I have created the following table:
create external table dev.impala_precision_test(
row format delimited fields terminated by '|'
on a text file with these 2 rows of data:
The first number has 20 significant decimal digits, the second one 19.
This is the result retrieved by Impala (impala-shell), where the first number is incorrectly represented:
This is instead the result from Hive (Beeline shell), where both numbers are correctly rounded-off:
Also float data type, in Impala, seem suffer from the same problem.