- AMP level only. The per-AMP space quota is the maximum permissible AMP-level space. This is the default.
- Global level, which maintains both an overall system limit and AMP limits. This strategy can provide extra space to AMPs when needed by temporarily reducing space for AMPs that do not need the space now.
When DBAs manage space at the AMP level, transactions or long-running load jobs end abnormally when space use exceeds hard limits set for the database or user. If a DBA manages space at the global level, two allowances can be made to increase space to AMPs when needed:
| Space Allowance | Creation Method | Description |
|---|---|---|
| Skew factor | The SKEW option in a CREATE USER/DATABASE or MODIFY USER/DATABASE request. | Gives extra space to one or more AMPs when needed, up to the value of the SKEW option. The skew option can be defined as a percentage or a constant expression. You can apply this option to PERM, SPOOL, and TEMP space. A skew limit value of 0 means that the AMP space quota is the space limit, and Vantage does not provide more space to AMPs, even when other AMPs have space available. A non-zero soft limit percent permits this quota to increase by the soft limit percent. Users get an error if actual space use exceeds the soft limit. The default value for the default skew limit percent fields is 0. The DBC.GlobalDBSpace table records the cumulative allocations of the AMPs and maintains database and user global-level space limits. |
| Global soft limit | Set a non-zero value. | The percentage by which a database or user is allowed to exceed the maximum space limit. This setting applies to PERM, SPOOL, or TEMP space. The default value is 0. The system sends alerts when processing exceeds soft limits, so the DBA can take corrective action. Processes that cannot be stopped (such as transaction recovery) may be in progress when the soft limit is exceeded or when physical storage limits are close. The system continues processing but reports alerts with higher severity levels. The DBA is expected to increase affected space in this situation. |