In IBM PureData System for Analytics, each disk is roughly equally divided into 3 partitions:
1. The first partition holds the primary copy of one dataslice
2. The second partition holds a mirror copy of a dataslice from a different disk.
3. The temp partition is used to store data that is generated during query execution. Temporary tables, intermediary results, etc.
• When we use temporary tables, it is this third partition, the temp space, that we risk filling up.
• It is important to only create the minimum number of temporary tables needed at a time. It is also important to only make the temporary tables as large as needed.
• Temporary tables are local to a session rather than a specific query. This means that the table may be used repeatedly within a user session. That is the major difference between Temporary tables (multiple use) and derived tables (single use). A Temporary table is materialized in swap space. However, it is not discarded until the session ends or when the user manually drops it.
![](https://www.iexpertify.com/wp-content/uploads/2020/12/Netezza-Failover.png)
When explicitly creating large temporary tables used in JOINs it is recommended to GENERATE STATISTICS on the temporary table.