On Mon, May 11, 2020 at 2:41 AM Euler Taveira <euler.taveira@2ndquadrant.com> wrote: > > Hi, > > While looking at an old wal2json issue, I stumbled on a scenario that a table > with a deferred primary key is not updatable in logical replication. AFAICS it > has been like that since the beginning of logical decoding and seems to be an > oversight while designing logical decoding. >
I am not sure if it is an oversight because we document that the index must be non-deferrable, see "USING INDEX records the old values of the columns covered by the named index, which must be unique, not partial, not deferrable, and include only columns marked NOT NULL." in docs [1].
Inspecting this patch again, I forgot to consider that RelationGetIndexList() is called by other backend modules. Since logical decoding deals with finished transactions, it is ok to use a deferrable primary key. However, this patch is probably wrong because it does not consider the other modules.
