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Apache Impala Reference

Authentication options and data type handling for Impala connections.

Server​

servers:
  - server: production
    type: impala
    host: my-impala-host
    port: 21050 # 443 for a Cloudera Virtual Warehouse
    database: my_database # optional default database

Authentication​

VariableExampleDescription
DATACONTRACT_IMPALA_USERNAMEanalytics_userUsername
DATACONTRACT_IMPALA_PASSWORDmysecretpasswordPassword
DATACONTRACT_IMPALA_USE_SSLtrueWhether to use SSL. Defaults to true
DATACONTRACT_IMPALA_AUTH_MECHANISMLDAPNOSASL (default), PLAIN, GSSAPI, or LDAP
DATACONTRACT_IMPALA_USE_HTTP_TRANSPORTtrueWhether to use HTTP transport instead of binary thrift. Defaults to false
DATACONTRACT_IMPALA_HTTP_PATHcliserviceHTTP path for the Impala service. Defaults to empty

Apart from use_ssl, these default to the same values as the underlying impyla driver.

host, port, and database come from the contract's servers block, and can be overridden with DATACONTRACT_IMPALA_HOST, DATACONTRACT_IMPALA_PORT, and DATACONTRACT_IMPALA_DATABASE. port defaults to 21050, Impala's binary thrift port.

Cloudera Virtual Warehouse​

A Cloudera Virtual Warehouse terminates LDAP over HTTPS on port 443, so all three transport options need setting — otherwise the client speaks binary thrift to an HTTPS endpoint and the handshake fails with TSocket read 0 bytes:

# .env
DATACONTRACT_IMPALA_USERNAME=analytics_user
DATACONTRACT_IMPALA_PASSWORD=mysecretpassword
DATACONTRACT_IMPALA_AUTH_MECHANISM=LDAP
DATACONTRACT_IMPALA_USE_HTTP_TRANSPORT=true
DATACONTRACT_IMPALA_HTTP_PATH=cliservice

with port: 443 in the contract's servers block.

Data types​

Importing​

There is no direct Impala importer. Import a SHOW CREATE TABLE DDL with datacontract import sql --dialect spark (Impala DDL is Hive-compatible): STRING/VARCHAR/CHAR → string, INT/BIGINT/SMALLINT/TINYINT → integer, FLOAT/DOUBLE/DECIMAL → number, BOOLEAN → boolean, DATE → date, TIMESTAMP → timestamp, ARRAY<...> → array, STRUCT<...> → object, BINARY → string (format binary), MAP<...> → no logical type.

Testing​

Impala does not support native type introspection — the declared physicalType is not compared against the catalog. Instead, the logicalType is checked by category (Check that field x has type y): the actual column type is normalized to one of the nine ODCS categories and compared, with integer and number treated as compatible.