Re: 2PC support for pglogical

On Wed, Mar 23, 2016 at 1:44 AM, Craig Ringer <craig@2ndquadrant.com> wrote:
> On 10 March 2016 at 22:50, Stas Kelvich <s.kelvich@postgrespro.ru> wrote:
>> Hi.
>>
>> Here is proof-of-concept version of two phase commit support for logical
>> replication.
>
> I missed this when you posted it, so sorry for the late response.
>
> I've read through this but not tested it yet. I really appreciate you doing
> it, it's been on my wishlist/backburner for ages.
>
> On reading through the patch I noticed that there doesn't seem to be any
> consideration of locking. The prepared xact can still hold strong locks on
> catalogs. How's that handled? I think Robert's group locking stuff is what
> we'll want here - for a prepared xact we can join the prepared xact as a
> group lock member so we inherit its locks. Right now if you try DDL in a
> prepared xact I suspect it'll break.

I have grave doubts about that approach.  It's not impossible it could
be right, but I wouldn't bet the farm on it.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company