Re: [OSSTEST PATCH 0/1] PostgreSQL db: Retry on constraint violation [and 2 more messages]

On Wed, Dec 14, 2016 at 9:40 AM, Kevin Grittner <kgrittn@gmail.com> wrote:
> On Wed, Dec 14, 2016 at 8:27 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>> But even after that fix, at the least, you'll still be able to
>> demonstrate the same problem by trapping serialization_failure rather
>> than unique_constraint.
>
> I hope not; the "doomed" flag associated with a serializable
> transaction should cause another attempt to cancel the transaction
> at every subsequent opportunity, including commit.  While we're
> digging into bugs in this area it wouldn't hurt (as I said in my
> prior post) to confirm that this is being handled everywhere it
> should be, but I'd be kinda surprised if it wasn't.

Oh, hmm.  So you're saying that if I begin a subtransaction, read some
data that causes a serialization anomaly, and then rollback the
subtransaction, my toplevel transaction is now doomed?  If so, then
isn't that a counterexample to my proposition that a read-only
transaction can't be cancelled at commit time?

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