Hi I met a problem in synchronous logical replication. The client hangs when TRUNCATE TABLE at publisher.
Example of the procedure: ------publisher------ create table test (a int primary key); create publication pub for table test; ------subscriber------ create table test (a int primary key); create subscription sub connection 'dbname=postgres' publication pub; Then, set synchronous_standby_names = 'sub’ on publisher, and reload publisher. ------publisher------ truncate test; Then the client of publisher will wait for a long time. A moment later, the publisher and subscriber will report following errors. Subscriber log 2021-04-07 12:13:07.700 CST [3542235] logical replication worker ERROR: terminating logical replication worker due to timeout 2021-04-07 12:13:07.722 CST [3542217] postmaster LOG: background worker "logical replication worker" (PID 3542235) exited with exit code 1 2021-04-07 12:13:07.723 CST [3542357] logical replication worker LOG: logical replication apply worker for subscription "sub" has started 2021-04-07 12:13:07.745 CST [3542357] logical replication worker ERROR: could not start WAL streaming: ERROR: replication slot "sub" is active for PID 3542236 Publisher log 2021-04-07 12:13:07.745 CST [3542358] walsender ERROR: replication slot "sub" is active for PID 3542236 2021-04-07 12:13:07.745 CST [3542358] walsender STATEMENT: START_REPLICATION SLOT "sub" LOGICAL 0/169ECE8 (proto_version '2', publication_names '"pub"') I checked the PG-DOC, found it says that “Replication of TRUNCATE commands is supported”[1], so maybe TRUNCATE is not supported in synchronous logical replication? If my understanding is right, maybe PG-DOC can be modified like this. Any thought? Replication of TRUNCATE commands is supported -> Replication of TRUNCATE commands is supported in asynchronous mode [1]https://www.postgresql.org/docs/devel/logical-replication-restrictions.html Regards, Tang
