What does key buffer mean?
The key buffer is MyISAM specific, a structure for index blocks that contains a number of block buffers where the most-used index blocks are placed. It’s mean for minimizing disk I/O, because memory is still faster than hard drives [currently].
Which parameter is used to tune the buffer size for MyISAM engine tables*?
The read_buffer_size system variable determines the buffer size. It is also useful for MyISAM, but this variable affects all storage engines as well.
What is Key_buffer_size?
key_buffer_size is a MyISAM variable which determines the size of the index buffers held in memory, which affects the speed of index reads. A good rule of thumb for servers consisting particularly of MyISAM tables is for about 25% or more of the available server memory to be dedicated to the key buffer.
What is key efficiency in MySQL?
“Key Efficiency” is an indication of how much value you are getting from the index caches held within MySQL’s memory. If your key efficiency is high, then most often MySQL is performing key lookups from within memory space, which is much faster than having to retrieve the relevant index blocks from disk.
What is InnoDB buffer pool size?
InnoDB buffer pool is the memory space that holds many in-memory data structures of InnoDB, buffers, caches, indexes and even row-data. innodb_buffer_pool_size is the MySQL configuration parameter that specifies the amount of memory allocated to the InnoDB buffer pool by MySQL.
What is difference between MyISAM and InnoDB?
Here are a few of the major differences between InnoDB and MyISAM: InnoDB has row-level locking. MyISAM only has full table-level locking. InnoDB has what is called referential integrity which involves supporting foreign keys (RDBMS) and relationship constraints, MyISAM does not (DMBS).
Why MyISAM gives the best performance?
MyISAM is designed with the idea that your database is queried far more than its updated and as a result it performs very fast read operations. If your read to write(insert|update) ratio is less than 15% its better to use MyISAM.
What is Max_allowed_packet?
In a nutshell, max_allowed_packet is the maximum size of a MySQL network protocol packet that the server can create or read. It has a default value of 1MB (<= 5.6. 5) or 4MB (>= 5.6. 6) and a maximum size of 1GB.
What is Innodb_log_buffer_size?
buffer pool is the amount of memory (RAM) that InnoDB is allowed to use to cache active data set (indexes etc.) to make various queries quick. The log buffer is amount of memory reserved to log queries grouped in a transaction. Every second InnoDB will try to flush data from log buffer to the hard drive.
What is InnoDB buffer usage?
How do I know my InnoDB size?
The usage of the InnoDB Buffer Pool can be measured with the SHOW GLOBAL STATUS LIKE ‘Innodb_buffer_pool_pages_%’ command. The sum of data, misc and free pages is equivalent to total pages. And the number of total pages multiplied by Innodb_page_size corresponds to your innodb_buffer_pool_size.
Where is the keyboard buffer on a computer?
A keyboard buffer is a small area in the computer’s memory (RAM) that is used to temporarily store the keystrokes from the keyboard before they are processed by the CPU.
How to tune the MySQL key buffer performance?
It’s important to get that rate as close to 100% as possible. For large databases, however, 95%-99% is the best that can be achieved and indicates a well tuned system. The MyISAM storage engine uses a key buffer for caching index data from disk.
How is the key buffer in MyISAM used?
MyISAM Key Buffer The MyISAM storage engine uses a key buffer for caching index data from disk. Actual row data is buffered by the operating system file cache, and this difference requires another tuning method than for the InnoDB buffer pool.
Where does the keyboard buffer go in time sharing?
In time-sharing systems, the location of the buffer depends on whether communications is full- duplex or half-duplex. In full-duplex systems, keystrokes are transmitted one by one. As the main computer receives each keystroke, it ordinarily appends the character which it represents to the end of the keyboard buffer.
