Jan 1, 0001

Local Storage ~ Storage Engine

Operations

  • Put(k, v)
  • Get(k)
  • Delete(k)
  • ScanRange(from, to)

Guarantees

  • ACID
    • Atomicity
    • Consistency
    • Isolation
    • Durability

Hardware

  • HDD
    • big and cheap
    • mechanical!
    • move arm
    • read sectors
    • 6ms for one rotation
    • do not shout at them

03-sem-hdd.png

  • SSD
    • small and expensive
    • flash memory
    • cell -> page -> block
    • garbage collection

03-sem-ssd.png

  • Require sequential reads and writes!

Impl

Keys in memory, values on disk!

Write-Ahead logging! -> Durability