5.8.3 Characteristics of the methods for processing set operations
The following table shows the characteristics of each method for processing set operations.
|
Methods for processing set operations |
Benefits |
Disadvantages |
|---|---|---|
|
Hash execution |
Results can be obtained at a higher speed when the data required for the set operation can be stored in the hash table area. |
If a shortage occurs in the hash table area due to a large amount of data required for the set operation, processing performance decreases because the data is temporarily saved in a work table. |
|
Work table execution |
This method is applicable to all set operations. |
If there are a large number of retrieval results, the amount of data stored in the work table becomes large. In this case, processing performance decreases because deduplication is performed after the data stored in the work table is sorted. |