The query band is a set of user-defined name-value pairs used to uniquely identify a session or transaction in the Teradata Database. Uses of the query band to tag a session or transaction include the following:
- Grouping requests into arbitrary jobs for accounting and control purposes
- Asserting a proxy user or proxy role for a trusted session
- Debugging performance problems
- Defining system variables
If you define a query band for a job, Data Mover uses that definition for all transactions on the source and target systems for the job.
Examples of the query band definition:
| If query band definition is | Because it |
|---|---|
|
valid |
follows syntactical rules: Job=payroll;Userid=aa1000000;Jobsession=1122; |
|
invalid |
uses the = character in the name: Job=payroll;User=id=aa1000000;Jobsession=1122; |
The following query band names and values should not be used.
| Name | Value |
|---|---|
| UtilityName | ARC |
| UtilityDataSize | CSPLOAD |
| BlockCompression | FASTEXP |
| TVSTemperature | FASTLOAD |
| ProxyRole | JDBCE |
| ProxyUser | JDBCL |
| MULTLOAD | |
| TPTEXP | |
| TPTLOAD | |
| TPTUPD |
The table below lists what happens in certain scenarios.
| Scenario | Description |
|---|---|
The query band contains
|
Returns an error |
| The query band exceeds 2048 characters, not counting white space padding | Returns an error |
| The query band definition repeats a name in a name-value pair | Returns an error |
| A name-value pair does not end with a ; | Returns an error |
| The name is more than 128 characters | Returns an error |
| The value is more than 256 characters | Returns an error |
| The value is 0 characters | Allows the query band definition, but does not pass a value for the associated name |