MySQL - Improve Performance for Multi Country - mysql

Question

I have a table company, which has a column called country_id is a reference of country table Primary Key ID.
CREATE TABLE `company` (
`Id` INT(11) NOT NULL,
`Name` VARCHAR(100) NOT NULL,
`Symbol` VARCHAR(50) NOT NULL,
`Industry` VARCHAR(100) NOT NULL,
`Type` VARCHAR(20) NOT NULL,
'country_id' INT(11) NOT NULL,
PRIMARY KEY (`Id`),
CONSTRAINT `company_ibfk_1` FOREIGN KEY (`country_id`) REFERENCES `country` (`Id`)
)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB;
In this table has multiple company for multiple country. Like the below table.
My company table has huge data. I want to improve the select query on company table performance based on country. Select query will be like
select * from company where country_id = 2
What will be the best design approach? Do I need to add indexing on country_id column or do I need to do the partitioning based on the country_id column? Please suggest.

Answer 1

if you have big count of countries (more then 100), you should use index.
If few number countries in your DB would be better to use partitioning.
But this option has one big disadvantage. If you will add new country, you should add new partition linked to new one.

Answer 2

InnoDB will automatically generate index on your foreign key country_id, so you do not need to indexing on it.
About partition, InnoDB does not support foreign key and partition together and if you use partition you can just create an index on country_id (not foreign key) and join both tables if you needed.
If you have more than one million records on company and your query is not fast enough, you can use partition, like below:
CREATE TABLE `company` (
`Id` INT(11) NOT NULL,
`Name` VARCHAR(100) NOT NULL,
`Symbol` VARCHAR(50) NOT NULL,
`Industry` VARCHAR(100) NOT NULL,
`Type` VARCHAR(20) NOT NULL,
`country_id` INT(11) NOT NULL,
PRIMARY KEY (`Id`),
INDEX (`country_id`)
)
PARTITION BY RANGE (`country_id`) (
PARTITION P1 VALUES LESS THAN (20),
PARTITION P2 VALUES LESS THAN (50),
PARTITION P3 VALUES LESS THAN (100),
PARTITION P4 VALUES LESS THAN MAXVALUE)
COLLATE='latin1_swedish_ci'
ENGINE=InnoDB;