ITN270.001 Wake Tech1 ITN270 Advanced Internet Databases Lecture 14. Introduction to MySQL Administration and the MySQL Data Directory Topics: –Overview.

ITN270.001 Wake Tech 1

ITN270 Advanced Internet DatabasesLecture 14. Introduction to MySQL Administration

and the MySQL Data Directory

•Topics:–Overview of Administrative Duties–MySQL Data Sirectory

ITN270.001 Wake Tech 2

Overview of Administrative Duties

• The MySQL Server– mysqld

• MySQL Clients & Utilities– mysql

• allows you to send SQL to the server & get results

– mysqladmin• an administrative program

• shutting down

• checking status

ITN270.001 Wake Tech 3

Overview of Administrative Duties

• MySQL Clients & Utilities– mysqlcheck

– isamchk

– myisamchk

• table analysis

• table optimization

• crash recovery

– mysqldump• backing up databases

ITN270.001 Wake Tech 4

Overview of Administrative Duties

• The server’s language– SQL

• The MySQL data directory– structure

• where the files located

– contents• file system

ITN270.001 Wake Tech 5

Administrative Duties

• Server startup & shutdown– mysqld start/stop

• User account maintenance– grant

• Log file maintenance– it may fill up your system

• Database backup & copying– mysqldump

ITN270.001 Wake Tech 6

Administrative Duties

• Database replication– two servers have the same database– changes made in one propagate to the other

• Server configuration & tuning– retrieval– updates

• Multiple servers– each group may have its own server

• MySQL software updates

ITN270.001 Wake Tech 7

Security

• File system security

• Server security– grant access priviliges

ITN270.001 Wake Tech 8

Database Repair & Maintenance

• Crash recovery

• Preventive maintenance

ITN270.001 Wake Tech 9

The MySQL Data Directory

• The MySQL Data Directory Stores– databases– status files– log files

ITN270.001 Wake Tech 10

Location of the Data Directory

• Install from a source distribution– /usr/local/mysql/var

• Install from a binary distribution– /usr/local/mysql/data

• Install from a RPM file– /var/lib/mysql

• MS Windows– c:\mysql\data

ITN270.001 Wake Tech 11

Location of the Data Directory

• Specification of the location of data directory--datadir = dir_name

• Ask the server for location– mysqladmin variables– or

ITN270.001 Wake Tech 12

Structure of the Data Directory

• Contains all the databases & tables

• Tree structure– each database has a sub directory– tables in a database - files in the

subdirectory

• Status & Log files

ITN270.001 Wake Tech 13

How the MySQL Server Provides Access to Data

ITN270.001 Wake Tech 14

How the MySQL Server Provides Access to Data

• When the server does not have exclusive control of the data directory– multiple servers on a single data directory– when run the table repair utilities

ITN270.001 Wake Tech 15

How the MySQL Represents Databases in the File System

• Each database is a subdirectory under c:\mysql\data

• Show DATABASES– dir in Windows

– ls in unix/Linux

• CREATE DATABASES db_name– cd DATADIR

– mkdir db_name

– chmod u=rwx,go-rwx dbname

ITN270.001 Wake Tech 16

How the MySQL Represents Databases in the File System

• DROP DATABASE db_name

– in UNIX• cd DATADIR

• rm -rf db_name

– in Windows• cd DATADIR

• del /s db_name

ITN270.001 Wake Tech 17

How the Tables are represented

• ISAM Tables– *.frm - description file for the format– *.ISD - data file for the contents– *.ISM - index information

• MyISAM Tables– *.frm - format– *.MYD - data– *.MYI - index files

ITN270.001 Wake Tech 18

How the Tables are represented

• MERGE Tables– *.frm

– *.MRG

• BDB Tables– *.frm - description

– *.db - data & index

• InnoDB Tables– *.frm

– tablespace

ITN270.001 Wake Tech 19

OS constrains on Database & Table Naming

• Alphanumeric characters, _, $

• 64 characters long

• other characters can be used by quoting the name in backticks `odd@name`

• case sensitivity

ITN270.001 Wake Tech 20

Factors that Affect Maximum Table Size

• Internal Limits– ISAM: .ISD & .ISM <=4GB– MyISAM: .MYD & .MYI <= 4GB– BDB: 2 TetraBytes– InnoDB: 4Billion x 16KB

• OS limits:– 2GB

• Data Type of AUTO_INCREMENT

ITN270.001 Wake Tech 21

Implications of Data Directory Structure for System Performance

• Multiple files for one table• Table opening time increases with the

number of tables• TIME VS SPACE

– Combine tables need more space– More tables need more time

• Security– More user access same table if combined

ITN270.001 Wake Tech 22

Status & Log Files

• Process ID file: – created when mysql starts– removed when shuts down

• MySQL Log files– General Log file

• Who is connecting

• From Where

• What queries thay are issuing

ITN270.001 Wake Tech 23

Status & Log Files

• MySQL Log files– Update Log file

• queries that update the databases

• useful when there is a crash

– Make sure they will not use up your file system space

ITN270.001 Wake Tech 24

Relocating Data Directory Contents

• Relocation Methods– Specify your data directory at start up– Move the data & create a link

• Assessing the effects of relocation– disk space

• Relocating the entire data directory

ITN270.001 Wake Tech 25

Relocating Data Directory Contents

• Relocating individual databases– shut down the server

– copy or move database directory to ite new location

– Remove the original database directory

– Create a symlink

– Restart the server