# Apache Impala Reference

> All Impala authentication options and data type handling.

#  Apache Impala Reference

Authentication options and data type handling for [Impala connections](../connect/impala.md).

## Authentication

| Variable | Example | Description |
|---|---|---|
| `DATACONTRACT_IMPALA_USERNAME` | `analytics_user` | Username |
| `DATACONTRACT_IMPALA_PASSWORD` | `mysecretpassword` | Password |
| `DATACONTRACT_IMPALA_USE_SSL` | `true` | Whether to use SSL (defaults to true) |
| `DATACONTRACT_IMPALA_AUTH_MECHANISM` | `LDAP` | Authentication mechanism (defaults to LDAP) |
| `DATACONTRACT_IMPALA_USE_HTTP_TRANSPORT` | `true` | Whether to use HTTP transport (defaults to true) |
| `DATACONTRACT_IMPALA_HTTP_PATH` | `cliservice` | HTTP path for the Impala service (defaults to cliservice) |

`host`, `port`, and `database` come from 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.