Redis Functions

What is Wrong with Eval Script

Redis functions are available after Redis 7. Prior versions to that scripting in Redis are available through the EVAL command that allows execution of the Lua script by the server. Executing our application logic inside Redis efficiently and automatically is the core use case for the Eval Scripts. These scripts help us perform conditional updates across multiple keys, perhaps combining several different data types.

What are Redis Functions

Redis Functions provide us with the same core functionality as scripts but are also first-class software artefacts of the databases. Redis manages these functions as an integral part of the database and ensures they are available via data persistence and replication. Functions are part of the database and thus need to be declared before use. Applications aren't required to load them during runtime nor risk aborted transactions. An application that uses functions depends only on its APIs rather than on the embedded script logic in the database.

Redis Functions are used to determine between the programming language used for writing functions and their management by the server. Lua is the only language interpreter that Redis supports presently as an embedded execution engine. Below is the command for the individual function mentioned.

Loading an Empty Library 

redis> FUNCTION LOAD "#!lua name=mylib\n"
(error) ERR No functions registered

Register a Single Function

#!lua name=mylib
redis.register_function(
  'knockknock',
  function() return 'What is your Name?' end
)

Call the Registered Function

redis> FUNCTION LOAD "#!lua name=mylib\nredis.register_function('knockknock', function() return 'Who\\'s there?' end)"
mylib
redis> FCALL knockknock 0
"Who's there?"

Frequently Asked Questions

What is Redis?

Redis is defined as an open-source (BSD licensed), stored data structure in memory and used as a database, cache, message broker, and streaming the engine.

What is Redis Scripting?

Redis is very popular and is used by most tech giants like Twitter, Github, Snapchat, Stack Overflow etc.

Redis is written in what language is it supported on all platforms?

Redis is written in ANSI C language, and it works on most the POSIX systems like Linux, *BSD, and Mac OS X.

What is the Maximum Execution Time?

Maximum Execution Time is a default timeout for scripts to run. Scripts are subjected to a maximum execution time (usually the default value set by five seconds). The timeout limit is placed to handle accidental infinite loops.

What are Redis Functions?

Redis Functions are used to determine between the programming language used for writing functions and their management by the server. It provides us with the same core functionality as scripts but is also a first-class software artefact of the databases. Redis manages these functions as an integral part of the database and ensures they are available via data persistence and replication.

Conclusion

In this article, we have extensively discussed Big Structured Data in detail. We have also briefly explained different sources of Big Structured Data. 

We hope that this blog has helped you enhance your knowledge regarding Big Data. To learn about Big Data and Hadoop, practice some quality SQL questions and visit our blogs on Databases in Coding Ninjas Studio. If you are preparing for an interview, visit our Interview Experience Section. To become more confident in DSA, try out Interview Problems in our Code studio. Do upvote our blog to help other ninjas grow. Happy Coding!