README.md

RediSQL

RediSQL is a module for Redis that embed a completely functional SQLite database.

RediSQL enables new paradigm where is possible to have several smaller decentralized databases instead of a single giant one.

With great powers comes great responsability (cit. Uncle Ben)

Documentation

This readme will provide you with the basics, however for deeper documentation you should look here: redbeardlab.tech/rediSQL/

Motivation

I love the agility provided by Redis, however, several times, I wished I had a little more structure in my in-memory database.

Even basic SQL is very powerful and years upon years of experience on several SQL implementations have brought us a very mature product that we can now exploit with confidence.

Between all the SQL implementation, the one that best fitted the need for this module is definitely SQLite, for its velocity, portability, simplicity, and capability to work in memory.

Getting start

There are three main way to get RediSQL.

The first way is to download the public release directly from this link.

These will provide you with the community version that is free, however, you have the possibility to leave a donation (20€ would be the suggested ammount). Indeed, is not necessary to pay anything for the community edition and feel free to just input 0€.

Another option is to download the module from github release

With the .so you can start redis passing the object as argument like so:

./redis-server --loadmodule librediSQL.so 

Please note that you need to run redis > 4.0 to use modules and RediSQL is not an exception.

The last way is to compile the module yourself:

Compiling and contributing

If you want to compile the module yourself or contribute to the project you can simply clone the repo

$ git clone http://github.com/RedBeardLab/rediSQL/
Cloning into 'rediSQL'...
remote: Counting objects: 1404, done.
remote: Total 1404 (delta 0), reused 0 (delta 0), pack-reused 1404
Receiving objects: 100% (1404/1404), 7.28 MiB | 487.00 KiB/s, done.
Resolving deltas: 100% (513/513), done.
Checking connectivity... done.

Then move inside the directory and compile the module:

$ cargo build --release 

At this point, you should have the .so inside the target/release/ directory.

Now launch Redis with the module load will looks similarly to this:

$ ~/redis-4.0-rc1/src/redis-server --loadmodule ./target/release/librediSQL.so 
6833:M 15 Dec 16:25:53.195 * Increased maximum number of open files to 10032 (it was originally set to 1024).
                _._                                                  
           _.-``__ ''-._                                             
      _.-``    `.  `_.  ''-._           Redis 3.9.101 (00000000/0) 64 bit
  .-`` .-```.  ```\/    _.,_ ''-._                                   
 (    '      ,       .-`  | `,    )     Running in standalone mode
 |`-._`-...-` __...-.``-._|'` _.-'|     Port: 6379
 |    `-._   `._    /     _.-'    |     PID: 6833
  `-._    `-._  `-./  _.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |           http://redis.io        
  `-._    `-._`-.__.-'_.-'    _.-'                                   
 |`-._`-._    `-.__.-'    _.-'_.-'|                                  
 |    `-._`-._        _.-'_.-'    |                                  
  `-._    `-._`-.__.-'_.-'    _.-'                                   
      `-._    `-.__.-'    _.-'                                       
          `-._        _.-'                                           
              `-.__.-'                                               

6833:M 15 Dec 16:25:53.197 * Module 'rediSQL__' loaded from ./rediSQL.so
6833:M 15 Dec 16:25:53.197 * The server is now ready to accept connections on port 6379

Walkthrough

After starting redis with the module rediSQL it will be just the redis you learn to love:

$ ~/redis-4.0-rc1/src/redis-cli 
127.0.0.1:6379> 
127.0.0.1:6379> SET A 3
OK
127.0.0.1:6379> GET A
"3"

But you will also able to use all the API described below:

127.0.0.1:6379> REDISQL.CREATE_DB DB
OK
# Start creating a table on the default DB
127.0.0.1:6379> REDISQL.EXEC DB "CREATE TABLE foo(A INT, B TEXT);"
DONE
# Insert some data into the table
127.0.0.1:6379> REDISQL.EXEC DB "INSERT INTO foo VALUES(3, 'bar');"
OK
# Retrieve the data you just inserted
127.0.0.1:6379> REDISQL.EXEC DB "SELECT * FROM foo;"
1) 1) (integer) 3
   2) "bar"
# Of course you can make multiple tables
127.0.0.1:6379> REDISQL.EXEC DB "CREATE TABLE baz(C INT, B TEXT);"
OK
127.0.0.1:6379> REDISQL.EXEC DB "INSERT INTO baz VALUES(3, 'aaa');"
OK
127.0.0.1:6379> REDISQL.EXEC DB "INSERT INTO baz VALUES(3, 'bbb');"
OK
127.0.0.1:6379> REDISQL.EXEC DB "INSERT INTO baz VALUES(3, 'ccc');"
OK
# And of course you can use joins
127.0.0.1:6379> REDISQL.EXEC DB "SELECT * FROM foo, baz WHERE foo.A = baz.C;"

