Re: Re: User defined data types in Logical Replication

On Wed, Nov 22, 2017 at 12:25 AM, Huong Dangminh
<huo-dangminh(at)ys(dot)jp(dot)nec(dot)com> wrote:
> Thanks for your response.
> # And sorry again because I could not reply to your gmail
> # address from my environment due to security restriction.

It's okay. I can understand your environment :-)

> Sorry for not replying sooner.
>
>> > Attached draft patch fixed this issue, at least on my environment.
>>
>> It works good for me.
>>
>> > Please review it.
>>
>> I will review it soon.
>
> There is one more case that user-defined data type is not supported in Logical Replication.
> That is when remote data type's name does not exist in SUBSCRIBE.
>
> In relation.c:logicalrep_typmap_gettypname
> We search OID in syscache by remote's data type name and mapping it, if it does not exist in syscache
> We will be faced with the bellow error.
>
> if (!OidIsValid(entry->typoid))
> ereport(ERROR,
> (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
> errmsg("data type \"%s.%s\" required for logical replication does not exist",
> entry->nspname, entry->typname)));
>
> I think, it is not necessary to check typoid here in order to avoid above case, is that right?

I think it's not right. We should end up with an error in the case
where the same type name doesn't exist on subscriber. With your
proposed patch, logicalrep_typmap_gettypname() can return an invalid
string (entry->typname) in that case, which can be a cause of SEGV.

> Sorry, I have added this thread to the next CF.

Thank you for adding it.

Regards,

--
Masahiko Sawada
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center