Just a bump on this --- perhaps the error is a bug with the DBMS?
From what I can see "speculative insertion changes" in this context means INSERT..ON CONFLICT DML. Although I have some experience writing extensions and simple patches for the code base, I don't know anything as a developer about the transaction log. I dug around a bit and it appears that there is a specific record type inside the WAL that differentiates INSERT from INSERT..ON CONFLICT changes, and it is these changes that cannot be re-ordered when trying to emit the message to the output plugin for the logical replication slot (which in this case is the internal pgoutput one). Given that, I don't see how it can be user error. Unless anyone else knows differently?
It will be useful if you could provide steps to reproduce this issue.
Thank you,
Rahila Syed
-Joe
On Tue, 31 Jan 2023, at 18:10, Joe Wildish wrote: > Hello, > > We have a logical replication publisher (13.7) and subscriber (14.6) > where we are seeing the following error on the subscriber. IP address > and publication name changed, otherwise verbatim: > > 2023-01-31 15:24:49 UTC:x.x.x.x(56276):super@pubdb:[1040971]: WARNING: > tables were not subscribed, you will have to run ALTER SUBSCRIPTION ... > REFRESH PUBLICATION to subscribe the tables > 2023-01-31 15:24:50 UTC::@:[1040975]: LOG: logical replication apply > worker for subscription "pub" has started > 2023-01-31 15:24:50 UTC::@:[1040975]: ERROR: could not receive data > from WAL stream: ERROR: invalid ordering of speculative insertion > changes > > This error occurs during the initial set up of the subscription. We > hit REFRESH, and then immediately it goes into this error state. It > then repeats as it is retrying from here onwards and keeps hitting the > same error. > > My understanding is that the subscriber is performing some kind of > reordering of the events contained within the WAL message. As it cannot > then consume the message, it aborts, retries, and gets the same message > and errors again. Looking in the source code it seems there is only > one place where this error can be emitted --- reorderbuffer.c:2179. > Moreover I can't tell if this is an error that I can be expected to > recover from as a user. > > We see this error only sometimes. Other times, we REFRESH the > subscription and it makes progress as one would expect. > > Can anyone advise on what we are doing wrong here? > > -Joe
