pentaho - Pentaho Kettle (PDI) table input step with field substitution running slower than using literal

Question

I'll go straight to the point. I have a table input step, which reads records with a query that includes a where clause, as follows:

SELECT * id, name, surname, creation_date
FROM users
WHERE creation_date > ?

If a put a literal (i.e. '2017-04-02T00:00:00.000Z') in palce of the question mark, this step reads all new values, which could be thousands, in millis. If I use the field substitution and use the incoming value, it takes minutes.

Do you know why this could be happening? Do you know how to solve the issue?

Thank you very much for your time.

Answer 1

我找到了一种解决方法，不是针对此特定问题的解决方案，但它有效：代替从上一步获取值并使用字段替换（查询中的？），我在作业中读取先前转换中的值，将其存储在变量空间中，并使用变量替换（查询中的'${variable_name}'）从那里读取它，它的工作速度与硬编码值一样快。