TODO.md

Requirements

• Mantain an in-memory list of all keys and his asociated pointer to the data on disk
• Use a single file as the database
• Work as an append only for fast writes
• Create a size reducer mecanism to mantain a sane file size when severals inserts are made
• Create a synchronization mecanism so only one operation per key is allowed

Maybe

• Create a mecanism to know if the file is corrupted (something like having a hash)

file specification

Assume binary protocol is always little endian

parts

1. Fixed size (4KB?). Contains the database metadata and/or configuration.
2. Dynamic size. Contains the key-value pair.
   • 8 byte for the size of the key
   • Key bytes
   • 1 byte that say if the key-value is active. <- the ptr is here
   • 8 byte for the size of the value
   • Value bytes

reducer mecanism

• save pointer to end of file (EOF_PTR)
• create a copy on a temp file
• on parallel reduce the temp file and create an in-memory key-ptr data structure
• stop operations
• append to temp all data that is after the EOF_PTR on the actual file
• replace the actual file with the temp file
• replace the actual in-memory key-ptr data structure with the newly created one
• restart operations

reducer scheduler

• garbage collector like strategy.