mongodb索引数据结构 [英] mongodb index data structures

问题描述

mongodb是否区分由小的静态大小的元素（可以说数字类型）和大型变体类型（如字符串）构成的索引？

从BSON规范可以看出，BSON确实显示了整体类型的特殊处理能力。如果索引只包含int64，我希望索引代码创建更多的性能指标。

也许它有某种形式的歧视联盟？

解决方案

B-Tree内容基本上只是索引字段的BSON序列化表示，并指向该磁盘的磁盘位置对象。

这是一个链接到代码，它提到了这一点。其实这里是 woCompare 函数，它们在循环索引时使用。

看起来像一个简单的二进制比较，所以更小数据将比较大的数据比较快。

Does mongodb discriminate between indices constructed of small, statically sized elements (lets say numeric types) and those with large variant types (such as strings) ?

From the BSON spec I can see that BSON does show the capacity of special treatment of integral types. I would expect the indexing code to create more performant indices if the index contains only int64's.

Perhaps it has some form of discriminated union ?

解决方案

The B-Tree contents are basically just the BSON serialized representation of the indexed fields and a pointer to the disk location of that object.

Here is a link to the code where it mentions this. In fact, here is the woCompare function they use while looping through the index.

Looks to me like a simple binary comparison, so smaller data will compare faster than larger data.

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