In Teradata Vantage, the Teradata® QueryGrid™ fabric is configured for internal communication. Two Teradata QueryGrid links are created to facilitate communication between Teradata SQL Engine and Teradata Machine Learning Engine.
QueryGrid™ Manager shows the properties that you can configure. Teradata Vantage requires that some property defaults cannot be changed.
The ML Engine connector properties are:
| Name | Default | Description | Connector Type | Change Default |
|---|---|---|---|---|
| Server | Configured specifically to your environment | Hostname of ML Engine server. | Target | No |
| Port | 30002 | Port number of ML Engine server. | Target | No |
| Authentication Mechanism | Trusted | Authentication mechanism used to log on to ML Engine. | Target | No |
| Realm | None | Realm name for Kerberos. | Target | No |
| Servicename | None | Service name for Kerberos. | Target | No |
| Database Name | beehive | Database name for ML Engine. | Target | No |
| Schema Name | none | Default schema name. | Target | Yes |
| Link Buffer Count | 4 | Maximum number of write buffers available on a single channel at one time. | Initiator, Target | Yes |
| Link Buffer Size | 1048576 | Maximum size of the write buffers to allocate for row handling and message exchange. | Initiator | Yes |
| Link Heartbeat Interval | 60000 | Maximum interval in milliseconds for heartbeat signal on channel between connector and fabric instance, used for health check status. This interval must be greater than Link Handshake Timeout. | Initiator, Target | Yes |
| Link Handshake Timeout | 30000 | Handshake timeout in milliseconds for link channel setup. | Initiator, Target | Yes |
| Read Timeout | 30000 | Number of milliseconds to wait to read between data packets when importing data messages. | Initiator, Target | Yes |
| Write Timeout | 30000 | Number of milliseconds to wait to write between data packets when exporting data messages. | Initiator, Target | Yes |
| Response Timeout | 1800000 | Number of milliseconds to wait for final data exec response when all data has been transferred. | Initiator, Target | Yes |
| Enable Logging | WARN | Logging level for connector or link properties. Applies to both initiating and target connector; however, if their levels are different, level for initiating connector takes precedence. | Initiator, Target | Yes |
| Default String Size | 32000 | VARCHAR truncation size (size at which data imported from, or exported to, string columns is truncated). Value represents maximum number of Unicode characters to import. | Initiator, Target | Yes |
| Transformformatting | FALSE | Whether to transform array columns to Teradata string format. If FALSE, array columns are returned in JSON format, except those specified in RETURN clause to be returned in Teradata string format. | Initiator, Target | Yes |
| User Name | beehive | Value to use when initiator does not support mechanism to provide user credentials. Value is also used for connectivity diagnostic checks. | Target | No |
| Password | Password for User Name. | Target | Yes | |
| Enable Clob Support | TRUE | Enables support of CLOB datatype. | Initiator, Target | Yes |
| Enable Blob Support | FALSE | Enables support of BLOB datatype. | Initiator, Target | No |
| Large Clob Handling | ERROR | Action to take if CLOB larger than 10485760 is exported to ML Engine: ERROR causes exception to be raised; TRUNCATE causes data to be truncated to 10485760. To change this behavior in SQL Engine session, include statement such as: set foreign server attr = 'servername=coprocessor;largeClobHandling=TRUNCATE;' for session volatile; |
Initiator, Target | Yes |
| Large Blob Handling | ERROR | Action to take if BLOB larger than 10485760 is exported to ML Engine: ERROR causes exception to be raised; TRUNCATE causes data to be truncated to 10485760. To change this behavior in SQL Engine session, include statement such as: set foreign server attr = 'servername=coprocessor;largeBlobHandling=TRUNCATE;' for session volatile; |
Yes | |
| In-Memory Tables | TRUE | Whether to use in-memory tables for data exported to Teradata SQL Engine for input to functions. | Target | Yes |
| Connection Max Idle Time | 1800 seconds | Maximum idle time for connection cache object, after which it is closed and evicted from the cache. It should be used if there are multiple concurrent users/queries running on the system that might lead to starvation of connection objects. | Target | Yes |
| Connection Pool Size | 100 | Maximum number of connection objects that can be stored in the connection pool. When trying to acquire a new connection, the connector checks for entry to be made available in the connection pool or else it fails after 5 minutes. There is one connection pool per connector config, including the username. This can be used to throttle the number of connections that can be established by concurrent queries for one user. | Target | Yes |
| Connection Evict Frequency | 1 minute | Frequency of eviction checks. It checks, closes, and removes the connection object from the pool if the idle time (current time - last time of use) of connection object is greater than connectionMaxIdleTime/sessionConnectionMaxIdleTime. It can be reduced if there are multiple concurrent users running queries and due to high demand, the connections should be freed up more frequently for new users to pick up. | Target | Yes |