In theory this should just be error messages and not partial query data, but I don't completely understand the network state machine. This is mostly to make sure we flush error messages on connection startup. See PostgresProtocolInterpreter::ProcessStartup's error states.
This came from @lmwnshn seeing behavior where clients couldn't connect while a simultaneous transaction was running that made DDL changes. We now get the verbose error (that was always written to the packet, just never flushed) returned to the client.
Client 1:
$ psql -h localhost -p 15721 -d noisepage
psql (12.7 (Ubuntu 12.7-0ubuntu0.20.04.1), server 9.5devel)
Type "help" for help.
noisepage=# begin;
BEGIN
Time: 1.427 ms
noisepage=# create table foo (id int);
CREATE TABLE
Time: 7.825 ms
noisepage=#
Client 2:
$ psql -h localhost -p 15721 -d noisepage
psql: error: FATAL: Failed to create a temporary namespace for this connection. There may be a concurrent DDL change. Please retry.
In theory this should just be error messages and not partial query data, but I don't completely understand the network state machine. This is mostly to make sure we flush error messages on connection startup. See
PostgresProtocolInterpreter::ProcessStartup's error states.This came from @lmwnshn seeing behavior where clients couldn't connect while a simultaneous transaction was running that made DDL changes. We now get the verbose error (that was always written to the packet, just never flushed) returned to the client.
Client 1:
Client 2: