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How MySQL stores data on disk?
Basically mySQL stores data in files in your hard disk. It stores the files in a specific directory that has the system variable “datadir”. Opening a mysql console and running the following command will tell you exactly where the folder is located.
How does MySQL process data?
MySQL parses queries to create an internal structure (the parse tree), and then applies a variety of optimizations. These can include rewriting the query, determining the order in which it will read tables, choosing which indexes to use, and so on.
Does MySQL write to disk?
There’s a difference between “write” and “flush” – writing a file to disk means that MySQL has told the Operating System to make a change, but the Operating System might choose to wait before it actually writes the file to disk. “Flushing” the file means MySQL will force the OS to physically write it to disk.
Where is the data stored in MySQL?
The default data directory location is C:\Program Files\MySQL\MySQL Server 8.0\data , or C:\ProgramData\Mysql on Windows 7 and Windows Server 2008. The C:\ProgramData directory is hidden by default.
How data is stored on a disk?
Data is stored on a hard drive in binary code, using 1s and 0s. The information is spread out on the magnetic layer of the disk(s) and are read or written by the read heads that ‘float’ above the surface thanks to the layer of air produced by the ultra fast rotation of the disk.
How often does MySQL write to disk?
Writing modified pages back to disk Writing down dirty pages happens as part of InnoDB’s background process which continually performs work every 1 second, and it adjusts well to peaks and troughs in load with a feature introduced in MySQL 5.5 and further improved in MySQL 5.6 called adaptive flushing.
How does MySQL store data in a single file?
Some DBMSes store the whole database in a single file, some split tables, indexes and other object kinds to separate files, some split files not by object kind but by some storage/size criteria, some can even entirely bypass the file system, etc etc…
Why does MySQL use so much disk space?
If you have a very large number of tables, it can be slow, as you have already discovered.
How does MySQL store data to achieve performance?
As for your specific question of performance, relational data is very “susceptible” to indexing and clustering, which is richly exploited by DBMSes to achieve performance. On top of that, the set-based nature of SQL lets the DBMS choose the optimal way to retrieve the data (in theory at least, some DBMSes are better at that than the others).
How to check MySQL disk usage on Linux?
Assuming that your MySQL host is running on Linux. Once you know where the data is stored, you can check disk usage with du command. For example on Ubuntu sudo du -h /var/lib/mysql. Thanks for contributing an answer to Database Administrators Stack Exchange!