RE: Fix for segfault in logical replication on master

On Thursday, June 17, 2021 1:31 PM Mark Dilger <mark.dilger@enterprisedb.com> wrote:
> In commit e7eea52b2d, you introduced a new function,
> RelationGetIdentityKeyBitmap(), which uses some odd logic for determining
> if a relation has a replica identity index.  That code segfaults under certain
> conditions.  A test case to demonstrate that is attached.  Prior to patching
> the code, this new test gets stuck waiting for replication to finish, which never
> happens.  You have to break out of the test and check
> tmp_check/log/021_no_replica_identity_publisher.log.
> 
> I believe this bit of logic in src/backend/utils/cache/relcache.c:
> 
>       indexDesc = RelationIdGetRelation(relation->rd_replidindex);
>       for (i = 0; i < indexDesc->rd_index->indnatts; i++)
> 
> is unsafe without further checks, also attached.
> 
> Would you mind taking a look?
Hi, Mark

Thanks for your reporting.
I started to analyze your report and
will reply after my idea to your modification is settled.

Best Regards,
    Takamichi Osumi