## Antirez

- NoNoSQL - IDXSELECT for indices
  - based on sorted sets
  - but sorted sets have unique elements only
  - `IDXSELECT myindex IFI FIELDS $3 WHERE $1 == 56 and $2 >= 10.00 AND $2 <= 30.00`
- Timeseries database
  - not possible to built upon sorted sets
  - new data structure, API
- Multiple AOF file to avoid in-memory buffer on AOF rewrite
- RDB-prefixed AOF to save space
- Redis-CP
  - Redis with proxy in front for proper Raft/consensus

## Redis as a Cloud native (Bill)

- Delayed Availability
  - Start up, read RDB, set everything up
  - but wait with serving clients to have the possibility to change config beforehand
- Config Replication / Sync
  - Sync configuration changes to slave instances
  - Only some configurations should be synced, opt-out for SAVE or similar
- Metadata for Instances
  - Setable via API, add administrative tags
  - Limit to a few key-value pairs (~100)
  - Persist it into the config file
- Sentinel
  - Sync sentinel options to other Sentinel nodes
  - Issue: 3 hosts with 1x Sentinel, 1x Redis
    - kill host with master → failover fails
  - Issue: Sentinel remove data lag
    - Sentinel Config state is reapplied after removing, then re-adding quickly
    - Some epoch/config changes still in flight to Sentinel node
  - Goodbye message on Sentinel removes
    - Lower seen Sentinel nodes
  - Slave remove
    - Forget this slave, don’t re-discover it
  - Let Sentinel distribute removals instead of user
    - make it blocking until it has ACKs from all other
- Config stored in the cloud 
  - backing store (etcd, consul, …) or cloud storage (AWS, …)
  - Abstract used store, e.g. similar to https://github.com/docker/libkv
  - Sync back and forth between Redis and stored config
  - antirez: Redis-CP might cover a few things already
- Redis - Memory as a Service
  - Have a malloc-on-redis
  - Fixed-size data entries
  - fixed-size counters in contiguous memory
    - Possible: get substring (`GETRANGE`)
    - Next: Increment sub-part of value

## Redis in Docker

- use `--net=host`: Use host network directly, no ip/port remapping
- Everything in Docker except Redis
  - Redis is foundation
  - Docker is immutable infrastructure

## Microservices in Redis (Mario)
- IP-AS Lookup using Redis, Lua scripts and some logic in the scripts
- `MONITOR`: Include Lua script handle
- Aliases for Lua scripts

## Itamar
- Quadtrees in Lua in Redis for 2-dimensional range queries
  - https://gist.github.com/itamarhaber/c1ffda42d86b314ea701
  - https://en.wikipedia.org/wiki/Quadtree
  - Geohashes are basically a flattened Quadtree, maybe usable for 2-dim queries
- We need more sophisticated APIs for queries
- Lua Debugging
  - http://www.trikoder.net/blog/foo-89
  - https://github.com/slembcke/debugger.lua
- Lua PRs
  - antirez/redis#732 

## Redis Source Modularity
- libredis
  - RDB parsing
  - Protocol parsing
  - Command table
  - Generic Redis protocol server
- tension between performance and more abstraction/modularity
  - coupling avoids indirections, fast paths
  - organisation of dependencies, circular dependencies: hiredis → sds → redis → sds

## Master ←→ Master Replication (Yftach, Redis Labs)

- No conflict resolution
- Introduce proxy master in between two Clusters
  - Gets writes from all masters, resolves conflicts and sends back fix commands

## From a Client perspective

- Command composition
  - `STORE dest SINTER keyA keyB`