In Apache Cassandra Lunch #59: Functions in Cassandra, we discussed the functions that are usable inside of the Cassandra database. The live recording of Cassandra Lunch, which includes a more in-depth discussion and a demo, is embedded below in case you were not able to attend live.

1. Version 1.0
Functions In Cassandra
An Anant Corporation Story.
Default Functions, Aggregations, UDFs, and UDAs in Cassandra

2. Cassandra Native Functions
● Functions transform one or more column values into a new value
● Cassandra Native functions
○ Blob conversion functions
○ UUID and Timeuuid functions
○ Token function
○ WRITETIME function
○ TTL function
○ Standard aggregate functions such as MIN(), MAX(), SUM(), and AVG().
○ TOKEN function

3. Cassandra Native Functions (2)
● Blob conversion functions
○ Blob type stores raw binary data as a string of hex characters
○ Inbuilt functions convert between blob and other native Cassandra types
■ typeAsBlob(value)
■ blobAsType(value)
● UUID and Timeuuid functions
○ uuid() generates a random uuid
○ dateOf() and unixTimestampOf() extract the date and timestamp from a timeuuid
○ minTimeuuid() and maxTimeuuid() generate timeuuid consistent with a given date, now() does the same
with the current time
○ Timestamp, date conversion functions
● Token function
○ Used to give the token that Cassandra uses to sort rows among nodes

4. Cassandra Native Functions (3)
● WRITETIME function
○ Returns the date and time that a particular column was written to the database
● TTL function
○ Returns the number of seconds before a particular cell is replaced with a tombstone, to later be deleted
● Standard aggregate functions such as MIN(), MAX(), SUM(), and AVG()

5. User Defined Functions
● User-defined functions allow execution of user-provided code in Cassandra. By default,
Cassandra supports defining functions in Java and JavaScript.
● UDFs exists on the keyspace level as part of the Cassandra schema
○ They get replicated to each node
● It is possible to use user-defined type in functions, as well as collections and tuples
● Can be used as part of select, insert, and update statements
● The CREATE FUNCTION statement can be use with OR REPLACE or with IF NOT EXISTS

6. Demo

7. Strategy: Scalable Fast Data
Architecture: Cassandra, Spark, Kafka
Engineering: Node, Python, JVM,CLR
Operations: Cloud, Container
Rescue: Downtime!! I need help.
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