数据库：流水线函数 [英] Database: Pipelined Functions

问题描述

我是管道函数的新概念。我有一些关于

的问题：从数据库的角度：

• 使用管道功能解决了什么挑战？


• 使用管道功能的优化优点是什么？

解决方案

引用fomAsk Tom Oracle：

流水线函数只是你可以假装的代码是数据库表

流水线函数给你>

select * from PLSQL_FUNCTION;

使用它 - 从函数中选择*，而不是表，它
可能是有用的。

至于优点：使用管道功能的一大优点是，您的函数可以一个接一个地返回行，而不是在返回之前将整个结果集作为一个整体在内存中构建。

上面给出了明显的优化 - 否则会返回大结果集的内存节省。

一个非常有趣的例子使用流水线函数在这里

什么似乎很好地利用了它们是ETL（提取/转换/加载） - 例如参见这里

I am new to the concept of Pipeline Functions. I have some questions regarding

From Database point of view:

• What actually is Pipeline function ?
• What is the advantage of using Pipeline Function ?
• What challenges are solved using Pipeline Function ?
• Are the any optimization advantages of using Pipeline Function ?

Thanks.

解决方案

To quote fom "Ask Tom Oracle":

pipelined functions are simply "code you can pretend is a database table"

pipelined functions give you the (amazing to me) ability to

select * from PLSQL_FUNCTION;

anytime you think you can use it -- to select * from a function, instead of a table, it might be "useful".

As far as advantages: a big advantage of using a Pipeline function is that your function can return rows one-by-one as opposed to building the entire result set in memory as a whole before returning it.

The above gives the obvious optimization - memory savings from something that would otherwise return big result set.

A fairly interesting example of using pipelined functions is here

What seems to be a good use of them is ETL (extract/transform/load) - for example see here

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