1) 1) (integer) 3
   2) "bar"
   3) (integer) 3
   4) "aaa"
2) 1) (integer) 3
   2) "bar"
   3) (integer) 3
   4) "bbb"
3) 1) (integer) 3
   2) "bar"
   3) (integer) 3
   4) "ccc"
127.0.0.1:6379> 

Also the LIKE operator is included:

127.0.0.1:6379> REDISQL.EXEC DB "CREATE TABLE text_search(t TEXT);"
OK
127.0.0.1:6379> REDISQL.EXEC DB "INSERT INTO text_search VALUES('hello');"
OK
127.0.0.1:6379> REDISQL.EXEC DB "INSERT INTO text_search VALUES('banana');"
OK
127.0.0.1:6379> REDISQL.EXEC DB "INSERT INTO text_search VALUES('apple');"
OK
127.0.0.1:6379> 
127.0.0.1:6379> REDISQL.EXEC DB "SELECT * FROM text_search WHERE t LIKE 'h_llo';"
1) 1) "hello"
127.0.0.1:6379> REDISQL.EXEC DB "SELECT * FROM text_search WHERE t LIKE '%anana';"
1) 1) "banana"
127.0.0.1:6379> REDISQL.EXEC DB "INSERT INTO text_search VALUES('anana');"
OK
127.0.0.1:6379> REDISQL.EXEC DB "SELECT * FROM text_search;"
1) 1) "hello"
2) 1) "banana"
3) 1) "apple"
4) 1) "anana"
127.0.0.1:6379> REDISQL.EXEC DB "SELECT * FROM text_search WHERE t LIKE 'a%';"
1) 1) "apple"
2) 1) "anana"

Now you can create tables, insert data on those tables, make queries, remove elements, everything.

PRO version

The PRO version is available here it cost 990€ / years and of course you have 14 days money back if you are not satisfied with the product.

The PRO version provides two main capabilities and dedicated support from the creators of RediSQL.

Non blocking commands

All (but REDISQL.CREATE_DB) commands in the module blocks the clients and execute the computation in a different thread.

This means that the redis engine is free to serve other clients and it doesn't freeze on long select and it can use more CPU power.

Blocking is the more sensible choice in the general case, however, in some case you may need non blocking command.

The PRO version provide you with that.

In the PRO version is enough to add the suffix .NOW to any command to invoke the blocking version.

AOF & Replication

AOF and Replication in Redis works with the same underneath implementation.

It is quite complex to implement and usefull mostly to companies where redis is a critical piece of infrastructure.

For these reasone the AOF and the Replication are provide in the PRO version.

About the cost

We set up the cost to make it a bargain for any company that actually use the product.

If you consider the ammount of time necessary to replicate this features:

1. Understand the code base of RediSQL
2. Understand how Redis itself works
3. Understand how SQLite works
4. Implement the features
5. Document it
6. Test it
7. Maintaint it

And you multiply for the hour cost of an engineer (~100€/hour).

You will see that RediSQL PRO will pay itself in a little more that 1 day of work.

All this without considering the dedicated support that comes with the plan.

Moreover, up to our knowledge we are the only one to provide a similar product (SQL, in memory inside a cache engine).

API

The complete API are explained in the official documentation that you can access here: API References

Contributing

I am going to accept pull request here on github.

OpenSource and the necessity of real support and charge for my time.

How to Charge for your Open Source by Mike Perham brings good arguments on the necessity to charge for work done by developers, even in the Open Source world.

I myself have started a lot of Open Source project that, eventually, are all dead because I wasn't able to dedicate the right amount of time to them.

I am hoping to find the necessary funds to keep maintain this project.

I am starting with only an Open Source version and then move to an enterprise version adding the necessary features.

License

This software is licensed under the AGPL-v3, it is possible to purchase more permissive licenses.

<RediSQL, SQL capabilities to redis.> Copyright (C) 2017 Simone Mosciatti