Apama 10.15.0 | Developing Apama Applications | Developing Apama Applications in EPL | Working with Streams and Stream Queries | Troubleshooting and stream query coding guidelines | Prefer equi-joins to cross-joins
 
Prefer equi-joins to cross-joins
In a query using an equi-join, the items from the two input sets are joined based on equality of key values. The identification of matching items is very efficient.
Cross-joins have no expressions, so it is more efficient to calculate them than equi-joins. However, cross-joins are less preferable to equi-joins if they produce unwanted items that must subsequently be filtered out.