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Function calls in SQL – Black Box for the Optimizer?

May 25 @ 12:00 - 13:00

Function calls in SQL - Black Box for the Optimizer?

Functions in SQL are a useful and popular feature that is often used. However, little attention is often paid to performance aspects. A function call or an expression in a WHERE condition is a challenge for the query optimizer that often leads to unsuitable execution plans and bad response times. For PL/SQL functions called from SQL, the situation is even more complex. If used incorrectly, they can lead to massive performance degradation.
In this presentation, I will show different possibilities to support the optimizer in function calls to generate better execution plans. Furthermore, I will explain how PL/SQL functions can be used optimally in SQL queries and which performance killers must be avoided. Of course, all this will be demonstrated with live examples and stories from the field.