5.2.1  Database manipulation

MySQL database objects are always stored in one directory. This gives 

advantage of simplicity but with a big performance bottleneck because of slow 

disk seek, slow search, and non indexing of data. MySQL depends on the 

operating system's capabilities for distributing its data across disks. It uses 

symbolic links to different disks for different databases, and for database and 

table distributing.

On Linux machines MySQL also uses file system mounting options but most of 

the time MySQL uses symbolic link. This can be done by creating a directory 

where you have an extra space:

bash>cd 

bash>mkdir mysqldata

then creates a symbolic link to the newly created directory using:

bash>cd /usr/local/mysql

bash>ln  sf /mysqldata data

Now you can create a database from MySQL mysql prompt using:

mysql>create database itsodb

MySQL users can distribute tables using symbolic linking or the data and index 

directory options of 

create table

.

MySQL does not provide anything for logically dividing the database into different 

nodes or distributing tables onto different table spaces except for the optional 

InnoDB table, which supports multiple table space distributed in different files. 

Also, MySQL does not give any options for distributing tables into different 

segments

according to usage or the user. We discuss this in 5.3,  Other 

considerations  on page 107.

DB2 UDB uses a better approach for the logical and physical distribution of the 

database and the database elements in different sectors. While migrating the 

database from MySQL to DB2 UDB, you can use these features for the 

performance enhancement of your application.

Instance

A DB2 UDB server can have more then one instance. One instance can have 

multiple databases. One instance per application database has the advantage 

that the application and database support do not have to coordinate with others 

for activities that need to take database or instance off line. For migration 

purposes, you can create one instance for your database application 

environment. It can be created easily using the 

db2icrt 

command:

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MySQL to DB2 UDB Conversion Guide