I appreciate that this isn't a new thing here, but the handling of errors during setup is a bit off. For instance, if we fail to init the client for whatever reason, we swallow the exception and so continue trying to execute the prepared statement. 
Also, because we set initialized=true regardless, next time around we'll attempt & fail the query again. 

The alternatives would seem to be either retry the initialization each time we try to append (which would be pointless if the failure is down to a misconfiguration), or to simply log the first failure then make further append calls no-op if initializationFailed=true.

wdyt?