Impala planner will check whether an ident needs to be quoted in toSql outputs by using the HiveLexer (org.apache.hadoop.hive.ql.parse.HiveLexer). However, when there are parse errors from HiveLexer, the error messages will be printed to stderr which is redirected to impalad.ERROR. Actually, these error messages only means the ident needs to be quoted. They should have a lower log level and shouldn't be printed to impalad.ERROR.
A possible solution is to extend HiveLexer and override the displayRecognitionError() as HiveLexerX does. We can also consider using HiveLexerX directly.
Some error messages are printed in impalad.ERROR: