MongoDB

Coded in C++.

1 相关术语

  1. 数据库/database: 一个MongoDB中可以建立多个数据库。MongoDB的单个实例可以容纳多个独立的数据库，每一个都有自己的集合和权限，不同的数据库也放置在不同的文件中。
  2. 集合/Collection:集合就是 MongoDB 文档组，类似于 RDBMS （关系数据库管理系统：Relational Database Management System)中的表格。集合存在于数据库中，集合没有固定的结构，这意味着你在对集合可以插入不同格式和类型的数据，但通常情况下我们插入集合的数据都会有一定的关联性。
  3. 文档/Document: 文档是一组键值(key-value)对(即BSON)。MongoDB 的文档不需要设置相同的字段，并且相同的字段不需要相同的数据类型，这与关系型数据库有很大的区别，也是MongoDB 非常突出的特点.In theory, each document in a collection can have a completely different structure; in practice, a collection’s document will be relatively uniform.
  4. Ad hoc queries（即席查询）:是用户根据自己的需求，灵活的选择查询条件，系统能够根据用户的选择生成相应的统计报表。即席查询与普通应用查询最大的不同是普通的应用查询是定制开发的，而即席查询是由用户自定义查询条件的。
  5. B-Tree Index/LSM(log-structured merge-trees)/Geospatial索引/复合索引(compound index)/唯一索引/稀疏索引
  6. beefier CPU: 功能更强大的CPU
  7. Capped Collections/固定集合 : 是性能出色且有着固定大小的集合，对于大小固定，我们可以想象其就像一个环形队列，当集合空间用完后，再插入的元素就会覆盖最初始的头部的元素！
  8. Aggregation Framework/聚合框架: 它是数据聚合的一个新框架，其概念类似于数据处理的管道。 每个文档通过一个由多个节点组成的管道，每个节点有自己特殊的功能（分组、过滤等），文档经过管道处理后，最后输出相应的结果。
  9. One-of-a-kind item : 独一无二的产品
  10. hedge inventory 囤积库存 ; 避险库存
  11. You can always discover total index size by looking at the results of the stats command. The working set is the subset of total data commonly queried and updated, which is different for every application.
  12. Ratio of RAM-to-working set size
  13. 客户端管理工具:Robomongo/NoSQLBooster for MongoDB/Studio 3T
  14. the ability to scale easily with automatic failover --- 通过自动故障转移轻松扩展的能力
  15. On-Demand Materialized Views : 随需应变物化视图 /on-premises hardware
  16. A replica set is a group of MongoDB servers that maintain the same data set, providing redundancy and increasing data availability.
  17. MongoDB write concern : MongoDB写入策略，写入关注。写入策略是指当客户端发起写入请求后，数据库什么时候给应答，mongodb 有三种处理策略：客户端发出去的时候，服务器收到请求的时候，服务器写入磁盘的时候
  18. you might consider “rolling-up” the small documents into larger documents that contain an array of embedded documents. (您可能会考虑将小型文档“汇总”为包含嵌入式文档数组的较大文档。)
  19. tighter index bounds (更严格的索引范围)
  20. Web Page Search Engine --- Google / full-featured text search engine(全功能文本搜索引擎 dedicated text search engine--Amazon) / MongoDB Text Search
  21. faceted search : 多面搜索/方面搜索
  22. backups are there in case of a logical failure such as an accidental data loss or data corruption <如果发生逻辑故障（例如意外数据丢失或数据损坏），则有备份>
  23. When designing a compound MongoDB index:
    1. Keys for equality filters should appear first
    2. Keys used for sorting should appear before multivalue fields
    3. Keys for multivalue filters should appear last
  24. How MongoDB guarantees durability at the replica set member level through journaling <MongoDB如何通过日记保证副本集成员级别的持久性>
  25. Like most databases, MongoDB maintains in-memory views of both the journal and the database data files. By default, it flushes journal entries to disk every 50 milliseconds and flushes database files to disk every 60 seconds. The 60-second interval for flushing data files is called a checkpoint. The journal is used to provide durability for data written since the last checkpoint. With respect to durability concerns, if the server suddenly stops, when it's restarted the journal can be used to replay any writes that were not flushed to disk before the shutdown.
  26. MongoDB's mapped memory includes all of the data MongoDB has ever accessed (all the pages of data it has addresses for). It will usually be about the size of your dataset.

References

  1. MongoDB Package Components References
  2. Understanding Journaling in MongoDB
  3. How MongoDB's Journaling Works
  4. MongoDB新存储引擎WiredTiger实现(事务篇)
  5. 14 Things I Wish I’d Known When Starting with MongoDB
  6. MongoDB Go Driver

  7. mongodb/mongodb-enterprise-kubernetes

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