CREATE TABLE
regression=# create table foo_2 partition of foo for values in (2);
CREATE TABLE
regression=# select tablename,indexname,indexdef from pg_indexes where indexname like 'foo%';
tablename | indexname | indexdef
-----------+------------+------------------------------------------------------------------
foo | foo_pkey | CREATE UNIQUE INDEX foo_pkey ON ONLY public.foo USING btree (f1)
foo_1 | foo_1_pkey | CREATE UNIQUE INDEX foo_1_pkey ON public.foo_1 USING btree (f1)
foo_2 | foo_2_pkey | CREATE UNIQUE INDEX foo_2_pkey ON public.foo_2 USING btree (f1)
(3 rows)

If you wanted to reconstruct this from individual parts, as pg_dump does,
you'd issue those commands and then connect them together with ATTACH
PARTITION commands.

regards, tom lane