系统设计

2020 03 01

什么是Radix Tree
在计算机科学中，基数树，或称Patricia trie/tree，或crit bit tree，压缩前缀树，是一种更节省空间的Trie（前缀树）。对于基数树的每个节点，如果该节点是唯一的子树的话，就和父节点合并。

 

 

2020 04 21

publisher/subscriber

Notification Service to drivers/customers

Show nearby derivers to customers, subscribe the customer for all the updates of its nearby derivers = always show drivers' current locations to customers 

1 request a ride

2 server finds nearby drivers

3 sort drivers send updates to customers

4 send request to drivers

5 driver accpets, and notifies customer

websocket: 

 

primary/secondary server

SSDs with fast IOs