On 2018-10-31 09:15, Simon Riggs wrote:
On Wed, 31 Oct 2018 at 07:58, Erikjan Rijkers <e...@xs4all.nl> wrote:
I have also noticed that logical replication isn't possible on tables
with a generated column. That's a shame but I suppsoe that is as
expected.
Couldn't see anything like that in the patch. Presumably unintended
consequence. The generated value needs to be in WAL, so decoding it
should
be trivial.
These log messages occur on attempting at logical replication:
( table t1 has no generated columns; replicates fine.
table t2 has one generated column; replication fails: see below )
LOG: database system is ready to accept connections
LOG: logical replication apply worker for subscription "sub1" has
started
LOG: logical replication table synchronization worker for subscription
"sub1", table "t1" has started
LOG: logical replication table synchronization worker for subscription
"sub1", table "t2" has started
LOG: logical replication table synchronization worker for subscription
"sub1", table "t1" has finished
ERROR: column "i2" is a generated column
DETAIL: Generated columns cannot be used in COPY.
LOG: background worker "logical replication worker" (PID 22252) exited
with exit code 1
Virtual columns wouldn't need to be replicated.
I guess we might choose to replicate generated cols as a value, or
leave
them out and let them be generated on the downstream side. The default
should be to just treat them as a value.
--
Simon Riggs http://www.2ndQuadrant.com/
<http://www.2ndquadrant.com/>
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