Practical use of Apache Cassandra with PHP

A relational database model may not be the best solution for all situations. An alternative approach is to use NoSql. I would like to give a high level overview of Apacha Cassandra NoSql database with a brief introduction into its architecture and data model. This talk will cover main features of Apache Cassandra and provide practical examples of using it.

Talk presented at PHP Usergroup Munich on 26.07.2017

Transcript

1. Practical use of Apache Cassandra with PHP Tatiana Burak Backend Team Lead MegaZebra GmbH
2. What is Apache Cassandra? ▪ Massively scalable ▪ Open source ▪ Non-relational database ▪ Offers: ▪ continuous availability ▪ linear scale performance ▪ operational simplicity ▪ easy data distribution across multiple data centers and cloud availability zones
3. Key Cassandra features ▪ Massively scalable architecture ▪ All nodes may be written to and read from. ▪ Linear scale performance ▪ Continuous availability ▪ Eventual consistency by offering tunable consistency ▪ Flexible and dynamic data model ▪ Multi-data center replication ▪ Data compression ▪ CQL (Cassandra Query Language)
4. Differences from relational databases ▪ Joins and subqueries are not supported ▪ No integrity constraints ▪ No ACID transactions ▪ Restrictions on querying data ▪ Sort criteria needs to be designed ahead
5. Architecture Overview ▪ Masterless “ring” ▪ All nodes play an identical role ▪ No single point of failure ▪ Automatic data distribution ▪ Straightforward replication mechanism ▪ Cloud support
6. Data Model Overview ▪ Highly denormalized model ▪ Highly performant with tables with thousands of columns ▪ Basic objects: ▪ Keyspace ▪ Table ▪ Primary key ▪ Index
7. Cassandra Query Language ▪ Similar to the standart SQL ▪ Operations: ▪ CREATE, ALTER, DROP ▪ INSERT, UPDATE, DELETE, TRUNCATE ▪ SELECT ▪ Datatypes: ▪ Numerical (int, bigint, decimal, etc) ▪ Character (varchar, etc) ▪ Date (timestamp, etc) ▪ Unstructured (blob, etc) ▪ Collections (set, list, map)
15. TTL (Time-to-live) ▪ Supported on the column and table level ▪ TTL value is defined in seconds ▪ Data expires once it exceeds the TTL period ▪ Expiring data uses additional 8 bytes of memory and disk space to record the TTL and grace period
32. Collections ▪ Set ▪ No duplicates ▪ Unordered, but output is sorted ▪ List ▪ Duplicates are possible ▪ Elements are saved in particular order ▪ Map ▪ Key-value pair
37. Querying data ▪ Supported operators in WHERE clause: ▪ =, IN, >, >=, <, <= ▪ Data should be requested “from left to right”
41. Querying data ▪ Restrictions on IN query in collection:
43. Querying data ▪ You can’t request “is null” ▪ Limitations on secondary indexes: ▪ Recommended only for columns with low cardinality of few values ▪ composite secondary indexes are not supported ▪ Materialized views
44. Cassandra + PHP Install cassandra: https://cassandra.apache.org/download/ Install binary driver php: https://github.com/datastax/php-driver/
48. Thank you for your attention! Questions?