A transaction is a single logical operation on the data. Impala supports transactions that satisfy a level of consistency that improves the integrity and reliability of the data before and after a transaction.
Specifically, Impala provides atomicity and isolation of insert operations on transactional tables. A single table insert is either committed in full or not committed, and the results of the insert operation are not visible to other query operations until the operation is committed.
For single table, the inserts are ordered, so if Impala doesn't see a committed insert, it won't see any insert committed after it.
For insert-only transactional tables, you can perform the following statements:
CREATE TABLE, DROP TABLE, TRUNCATE,
INSERT, SELECT
All transactions in Impala automatically commit at the end of the statement. Currently, Impala does not support multi-statement transactions.
Insert-only tables must be the managed and file-format based tables, such as Parquet, Avro, and text.