On March 24, 2015 12:35:28 PM GMT+01:00, Michael Paquier <michael.paquier@gmail.com> wrote: >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.
I think Thom's point is that he promoted the node...
Thom, are you sure this want transient?
The index is unlogged until reindexing...
# select oid, relname, relpersistence from pg_class where relname in ('test','test_pkey','utest','utest_pkey'); oid | relname | relpersistence -------+------------+---------------- 16387 | test | p 16394 | test_pkey | p 16398 | utest | u 16405 | utest_pkey | u (4 rows)
# reindex index utest_pkey; REINDEX
# select oid, relname, relpersistence from pg_class where relname in ('test','test_pkey','utest','utest_pkey'); oid | relname | relpersistence -------+------------+---------------- 16387 | test | p 16394 | test_pkey | p 16398 | utest | u 16405 | utest_pkey | p (4 rows)
Which is think also raises the question, why are unlogged indexes made persistent by a reindex?
I should also mention that it becomes unlogged again when running VACUUM FULL or CLUSTER on the table.