> For the complete documentation index, see [llms.txt](https://liuzhenglaichn.gitbook.io/system-design/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://liuzhenglaichn.gitbook.io/system-design/todo-1/todo.md).

# TODO

* Flink: <https://flink.apache.org/>
* Kafka: <https://kafka.apache.org/>
* Zookeeper: <https://zookeeper.apache.org/>
* Lucene: <https://lucene.apache.org/>
* Earlybird: Real-Time Search at Twitter
* ElasticSearch

Cache

* Memcache
* Redis

Ranking

* PageRank

Remove Duplicate

* MinHash

Gateway

Star Schema vs. Snowflake Schema