Re: REINDEX INDEX results in a crash for an index of pg_class since 9.6

On Tue, Apr 23, 2019 at 04:47:19PM -0400, Tom Lane wrote:
> regression=# reindex index pg_class_relname_nsp_index;
> REINDEX
> regression=# reindex index pg_class_oid_index;
> REINDEX
> regression=# reindex index pg_class_tblspc_relfilenode_index;
> REINDEX
> regression=# reindex table pg_class;
> REINDEX
> regression=# reindex index pg_class_tblspc_relfilenode_index;
> REINDEX
>
> Is there some precondition you're not mentioning?

Hm. In my own init scripts, I create a new database just after
starting the instance. That seems to help in reproducing the
failure, because each time I create a new database, connect to it and
reindex then I can see the crash. If I do a reindex of pg_class
first, I don't see a crash of some rebuilds already happened, but if I
do directly a reindex of one of the indexes first, then the failure is
plain. If I also add some regression tests, say in create_index.sql
to stress a reindex of pg_class and its indexes, the crash also shows
up. If I apply my previous patch to make CatalogIndexInsert() not do
an insert on a catalog index being rebuilt, then things turn to be
fine.
--
Michael