Advanced MySQL Topics

Introduction to Indexing

Indexing is a technique used to improve the performance of MySQL queries. An index is a data structure that allows MySQL to quickly locate specific data in a table. There are several types of indexes, including primary key indexes, unique indexes, and composite indexes.

Creating an Index

To create an index, you can use the CREATE INDEX statement. Here's an example:

CREATE INDEX idx_name ON users (name)

This will create a new index called idx_name on the name column of the users table.

Using Indexes

To use an index, you can include the indexed column in the WHERE clause of a query. Here's an example:

SELECT * FROM users WHERE name = 'John Doe'

This will use the idx_name index to quickly locate the row with the name John Doe.

Introduction to Caching

Caching is a technique used to improve the performance of MySQL queries by storing frequently accessed data in memory. There are several types of caching, including query caching and result caching.

Using Caching

To use caching, you can enable the query cache by setting the query_cache_type variable to ON. Here's an example:

SET GLOBAL query_cache_type = ON

This will enable the query cache and store frequently accessed data in memory.

Introduction to Replication

Replication is a technique used to improve the availability and scalability of MySQL databases. There are several types of replication, including master-slave replication and master-master replication.

Using Replication

To use replication, you can set up a master-slave replication configuration by creating a replication user and granting the necessary privileges. Here's an example:

CREATE USER 'replication'@'%' IDENTIFIED BY 'password'
GRANT REPLICATION SLAVE ON *.* TO 'replication'@'%'

This will create a new replication user and grant the necessary privileges to replicate data from the master server.