Re: Error with index on unlogged table

On Tue, Mar 24, 2015 at 5:53 PM, Thom Brown <thom@linux.com> wrote:
> I was attempting to set up a data set to test pg_rewind, when I encountered
> an error.  I created a primary and standby, then:
>
> [...]
>
> # insert into utest (thing) values ('moomoo');
> ERROR:  index "utest_pkey" contains unexpected zero page at block 0
> HINT:  Please REINDEX it.
>
> This is built on commit e5f455f59fed0632371cddacddd79895b148dc07.

Unlogged tables are not in WAL, and cannot be accessed while in
recovery, so having an empty index relation is expected on a promoted
standby IMO. Now perhaps we could have a more friendly error message
in _bt_checkpage(), _hash_checkpage() and gistcheckpage() with an
additional HINT to mention unlogged tables, but I am not sure that
this is much worth it. Mentioning this behavior in the docs would be
good instead.
-- 
Michael