Teradata Database dynamically allocates available permanent space as spool space when necessary. To make sure that reducing permanent space does not impact transaction processing, Teradata recommends that you reserve permanent space for spool requirements.
At minimum, the average uncompressed and non-fallback protected database should reserve 40% of space relative to CURRENTPERM. (For example, if CURRENTPERM is 100 GB, spool space will be 40 GB for a total MAXPERM of 140 GB.)
You may increase the reserve as needed depending on your actual workload. Use the following table to help you estimate your spool space requirements. Note that the percent of spool space suggested is relative to CURRENTPERM.
| System Fallback Rate | Compression Rate | Spool Space Reserve Recommended (Percent Relative to CURRENTPERM) |
|---|---|---|
| 100% | 0% | 20% |
| 100% | 40% | 30% |
| 50% | 20% | 32% |
| 0% | 0% | 40% |
| 0% | 40% | 60% |
Because every site is different and can greatly vary, use these numbers as guidelines only.