![](https://i.imgur.com/WyNK1V8.png)
![](https://i.imgur.com/BBhMxQu.png)
![](https://i.imgur.com/kYsncFc.png)
- Cassandra was a blend of distributed features of Dynamo and Data Model of BigTable
![](https://i.imgur.com/jLWMXAI.png)
- Shared nothing, add, remove as needed
![](https://i.imgur.com/09SSAgz.png)
- Data written to commit log
![](https://i.imgur.com/ZTyUcOO.png)
![](https://i.imgur.com/D5N3lOM.png)
- Server acknowledges to client
![](https://i.imgur.com/xQV2yoT.png)
- Memtable flushed to disk
- to SSTable
- In Sequential Write
- Really good for time-series
![](https://i.imgur.com/xRxBm0g.png)
- How to Deal with duplicates?
![](https://i.imgur.com/IHsjmAp.png)
- Compaction of Sequential Append only SSTables
![](https://i.imgur.com/Xpya6Xx.png)
![](https://i.imgur.com/ujehy0Y.png)
![](https://i.imgur.com/dex0WMq.png)
![](https://i.imgur.com/KyaFGgA.png)
- Partitioning wiht primary key
![](https://i.imgur.com/TYY0pCr.png)
![](https://i.imgur.com/MHygD5U.png)
![](https://i.imgur.com/2BSAzj9.png)
![](https://i.imgur.com/zX2rOTP.png)
![](https://i.imgur.com/5R83ip3.png)
![](https://i.imgur.com/0dVXJGi.png)
![](https://i.imgur.com/jA0Gqpm.png)
![](https://i.imgur.com/W3Fk6J6.png)
- Consistency Level
- Quorum is when more than 51% replicas acknowledge data read
- ALL - All replicas ack - full consistency - usually not necessary
![](https://i.imgur.com/LcQBXYS.png)
![](https://i.imgur.com/sQQnSvq.png)
![](https://i.imgur.com/jc7GfAZ.png)
- CQL Cassandra Query Language
![](https://i.imgur.com/NggTITR.png)
- Inserts will always overwrite
![](https://i.imgur.com/de8OuRD.png)
![](https://i.imgur.com/s04wsEr.png)