ANiq - A scalable distinct value estimation system.

Get a cardinality of a set, multiple set unions and intersections!

WARNING! Highly experimental. Use at your own risk!

INTRO

To see what problem ANiq is tackling, please read ANiq — counting distinct values at scale

REQUIREMENTS

• Node.js v6+
• Redis v4+

INSTALLATION

npm install aniq

CONFIGURATION

Copy sample.json to production.json. Modify per your settings.

RUNNING

• cd node_modules/aniq/
• NODE_ENV=production node app.js

PRODUCTION USAGE

1. For making ANiq scalable and stable it is recommended to use a process manager such as PM2.
2. For best performance put ANiq behind a reverse proxy with proper load balancing (i.e. Nginx).

API

Add

Add a member to KMV

URL : /add/:key/

URL Parameters : key=[string] where key is a name of the KMV.

Method : PUT

Data constraints

[
    "[string]",
    "[string]",
    "...etc"
]

OR

[string]

Data example As an array or string

[
    "Canada",
    "US",
    "Mexico"
]

OR

Canada

Success Response

Condition : If key and at least one member is provided.

Code : 200 OK

Content example

{
    "result": "OK"
}

Error Responses

Condition : If no member value is provided

Code : 400 BAD REQUEST

Content :

{
    "code": "api-2",
    "message": "Members parameter should either be a string or an array of strings"
}

OR

Condition : If no key is provided.

Code : 404 NOT FOUND

Content :

{"code": "ResourceNotFound"}

Cardinality

Return the cardinality of a KMV

URL : /cardinality/:key/

URL Parameters : key=[string] where key is a name of the KMV.

Method : GET

Success Response

Condition : If key is provided.

Code : 200 OK

Content example

{
    "result": "[int]"
}

Error Responses

Condition : If no key is provided.

Code : 404 NOT FOUND

Content :

{"code": "ResourceNotFound"}

Union

Return the cardinality of a multiple KMV union.

URL : /union/:keys/

URL Parameters : keys=[string,] where keys is comma separated names of the KMVs.

Method : GET

Success Response

Condition : If two or more keys are provided.

Code : 200 OK

Content example

{
    "result": "[int]"
}

Error Responses

Condition : If no key is provided.

Code : 404 NOT FOUND

Content :

{"code": "ResourceNotFound"}

OR

Condition : If only one key is provided

Code : 400 BAD REQUEST

Content :

{
    "code": "api-3",
    "message": "Keys parameter should be an array of two or more key strings"
}

Intersection

Return the cardinality of a multiple KMV intersection.

URL : /union/:keys/

URL Parameters : keys=[string,] where keys is comma separated names of the KMVs.

Method : GET

Success Response

Condition : If one or more keys are provided.

Code : 200 OK

Content example

{
    "result": "[int]"
}

Error Responses

Condition : If no key is provided.

Code : 404 NOT FOUND

Content :

{"code": "ResourceNotFound"}

OR

Condition : If only one key is provided

Code : 400 BAD REQUEST

Content :

{
    "code": "api-3",
    "message": "Keys parameter should be an array of two or more key strings"
}

Scaling

• To scale the app itself - add more Node.js clients
• To scale Redis servers - add more of those
• To scale Redis processes - add more per server

Sample architecture is as follows:

r1  r2  r3  r4    r5  r6  r7  r8 (redis instances)
      s1                s2       (redis servers)
               f1                (client)

s1, s2 and f1 can be on the same server. r1-r4 and r5-r8 should be on separate servers.
s1, s1 and f1 should be two or more identical servers to remove single point of failure.
f1 has a replication factor and writePolicy of 2. If you don't want replication or are using Redis standard one, you can disable this via config.

Testing

NOTE: Requires Redis (localhost and ports 6379-6832) to be installed (4 instances for full testing)

Copy sample.json to testing.json. Modify per your settings.

npm test

Linting

npm run lint

Contributing

Go nuts! Just don't forget to test and lint. Credit will be given where it's due.

Future

• Benchmarks
• Lots of fixes and optimizations