Introduction to MySQL Innodb_buffer_pool_size
MySQL innodb_buffer_pool_size is referred to as one of the imperative variables for tuning, especially in the Innodb tables. Comparing to MyISAM tables, the Innodb tables indicate more sensitivity to buffer size. Here, Innodb_buffer_pool denotes the memory space, which consists of several in-memory Innodb data structures, buffers, indexes, caches, and row data.
Normally, we can say that MySQL innodb_buffer_pool_size indicates the configuration parameter in MySQL, which states the quantity of memory assigned by MySQL to the Innodb_buffer_pool. This setting is considered to be one of the essential hosting configurations in MySQL servers, and it should be organized based on the system RAM available.
Syntax
We can show the MySQL innodb_buffer_pool_size variable through a query command with syntax given as follows:
SELECT @@innodb_buffer_pool_size;
In a prevailing server, a user can view the default value of MySQL innodb_buffer_pool_size through the following command query:
SHOW VARIABLES LIKE ‘%innodb_buffer_pool_size%’;
It is suggested that the buffer pool should be able to hold the entire database, but when we study the practical scenario, this may not always be possible. Therefore, it is also superior to assign about 75-80% of the total memory of the server machine present to innodb_buffer_pool_size.
We can also set the value for innodb_buffer_pool_size variable that can be online configured from MySQL 5.7 by the succeeding code:
SET GLOBAL innodb_buffer_pool_size = (value(in bytes));
Note that before making any changes, you should be cautioned to set the value of the above variable online. Since if the server is restarted then, this configuration value may be lost. So, you can keep track of these alterations, and if the server is resumed, then the value can be set on the configuration file named my.cnf.
In the previous versions before MySQL 5.7, the configuration can be done offline. The variable value can also be modified by editing the configuration file my.cnf. For this, open this file and then edit the below line of code under the code section[mysqld] and save the file:
Innodb_buffer_pool_size = X G;
You can now restart the server MySQL to check the value for the new set of configuration running the following command:
SHOW VARIABLES LIKE ‘%innodb_buffer_pool-size%’;
For online process use:
SET GLOBAL innodb_buffer_pool_size = 26843545600;
For offline process use:
innodb_buffer_pool_size = 26G
*For both processes, the server restart is needed.
How does the innodb_buffer_pool_size function work in MySQL?
- Generally, caching is a significant part of calculating as most of the memory is used to progress the access to the best frequently used data by computers. But it depends upon the quantity of data to be accessed; retrieving data on a disk may be 100 to 100,000 times slower.
- MyISAM uses the OS file system cache for caching the database data in which queries are being read over and over again. On the other side, Innodb implements a very altered concept. In this, in place of trusting on OS to perform the correct thing, the Innodb regulates to cache itself – within the Innodb_buffer_pool.
- The MyISAM may perform the kind of OK having default key_buffer_size also with big data set, but then it will be crawled having default innodb_buffer_size. The Innodb buffer pool stores both index pages and data as well; therefore, you do not require vacant space for OS cache, so up to 70-80% values of memory frequently make logic for Innodb database-only installations.
- There are identical rules as key_buffer that are applied – when there is a small set of data, and it will not grow intensely, then there is no need to oversize the variable innodb_buffer_size, so it’s better to implement for memory present.
- We came to know that MySQL innodb_buffer_pool is more than only a Cache, and it actually assists multiple determinations listed below:
- Its big part is used for the process of ‘Data caching.’
- Sharing a similar buffer pool, it is used for ‘Indices caching.’
- The modified or sat dirty data resides in the ‘Buffering’ before it is blushed.
- InnoDB buffer pool also stores internal structures like row locks or Hash Index.
Examples of MySQL innodb_buffer_pool_size
Since MySQL innodb_buffer_pool_size denotes the total cache in the server, for setting this system variable value based on the system RAM size, we will walk through the following two tactics with the pros and cons of each:
Tactic 1: Thumb Rule Method
It defines the common practice to set the variable innodb_buffer_pool_size’s value to 70-80% of the available system RAM space. This method performs better in many cases but is not optimum in all configurations as it cannot wholly control the big size of RAM or utilize it for the cache.
Tactic 2: Further Nuanced Method
Here, we will understand the internal aspects of the InnoDB buffer pool and its collaborations that are even defined in the book named High-Performance MySQL.
Below are the approaches to calculate the MySQL innodb_buffer_pool_size variable:
- Initially, starting with the total RAM present.
- Minus an appropriate quantity for all OS requirements.
- Minus an appropriate quantity for all MySQL requirements such as many MySQL buffers, connection pools, replication linked buffers, and temporary tables.
- The division of the output by 150% is an estimate of the above needed to regulate the buffer pool itself.
Let us discuss some of the demonstrations using the MySQL innodb_buffer_pool_size variable query and its uses in MySQL server:
You can run the code below in the information_schema database in the server to view the innodb_buffer_pool_size value:
SELECT @@innodb_buffer_pool_size;
Output:
To display the default innodb_buffer_pool_size value in the existing server:
SHOW VARIABLES LIKE '%innodb_buffer_pool_size%';
Output:
Conclusion
MySQL innodb_buffer_pool_size is an essential variable for the whole MySQL server, which has brought radical developments over the last few years in the Innodb storage engine structures. The position of the Innodb storage engine cultivates several times over MyISAM after Oracle has acquired MySQL. Due to its ACID obedience properties, it is important though MySQL maintenances other various pluggable storage engines. The latest enhancements in MySQL 5.7 named the configuration of online innodb_buffer_pool_size has made it extremely flexible and helped to receive the best performance and not give the long downtime.
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