115 lines
6.7 KiB
Markdown
115 lines
6.7 KiB
Markdown
---
|
|
permalink: "/{{ year }}/{{ month }}/{{ day }}/redis-dev-day-london-2015"
|
|
title: Redis Dev Day London 2015
|
|
published_date: "2015-10-22 15:05:00 +0200"
|
|
layout: post.liquid
|
|
data:
|
|
route: blog
|
|
---
|
|
Last Monday the Redis Dev Day took place in London, followed by a small Unconference on Tuesday.
|
|
The Redis Dev Day is a gathering of all people involved in the Redis development,
|
|
that means Redis creator [Salvatore][antirez] as well developers and engineers from several companies
|
|
are there to discuss the future development of Redis.
|
|
|
|
Thanks to [Rackspace][] and especially [Nikki][] I was able to attend as well.
|
|
|
|
The Dev Day itself was packed with proposals and interesting ideas about improvements and new features for Redis.
|
|
In the following I'm trying to sum up some of them, listed by their relevance as I see them (most relevant first).
|
|
|
|
## NoNoSQL for Redis
|
|
|
|
[Salvatore][antirez] itself proposed this one: Native indexing in Redis.
|
|
He recently published [an article on indexing][indexing] based on Sorted Sets.
|
|
While this method is manual, it could very well be hidden behind a nice client interface (and indeed there are some out there, I just can't find a good example).
|
|
But having it right inside Redis might be more memory-efficient, faster, avoids transactions and might be easier to use.
|
|
Salvatore proposed new commands for that, for example to select based on a previously defined index:
|
|
|
|
```
|
|
IDXSELECT myindex IFI FIELDS $3 WHERE $1 == 56 and $2 >= 10.00 AND $2 <= 30.00
|
|
```
|
|
|
|
None of this is final yet, there are a lot of things to get right before this can be implemented.
|
|
For example it's not done with providing the commands for selection based on indexes, but needing to add, update and remove the index is necessary as well.
|
|
More in-depth discussions happened the next day, prior to the Unconf.
|
|
|
|
<center>
|
|
<blockquote class="twitter-tweet" lang="en"><p lang="en" dir="ltr">Pre-Unconf Dev Meetup in progress! <a href="https://twitter.com/hashtag/RedisLondon?src=hash">#RedisLondon</a> <a href="https://t.co/7HhFocK9J0">pic.twitter.com/7HhFocK9J0</a></p>— c-&gt;flags (@badboy_) <a href="https://twitter.com/badboy_/status/656499542750269441">October 20, 2015</a></blockquote>
|
|
<script async src="//platform.twitter.com/widgets.js" charset="utf-8"></script>
|
|
</center>
|
|
|
|
Even though this kinda goes against the current idea of Redis
|
|
-- provide the basic tools with a simple API and not much more --
|
|
there is the possibility to implement it right and make it as usuable as Redis is right now.
|
|
|
|
This proposal needs more design effort to get right (both on the exposed API and internal design).
|
|
|
|
## Redis as a Cloud Native
|
|
|
|
[Bill][] -- yes, the real one -- always was a heavy user of Sentinel and thus had the most insight on what works and what doesn't.
|
|
And in fact one big thing where Redis still does not work in a way that anyone can be satisfied with is inside a Docker container.
|
|
Because of how Sentinel (or Cluster) announce themselves (or monitored instances) and the way Docker remaps ports,
|
|
it is currently hardly possible to run it inside a container without unusual configuration (like `--net=host`).
|
|
|
|
This needs improvements like making it possible to specify the announce address and port for all running modes.
|
|
Another thing that should be doable is configuration replication across nodes in a pod or Cluster.
|
|
This could easily be handled by a new command.
|
|
Instead of replicating all configuration automatically, this needs to be triggered by an admin, making it easy to only selectively replicate configuration options.
|
|
|
|
Both things seem necessary and not too hard.
|
|
|
|
Other proposals include:
|
|
|
|
* Save metadata inside Redis: Additional keyspace, but only exposed through special commands.
|
|
* I get why this might be wanted by big providers, personally I don't have a use case for it currently.
|
|
* Config/Persistence stored in the cloud (Persistence on AWS, Config in etcd/consul/...)
|
|
* Seems like a lot to add. I'm not convinced this belongs into the Redis core
|
|
* Redis for Memory as a Service: `malloc`, but in the cloud
|
|
* Not sure what would be necessary. `SET`/`GET` and `GETRANGE` already provide a lot. Why not implement this client-side?
|
|
|
|
## Scripting
|
|
|
|
Since the introduction of Lua scripting inside Redis more and more people use it as a way to abstract logic away behind a single (atomic) call.
|
|
Just look at [what is possible implementing Quadtrees inside Lua in Redis][lua-quadtree].
|
|
|
|
Because of a [security issue](http://benmmurphy.github.io/blog/2015/06/04/redis-eval-lua-sandbox-escape/) access to the debug feature in Redis was disabled.
|
|
This also breaks some of the available options to properly debug Lua scripts.
|
|
Debug functionality is needed once you go this route, so bringing it back eventually is a good idea and maybe [finally closing very old issues](https://github.com/antirez/redis/pull/732).
|
|
|
|
## Command composition
|
|
|
|
For some commands we have `STORE` options ([`SORT`](http://redis.io/commands/sort) has it as an option, [`SINTERSTORE`](http://redis.io/commands/sinterstore) and others are their own command).
|
|
|
|
A more general form like `STORE dest SINTER keyA keyB` could make some users happy.
|
|
The current code base doesn't support that in a generic way, but it's not impossible to change that.
|
|
This might need a bit more design effort to be applied to all data types though.
|
|
|
|
## Modularity
|
|
|
|
Every time Redis gets discussed the issue about modularity comes up.
|
|
Most of the time I am a fan of making components reusable, modularize them where possible and abstract away the hard stuff.
|
|
|
|
Redis is different here.
|
|
A lot of the stuff in Redis interacts with each other and there is hardly a clear cut to make.
|
|
|
|
Should all underlying data type implementations be extracted?
|
|
They are useful for sure elsewhere, but then they won't benefit from shortcuts made.
|
|
|
|
Should the IO be completely separated from parsing and dispatching the commands?
|
|
Sounds useful for sure, especially now that the base is used in Disque as well.
|
|
But again, the coupling allows for some shortcuts.
|
|
|
|
Should hiredis be integrated and be part of the project? No way, hiredis is also a stand-alone client used by many others.
|
|
Keeping it in-tree would make it harder to develop on its on.
|
|
|
|
One thing we will do for sure is to unify the code base again.
|
|
The in-tree hiredis is currently not the same as the stand-alone one, partly due to the updated sds (the string implementation)
|
|
and partly because some bugs where fixed in the stand-alone project that don't affect Redis (I hope so)
|
|
|
|
[redislabs]: https://redislabs.com/
|
|
[rackspace]: http://www.rackspace.com/
|
|
[nikki]: https://twitter.com/nikkitirado
|
|
[antirez]: http://twitter.com/antirez
|
|
[indexing]: http://redis.io/topics/indexes
|
|
[bill]: http://twitter.com/ucntcme
|
|
[lua-quadtree]: https://gist.github.com/itamarhaber/c1ffda42d86b314ea701
|