# Gache notions

## Basic idea

Like Memcached, plus...

* Usability:
  * True FLUSHALL equivalent to an instance restart
  * Single process for multiple bins
* Management
  * Complete locking dump/restore (compare cachedump` / `lru_crawler metadump all`)
  * Snapshots
* Tag support
* Pluggable storage
  * Journaling
  * Write-back/write-through replication
  * Chained storage (fast → slow)

Likely to be slower overall, but more convenient.

## Components

### Server

* Runner
  * POSIX-style [options](runner_cli.md), not native in Go
  * [Configuration loading](runner_config.md) for systemd (and others) integration
* Protocol handling (FSMs)
  * Application: Memcache protocol proper
  * Presentation: ASCII / Binary
  * Transport "connection":
    * TCP with persistent connections
    * TCP without persistent connections
    * UDP
    * raw socketpair (stdin/stdout)
  * [Event handling](event_handling.md)
* [Readline equivalence](readline.md) for ASCII presentation interactions
* Storage
  * [Hash logic](hash.md) for keys
  * Pluggable storage
    * Journaling
  * Storage engines
    * [Memory](storage_memory.md)
    * Memcached, for use as a debugging proxy in front of a standard instance
    * Others ?
  * Memory
      * Main memory allocation
      * Slab allocator
  * Reporting
  * Background expiration lurker (cf standard `lru_crawler`)

### Client library

### Testing tools

* memslap, from libmemcached
  * On MBP2016, memcached 1.5.0 makes 25kqps on the set test,