1 Hash Table Index + Append Log
advantages
- Perform > Random Write
- Concurrent + Crash / recovery
disadvantages
- memory
- range query
2 SSTable. (Sorted String Table). LSMtable
advantages
- sorted. (Binary search)
- key-- segment. Merge Sort
- data structure. Red Black Tree (Mem - table)
- compact. (Write. Read)
disadvantages
lost update (memory)
3 B tree B+Tree
B Tree
K-V index
secondary index
branch factory
Block - Page
4 layers. 4kb 1 ref.
change one ref. need to modify 3 parts. (the parent, two children)